commit f85086f95f upstream.
In register_mem_sect_under_node() the system_state's value is checked to
detect whether the call is made during boot time or during an hot-plug
operation. Unfortunately, that check against SYSTEM_BOOTING is wrong
because regular memory is registered at SYSTEM_SCHEDULING state. In
addition, memory hot-plug operation can be triggered at this system
state by the ACPI [1]. So checking against the system state is not
enough.
The consequence is that on system with interleaved node's ranges like this:
Early memory node ranges
node 1: [mem 0x0000000000000000-0x000000011fffffff]
node 2: [mem 0x0000000120000000-0x000000014fffffff]
node 1: [mem 0x0000000150000000-0x00000001ffffffff]
node 0: [mem 0x0000000200000000-0x000000048fffffff]
node 2: [mem 0x0000000490000000-0x00000007ffffffff]
This can be seen on PowerPC LPAR after multiple memory hot-plug and
hot-unplug operations are done. At the next reboot the node's memory
ranges can be interleaved and since the call to link_mem_sections() is
made in topology_init() while the system is in the SYSTEM_SCHEDULING
state, the node's id is not checked, and the sections registered to
multiple nodes:
$ ls -l /sys/devices/system/memory/memory21/node*
total 0
lrwxrwxrwx 1 root root 0 Aug 24 05:27 node1 -> ../../node/node1
lrwxrwxrwx 1 root root 0 Aug 24 05:27 node2 -> ../../node/node2
In that case, the system is able to boot but if later one of theses
memory blocks is hot-unplugged and then hot-plugged, the sysfs
inconsistency is detected and this is triggering a BUG_ON():
kernel BUG at /Users/laurent/src/linux-ppc/mm/memory_hotplug.c:1084!
Oops: Exception in kernel mode, sig: 5 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
Modules linked in: rpadlpar_io rpaphp pseries_rng rng_core vmx_crypto gf128mul binfmt_misc ip_tables x_tables xfs libcrc32c crc32c_vpmsum autofs4
CPU: 8 PID: 10256 Comm: drmgr Not tainted 5.9.0-rc1+ #25
Call Trace:
add_memory_resource+0x23c/0x340 (unreliable)
__add_memory+0x5c/0xf0
dlpar_add_lmb+0x1b4/0x500
dlpar_memory+0x1f8/0xb80
handle_dlpar_errorlog+0xc0/0x190
dlpar_store+0x198/0x4a0
kobj_attr_store+0x30/0x50
sysfs_kf_write+0x64/0x90
kernfs_fop_write+0x1b0/0x290
vfs_write+0xe8/0x290
ksys_write+0xdc/0x130
system_call_exception+0x160/0x270
system_call_common+0xf0/0x27c
This patch addresses the root cause by not relying on the system_state
value to detect whether the call is due to a hot-plug operation. An
extra parameter is added to link_mem_sections() detailing whether the
operation is due to a hot-plug operation.
[1] According to Oscar Salvador, using this qemu command line, ACPI
memory hotplug operations are raised at SYSTEM_SCHEDULING state:
$QEMU -enable-kvm -machine pc -smp 4,sockets=4,cores=1,threads=1 -cpu host -monitor pty \
-m size=$MEM,slots=255,maxmem=4294967296k \
-numa node,nodeid=0,cpus=0-3,mem=512 -numa node,nodeid=1,mem=512 \
-object memory-backend-ram,id=memdimm0,size=134217728 -device pc-dimm,node=0,memdev=memdimm0,id=dimm0,slot=0 \
-object memory-backend-ram,id=memdimm1,size=134217728 -device pc-dimm,node=0,memdev=memdimm1,id=dimm1,slot=1 \
-object memory-backend-ram,id=memdimm2,size=134217728 -device pc-dimm,node=0,memdev=memdimm2,id=dimm2,slot=2 \
-object memory-backend-ram,id=memdimm3,size=134217728 -device pc-dimm,node=0,memdev=memdimm3,id=dimm3,slot=3 \
-object memory-backend-ram,id=memdimm4,size=134217728 -device pc-dimm,node=1,memdev=memdimm4,id=dimm4,slot=4 \
-object memory-backend-ram,id=memdimm5,size=134217728 -device pc-dimm,node=1,memdev=memdimm5,id=dimm5,slot=5 \
-object memory-backend-ram,id=memdimm6,size=134217728 -device pc-dimm,node=1,memdev=memdimm6,id=dimm6,slot=6 \
Fixes: 4fbce63391 ("mm/memory_hotplug.c: make register_mem_sect_under_node() a callback of walk_memory_range()")
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Scott Cheloha <cheloha@linux.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200915094143.79181-3-ldufour@linux.ibm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c1d0da8335 upstream.
Patch series "mm: fix memory to node bad links in sysfs", v3.
Sometimes, firmware may expose interleaved memory layout like this:
Early memory node ranges
node 1: [mem 0x0000000000000000-0x000000011fffffff]
node 2: [mem 0x0000000120000000-0x000000014fffffff]
node 1: [mem 0x0000000150000000-0x00000001ffffffff]
node 0: [mem 0x0000000200000000-0x000000048fffffff]
node 2: [mem 0x0000000490000000-0x00000007ffffffff]
In that case, we can see memory blocks assigned to multiple nodes in
sysfs:
$ ls -l /sys/devices/system/memory/memory21
total 0
lrwxrwxrwx 1 root root 0 Aug 24 05:27 node1 -> ../../node/node1
lrwxrwxrwx 1 root root 0 Aug 24 05:27 node2 -> ../../node/node2
-rw-r--r-- 1 root root 65536 Aug 24 05:27 online
-r--r--r-- 1 root root 65536 Aug 24 05:27 phys_device
-r--r--r-- 1 root root 65536 Aug 24 05:27 phys_index
drwxr-xr-x 2 root root 0 Aug 24 05:27 power
-r--r--r-- 1 root root 65536 Aug 24 05:27 removable
-rw-r--r-- 1 root root 65536 Aug 24 05:27 state
lrwxrwxrwx 1 root root 0 Aug 24 05:25 subsystem -> ../../../../bus/memory
-rw-r--r-- 1 root root 65536 Aug 24 05:25 uevent
-r--r--r-- 1 root root 65536 Aug 24 05:27 valid_zones
The same applies in the node's directory with a memory21 link in both
the node1 and node2's directory.
This is wrong but doesn't prevent the system to run. However when
later, one of these memory blocks is hot-unplugged and then hot-plugged,
the system is detecting an inconsistency in the sysfs layout and a
BUG_ON() is raised:
kernel BUG at /Users/laurent/src/linux-ppc/mm/memory_hotplug.c:1084!
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
Modules linked in: rpadlpar_io rpaphp pseries_rng rng_core vmx_crypto gf128mul binfmt_misc ip_tables x_tables xfs libcrc32c crc32c_vpmsum autofs4
CPU: 8 PID: 10256 Comm: drmgr Not tainted 5.9.0-rc1+ #25
Call Trace:
add_memory_resource+0x23c/0x340 (unreliable)
__add_memory+0x5c/0xf0
dlpar_add_lmb+0x1b4/0x500
dlpar_memory+0x1f8/0xb80
handle_dlpar_errorlog+0xc0/0x190
dlpar_store+0x198/0x4a0
kobj_attr_store+0x30/0x50
sysfs_kf_write+0x64/0x90
kernfs_fop_write+0x1b0/0x290
vfs_write+0xe8/0x290
ksys_write+0xdc/0x130
system_call_exception+0x160/0x270
system_call_common+0xf0/0x27c
This has been seen on PowerPC LPAR.
The root cause of this issue is that when node's memory is registered,
the range used can overlap another node's range, thus the memory block
is registered to multiple nodes in sysfs.
There are two issues here:
(a) The sysfs memory and node's layouts are broken due to these
multiple links
(b) The link errors in link_mem_sections() should not lead to a system
panic.
To address (a) register_mem_sect_under_node should not rely on the
system state to detect whether the link operation is triggered by a hot
plug operation or not. This is addressed by the patches 1 and 2 of this
series.
Issue (b) will be addressed separately.
This patch (of 2):
The memmap_context enum is used to detect whether a memory operation is
due to a hot-add operation or happening at boot time.
Make it general to the hotplug operation and rename it as
meminit_context.
There is no functional change introduced by this patch
Suggested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Scott Cheloha <cheloha@linux.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200915094143.79181-1-ldufour@linux.ibm.com
Link: https://lkml.kernel.org/r/20200915132624.9723-1-ldufour@linux.ibm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d3f7b1bb20 upstream.
Currently to make sure that every page table entry is read just once
gup_fast walks perform READ_ONCE and pass pXd value down to the next
gup_pXd_range function by value e.g.:
static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end,
unsigned int flags, struct page **pages, int *nr)
...
pudp = pud_offset(&p4d, addr);
This function passes a reference on that local value copy to pXd_offset,
and might get the very same pointer in return. This happens when the
level is folded (on most arches), and that pointer should not be
iterated.
On s390 due to the fact that each task might have different 5,4 or
3-level address translation and hence different levels folded the logic
is more complex and non-iteratable pointer to a local copy leads to
severe problems.
Here is an example of what happens with gup_fast on s390, for a task
with 3-level paging, crossing a 2 GB pud boundary:
// addr = 0x1007ffff000, end = 0x10080001000
static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end,
unsigned int flags, struct page **pages, int *nr)
{
unsigned long next;
pud_t *pudp;
// pud_offset returns &p4d itself (a pointer to a value on stack)
pudp = pud_offset(&p4d, addr);
do {
// on second iteratation reading "random" stack value
pud_t pud = READ_ONCE(*pudp);
// next = 0x10080000000, due to PUD_SIZE/MASK != PGDIR_SIZE/MASK on s390
next = pud_addr_end(addr, end);
...
} while (pudp++, addr = next, addr != end); // pudp++ iterating over stack
return 1;
}
This happens since s390 moved to common gup code with commit
d1874a0c28 ("s390/mm: make the pxd_offset functions more robust") and
commit 1a42010cdc ("s390/mm: convert to the generic
get_user_pages_fast code").
s390 tried to mimic static level folding by changing pXd_offset
primitives to always calculate top level page table offset in pgd_offset
and just return the value passed when pXd_offset has to act as folded.
What is crucial for gup_fast and what has been overlooked is that
PxD_SIZE/MASK and thus pXd_addr_end should also change correspondingly.
And the latter is not possible with dynamic folding.
To fix the issue in addition to pXd values pass original pXdp pointers
down to gup_pXd_range functions. And introduce pXd_offset_lockless
helpers, which take an additional pXd entry value parameter. This has
already been discussed in
https://lkml.kernel.org/r/20190418100218.0a4afd51@mschwideX1
Fixes: 1a42010cdc ("s390/mm: convert to the generic get_user_pages_fast code")
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: <stable@vger.kernel.org> [5.2+]
Link: https://lkml.kernel.org/r/patch.git-943f1e5dcff2.your-ad-here.call-01599856292-ext-8676@work.hours
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4166343058 upstream.
SWP_FS is used to make swap_{read,write}page() go through the
filesystem, and it's only used for swap files over NFS. So, !SWP_FS
means non NFS for now, it could be either file backed or device backed.
Something similar goes with legacy SWP_FILE.
So in order to achieve the goal of the original patch, SWP_BLKDEV should
be used instead.
FS corruption can be observed with SSD device + XFS + fragmented
swapfile due to CONFIG_THP_SWAP=y.
I reproduced the issue with the following details:
Environment:
QEMU + upstream kernel + buildroot + NVMe (2 GB)
Kernel config:
CONFIG_BLK_DEV_NVME=y
CONFIG_THP_SWAP=y
Some reproducible steps:
mkfs.xfs -f /dev/nvme0n1
mkdir /tmp/mnt
mount /dev/nvme0n1 /tmp/mnt
bs="32k"
sz="1024m" # doesn't matter too much, I also tried 16m
xfs_io -f -c "pwrite -R -b $bs 0 $sz" -c "fdatasync" /tmp/mnt/sw
xfs_io -f -c "pwrite -R -b $bs 0 $sz" -c "fdatasync" /tmp/mnt/sw
xfs_io -f -c "pwrite -R -b $bs 0 $sz" -c "fdatasync" /tmp/mnt/sw
xfs_io -f -c "pwrite -F -S 0 -b $bs 0 $sz" -c "fdatasync" /tmp/mnt/sw
xfs_io -f -c "pwrite -R -b $bs 0 $sz" -c "fsync" /tmp/mnt/sw
mkswap /tmp/mnt/sw
swapon /tmp/mnt/sw
stress --vm 2 --vm-bytes 600M # doesn't matter too much as well
Symptoms:
- FS corruption (e.g. checksum failure)
- memory corruption at: 0xd2808010
- segfault
Fixes: f0eea189e8 ("mm, THP, swap: Don't allocate huge cluster for file backed swap device")
Fixes: 38d8b4e6bd ("mm, THP, swap: delay splitting THP during swap out")
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Acked-by: Rafael Aquini <aquini@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Carlos Maiolino <cmaiolino@redhat.com>
Cc: Eric Sandeen <esandeen@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200820045323.7809-1-hsiangkao@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit abb242f571 ]
The move_lock is a per-memcg lock, but the VM accounting code that needs
to acquire it comes from the page and follows page->mem_cgroup under RCU
protection. That means that the page becomes unlocked not when we drop
the move_lock, but when we update page->mem_cgroup. And that assignment
doesn't imply any memory ordering. If that pointer write gets reordered
against the reads of the page state - page_mapped, PageDirty etc. the
state may change while we rely on it being stable and we can end up
corrupting the counters.
Place an SMP memory barrier to make sure we're done with all page state by
the time the new page->mem_cgroup becomes visible.
Also replace the open-coded move_lock with a lock_page_memcg() to make it
more obvious what we're serializing against.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-3-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d6c1f098f2 ]
"prev_offset" is a static variable in swapin_nr_pages() that can be
accessed concurrently with only mmap_sem held in read mode as noticed by
KCSAN,
BUG: KCSAN: data-race in swap_cluster_readahead / swap_cluster_readahead
write to 0xffffffff92763830 of 8 bytes by task 14795 on cpu 17:
swap_cluster_readahead+0x2a6/0x5e0
swapin_readahead+0x92/0x8dc
do_swap_page+0x49b/0xf20
__handle_mm_fault+0xcfb/0xd70
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x715
page_fault+0x34/0x40
1 lock held by (dnf)/14795:
#0: ffff897bd2e98858 (&mm->mmap_sem#2){++++}-{3:3}, at: do_page_fault+0x143/0x715
do_user_addr_fault at arch/x86/mm/fault.c:1405
(inlined by) do_page_fault at arch/x86/mm/fault.c:1535
irq event stamp: 83493
count_memcg_event_mm+0x1a6/0x270
count_memcg_event_mm+0x119/0x270
__do_softirq+0x365/0x589
irq_exit+0xa2/0xc0
read to 0xffffffff92763830 of 8 bytes by task 1 on cpu 22:
swap_cluster_readahead+0xfd/0x5e0
swapin_readahead+0x92/0x8dc
do_swap_page+0x49b/0xf20
__handle_mm_fault+0xcfb/0xd70
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x715
page_fault+0x34/0x40
1 lock held by systemd/1:
#0: ffff897c38f14858 (&mm->mmap_sem#2){++++}-{3:3}, at: do_page_fault+0x143/0x715
irq event stamp: 43530289
count_memcg_event_mm+0x1a6/0x270
count_memcg_event_mm+0x119/0x270
__do_softirq+0x365/0x589
irq_exit+0xa2/0xc0
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200402213748.2237-1-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit cbfc35a486 ]
In a couple of places in the slub memory allocator, the code uses
"s->offset" as a check to see if the free pointer is put right after the
object. That check is no longer true with commit 3202fa62fb ("slub:
relocate freelist pointer to middle of object").
As a result, echoing "1" into the validate sysfs file, e.g. of dentry,
may cause a bunch of "Freepointer corrupt" error reports like the
following to appear with the system in panic afterwards.
=============================================================================
BUG dentry(666:pmcd.service) (Tainted: G B): Freepointer corrupt
-----------------------------------------------------------------------------
To fix it, use the check "s->offset == s->inuse" in the new helper
function freeptr_outside_object() instead. Also add another helper
function get_info_end() to return the end of info block (inuse + free
pointer if not overlapping with object).
Fixes: 3202fa62fb ("slub: relocate freelist pointer to middle of object")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Rafael Aquini <aquini@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Vitaly Nikolenko <vnik@duasynt.com>
Cc: Silvio Cesare <silvio.cesare@gmail.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Markus Elfring <Markus.Elfring@web.de>
Cc: Changbin Du <changbin.du@gmail.com>
Link: http://lkml.kernel.org/r/20200429135328.26976-1-longman@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 09ef5283fd ]
On passing requirement to vm_unmapped_area, arch_get_unmapped_area and
arch_get_unmapped_area_topdown did not set align_offset. Internally on
both unmapped_area and unmapped_area_topdown, if info->align_mask is 0,
then info->align_offset was meaningless.
But commit df529cabb7 ("mm: mmap: add trace point of
vm_unmapped_area") always prints info->align_offset even though it is
uninitialized.
Fix this uninitialized value issue by setting it to 0 explicitly.
Before:
vm_unmapped_area: addr=0x755b155000 err=0 total_vm=0x15aaf0 flags=0x1 len=0x109000 lo=0x8000 hi=0x75eed48000 mask=0x0 ofs=0x4022
After:
vm_unmapped_area: addr=0x74a4ca1000 err=0 total_vm=0x168ab1 flags=0x1 len=0x9000 lo=0x8000 hi=0x753d94b000 mask=0x0 ofs=0x0
Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michel Lespinasse <walken@google.com>
Cc: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20200409094035.19457-1-jaewon31.kim@samsung.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 5644e1fbbf ]
pgdat->kswapd_classzone_idx could be accessed concurrently in
wakeup_kswapd(). Plain writes and reads without any lock protection
result in data races. Fix them by adding a pair of READ|WRITE_ONCE() as
well as saving a branch (compilers might well optimize the original code
in an unintentional way anyway). While at it, also take care of
pgdat->kswapd_order and non-kswapd threads in allow_direct_reclaim(). The
data races were reported by KCSAN,
BUG: KCSAN: data-race in wakeup_kswapd / wakeup_kswapd
write to 0xffff9f427ffff2dc of 4 bytes by task 7454 on cpu 13:
wakeup_kswapd+0xf1/0x400
wakeup_kswapd at mm/vmscan.c:3967
wake_all_kswapds+0x59/0xc0
wake_all_kswapds at mm/page_alloc.c:4241
__alloc_pages_slowpath+0xdcc/0x1290
__alloc_pages_slowpath at mm/page_alloc.c:4512
__alloc_pages_nodemask+0x3bb/0x450
alloc_pages_vma+0x8a/0x2c0
do_anonymous_page+0x16e/0x6f0
__handle_mm_fault+0xcd5/0xd40
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
1 lock held by mtest01/7454:
#0: ffff9f425afe8808 (&mm->mmap_sem#2){++++}, at:
do_page_fault+0x143/0x6f9
do_user_addr_fault at arch/x86/mm/fault.c:1405
(inlined by) do_page_fault at arch/x86/mm/fault.c:1539
irq event stamp: 6944085
count_memcg_event_mm+0x1a6/0x270
count_memcg_event_mm+0x119/0x270
__do_softirq+0x34c/0x57c
irq_exit+0xa2/0xc0
read to 0xffff9f427ffff2dc of 4 bytes by task 7472 on cpu 38:
wakeup_kswapd+0xc8/0x400
wake_all_kswapds+0x59/0xc0
__alloc_pages_slowpath+0xdcc/0x1290
__alloc_pages_nodemask+0x3bb/0x450
alloc_pages_vma+0x8a/0x2c0
do_anonymous_page+0x16e/0x6f0
__handle_mm_fault+0xcd5/0xd40
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
1 lock held by mtest01/7472:
#0: ffff9f425a9ac148 (&mm->mmap_sem#2){++++}, at:
do_page_fault+0x143/0x6f9
irq event stamp: 6793561
count_memcg_event_mm+0x1a6/0x270
count_memcg_event_mm+0x119/0x270
__do_softirq+0x34c/0x57c
irq_exit+0xa2/0xc0
BUG: KCSAN: data-race in kswapd / wakeup_kswapd
write to 0xffff90973ffff2dc of 4 bytes by task 820 on cpu 6:
kswapd+0x27c/0x8d0
kthread+0x1e0/0x200
ret_from_fork+0x27/0x50
read to 0xffff90973ffff2dc of 4 bytes by task 6299 on cpu 0:
wakeup_kswapd+0xf3/0x450
wake_all_kswapds+0x59/0xc0
__alloc_pages_slowpath+0xdcc/0x1290
__alloc_pages_nodemask+0x3bb/0x450
alloc_pages_vma+0x8a/0x2c0
do_anonymous_page+0x170/0x700
__handle_mm_fault+0xc9f/0xd00
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Link: http://lkml.kernel.org/r/1582749472-5171-1-git-send-email-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 218209487c ]
si->inuse_pages could be accessed concurrently as noticed by KCSAN,
write to 0xffff98b00ebd04dc of 4 bytes by task 82262 on cpu 92:
swap_range_free+0xbe/0x230
swap_range_free at mm/swapfile.c:719
swapcache_free_entries+0x1be/0x250
free_swap_slot+0x1c8/0x220
__swap_entry_free.constprop.19+0xa3/0xb0
free_swap_and_cache+0x53/0xa0
unmap_page_range+0x7e0/0x1ce0
unmap_single_vma+0xcd/0x170
unmap_vmas+0x18b/0x220
exit_mmap+0xee/0x220
mmput+0xe7/0x240
do_exit+0x598/0xfd0
do_group_exit+0x8b/0x180
get_signal+0x293/0x13d0
do_signal+0x37/0x5d0
prepare_exit_to_usermode+0x1b7/0x2c0
ret_from_intr+0x32/0x42
read to 0xffff98b00ebd04dc of 4 bytes by task 82499 on cpu 46:
try_to_unuse+0x86b/0xc80
try_to_unuse at mm/swapfile.c:2185
__x64_sys_swapoff+0x372/0xd40
do_syscall_64+0x91/0xb05
entry_SYSCALL_64_after_hwframe+0x49/0xbe
The plain reads in try_to_unuse() are outside si->lock critical section
which result in data races that could be dangerous to be used in a loop.
Fix them by adding READ_ONCE().
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/1582578903-29294-1-git-send-email-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit faffdfa04f ]
Mount failure issue happens under the scenario: Application forked dozens
of threads to mount the same number of cramfs images separately in docker,
but several mounts failed with high probability. Mount failed due to the
checking result of the page(read from the superblock of loop dev) is not
uptodate after wait_on_page_locked(page) returned in function cramfs_read:
wait_on_page_locked(page);
if (!PageUptodate(page)) {
...
}
The reason of the checking result of the page not uptodate: systemd-udevd
read the loopX dev before mount, because the status of loopX is Lo_unbound
at this time, so loop_make_request directly trigger the calling of io_end
handler end_buffer_async_read, which called SetPageError(page). So It
caused the page can't be set to uptodate in function
end_buffer_async_read:
if(page_uptodate && !PageError(page)) {
SetPageUptodate(page);
}
Then mount operation is performed, it used the same page which is just
accessed by systemd-udevd above, Because this page is not uptodate, it
will launch a actual read via submit_bh, then wait on this page by calling
wait_on_page_locked(page). When the I/O of the page done, io_end handler
end_buffer_async_read is called, because no one cleared the page
error(during the whole read path of mount), which is caused by
systemd-udevd reading, so this page is still in "PageError" status, which
can't be set to uptodate in function end_buffer_async_read, then caused
mount failure.
But sometimes mount succeed even through systemd-udeved read loopX dev
just before, The reason is systemd-udevd launched other loopX read just
between step 3.1 and 3.2, the steps as below:
1, loopX dev default status is Lo_unbound;
2, systemd-udved read loopX dev (page is set to PageError);
3, mount operation
1) set loopX status to Lo_bound;
==>systemd-udevd read loopX dev<==
2) read loopX dev(page has no error)
3) mount succeed
As the loopX dev status is set to Lo_bound after step 3.1, so the other
loopX dev read by systemd-udevd will go through the whole I/O stack, part
of the call trace as below:
SYS_read
vfs_read
do_sync_read
blkdev_aio_read
generic_file_aio_read
do_generic_file_read:
ClearPageError(page);
mapping->a_ops->readpage(filp, page);
here, mapping->a_ops->readpage() is blkdev_readpage. In latest kernel,
some function name changed, the call trace as below:
blkdev_read_iter
generic_file_read_iter
generic_file_buffered_read:
/*
* A previous I/O error may have been due to temporary
* failures, eg. mutipath errors.
* Pg_error will be set again if readpage fails.
*/
ClearPageError(page);
/* Start the actual read. The read will unlock the page*/
error=mapping->a_ops->readpage(flip, page);
We can see ClearPageError(page) is called before the actual read,
then the read in step 3.2 succeed.
This patch is to add the calling of ClearPageError just before the actual
read of read path of cramfs mount. Without the patch, the call trace as
below when performing cramfs mount:
do_mount
cramfs_read
cramfs_blkdev_read
read_cache_page
do_read_cache_page:
filler(data, page);
or
mapping->a_ops->readpage(data, page);
With the patch, the call trace as below when performing mount:
do_mount
cramfs_read
cramfs_blkdev_read
read_cache_page:
do_read_cache_page:
ClearPageError(page); <== new add
filler(data, page);
or
mapping->a_ops->readpage(data, page);
With the patch, mount operation trigger the calling of
ClearPageError(page) before the actual read, the page has no error if no
additional page error happen when I/O done.
Signed-off-by: Xianting Tian <xianting_tian@126.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Cc: <yubin@h3c.com>
Link: http://lkml.kernel.org/r/1583318844-22971-1-git-send-email-xianting_tian@126.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit b0d14fc43d ]
Clang warns:
mm/kmemleak.c:1955:28: warning: array comparison always evaluates to a constant [-Wtautological-compare]
if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata)
^
mm/kmemleak.c:1955:60: warning: array comparison always evaluates to a constant [-Wtautological-compare]
if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata)
These are not true arrays, they are linker defined symbols, which are just
addresses. Using the address of operator silences the warning and does
not change the resulting assembly with either clang/ld.lld or gcc/ld
(tested with diff + objdump -Dr).
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/895
Link: http://lkml.kernel.org/r/20200220051551.44000-1-natechancellor@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c3e5ea6ee5 ]
Jeff Moyer has reported that one of xfstests triggers a warning when run
on DAX-enabled filesystem:
WARNING: CPU: 76 PID: 51024 at mm/memory.c:2317 wp_page_copy+0xc40/0xd50
...
wp_page_copy+0x98c/0xd50 (unreliable)
do_wp_page+0xd8/0xad0
__handle_mm_fault+0x748/0x1b90
handle_mm_fault+0x120/0x1f0
__do_page_fault+0x240/0xd70
do_page_fault+0x38/0xd0
handle_page_fault+0x10/0x30
The warning happens on failed __copy_from_user_inatomic() which tries to
copy data into a CoW page.
This happens because of race between MADV_DONTNEED and CoW page fault:
CPU0 CPU1
handle_mm_fault()
do_wp_page()
wp_page_copy()
do_wp_page()
madvise(MADV_DONTNEED)
zap_page_range()
zap_pte_range()
ptep_get_and_clear_full()
<TLB flush>
__copy_from_user_inatomic()
sees empty PTE and fails
WARN_ON_ONCE(1)
clear_page()
The solution is to re-try __copy_from_user_inatomic() under PTL after
checking that PTE is matches the orig_pte.
The second copy attempt can still fail, like due to non-readable PTE, but
there's nothing reasonable we can do about, except clearing the CoW page.
Reported-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Jeff Moyer <jmoyer@redhat.com>
Cc: <stable@vger.kernel.org>
Cc: Justin He <Justin.He@arm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Link: http://lkml.kernel.org/r/20200218154151.13349-1-kirill.shutemov@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c02a98753e ]
If walk_pte_range() is called with a 'end' argument that is beyond the
last page of memory (e.g. ~0UL) then the comparison between 'addr' and
'end' will always fail and the loop will be infinite. Instead change the
comparison to >= while accounting for overflow.
Link: http://lkml.kernel.org/r/20191218162402.45610-15-steven.price@arm.com
Signed-off-by: Steven Price <steven.price@arm.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zong Li <zong.li@sifive.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 10c8d69f31 ]
If seq_file .next fuction does not change position index, read after
some lseek can generate unexpected output.
In Aug 2018 NeilBrown noticed commit 1f4aace60b ("fs/seq_file.c:
simplify seq_file iteration code and interface") "Some ->next functions
do not increment *pos when they return NULL... Note that such ->next
functions are buggy and should be fixed. A simple demonstration is
dd if=/proc/swaps bs=1000 skip=1
Choose any block size larger than the size of /proc/swaps. This will
always show the whole last line of /proc/swaps"
Described problem is still actual. If you make lseek into middle of
last output line following read will output end of last line and whole
last line once again.
$ dd if=/proc/swaps bs=1 # usual output
Filename Type Size Used Priority
/dev/dm-0 partition 4194812 97536 -2
104+0 records in
104+0 records out
104 bytes copied
$ dd if=/proc/swaps bs=40 skip=1 # last line was generated twice
dd: /proc/swaps: cannot skip to specified offset
v/dm-0 partition 4194812 97536 -2
/dev/dm-0 partition 4194812 97536 -2
3+1 records in
3+1 records out
131 bytes copied
https://bugzilla.kernel.org/show_bug.cgi?id=206283
Link: http://lkml.kernel.org/r/bd8cfd7b-ac95-9b91-f9e7-e8438bd5047d@virtuozzo.com
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jann Horn <jannh@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 83d116c530 ]
When we tested pmdk unit test [1] vmmalloc_fork TEST3 on arm64 guest, there
will be a double page fault in __copy_from_user_inatomic of cow_user_page.
To reproduce the bug, the cmd is as follows after you deployed everything:
make -C src/test/vmmalloc_fork/ TEST_TIME=60m check
Below call trace is from arm64 do_page_fault for debugging purpose:
[ 110.016195] Call trace:
[ 110.016826] do_page_fault+0x5a4/0x690
[ 110.017812] do_mem_abort+0x50/0xb0
[ 110.018726] el1_da+0x20/0xc4
[ 110.019492] __arch_copy_from_user+0x180/0x280
[ 110.020646] do_wp_page+0xb0/0x860
[ 110.021517] __handle_mm_fault+0x994/0x1338
[ 110.022606] handle_mm_fault+0xe8/0x180
[ 110.023584] do_page_fault+0x240/0x690
[ 110.024535] do_mem_abort+0x50/0xb0
[ 110.025423] el0_da+0x20/0x24
The pte info before __copy_from_user_inatomic is (PTE_AF is cleared):
[ffff9b007000] pgd=000000023d4f8003, pud=000000023da9b003,
pmd=000000023d4b3003, pte=360000298607bd3
As told by Catalin: "On arm64 without hardware Access Flag, copying from
user will fail because the pte is old and cannot be marked young. So we
always end up with zeroed page after fork() + CoW for pfn mappings. we
don't always have a hardware-managed access flag on arm64."
This patch fixes it by calling pte_mkyoung. Also, the parameter is
changed because vmf should be passed to cow_user_page()
Add a WARN_ON_ONCE when __copy_from_user_inatomic() returns error
in case there can be some obscure use-case (by Kirill).
[1] https://github.com/pmem/pmdk/tree/master/src/test/vmmalloc_fork
Signed-off-by: Jia He <justin.he@arm.com>
Reported-by: Yibo Cai <Yibo.Cai@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit e3336cab25 upstream.
We've met softlockup with "CONFIG_PREEMPT_NONE=y", when the target memcg
doesn't have any reclaimable memory.
It can be easily reproduced as below:
watchdog: BUG: soft lockup - CPU#0 stuck for 111s![memcg_test:2204]
CPU: 0 PID: 2204 Comm: memcg_test Not tainted 5.9.0-rc2+ #12
Call Trace:
shrink_lruvec+0x49f/0x640
shrink_node+0x2a6/0x6f0
do_try_to_free_pages+0xe9/0x3e0
try_to_free_mem_cgroup_pages+0xef/0x1f0
try_charge+0x2c1/0x750
mem_cgroup_charge+0xd7/0x240
__add_to_page_cache_locked+0x2fd/0x370
add_to_page_cache_lru+0x4a/0xc0
pagecache_get_page+0x10b/0x2f0
filemap_fault+0x661/0xad0
ext4_filemap_fault+0x2c/0x40
__do_fault+0x4d/0xf9
handle_mm_fault+0x1080/0x1790
It only happens on our 1-vcpu instances, because there's no chance for
oom reaper to run to reclaim the to-be-killed process.
Add a cond_resched() at the upper shrink_node_memcgs() to solve this
issue, this will mean that we will get a scheduling point for each memcg
in the reclaimed hierarchy without any dependency on the reclaimable
memory in that memcg thus making it more predictable.
Suggested-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Xunlei Pang <xlpang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Chris Down <chris@chrisdown.name>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: http://lkml.kernel.org/r/1598495549-67324-1-git-send-email-xlpang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Julius Hemanth Pitti <jpitti@cisco.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit ec0abae6dc ]
A migrating transparent huge page has to already be unmapped. Otherwise,
the page could be modified while it is being copied to a new page and data
could be lost. The function __split_huge_pmd() checks for a PMD migration
entry before calling __split_huge_pmd_locked() leading one to think that
__split_huge_pmd_locked() can handle splitting a migrating PMD.
However, the code always increments the page->_mapcount and adjusts the
memory control group accounting assuming the page is mapped.
Also, if the PMD entry is a migration PMD entry, the call to
is_huge_zero_pmd(*pmd) is incorrect because it calls pmd_pfn(pmd) instead
of migration_entry_to_pfn(pmd_to_swp_entry(pmd)). Fix these problems by
checking for a PMD migration entry.
Fixes: 84c3fc4e9c ("mm: thp: check pmd migration entry in common path")
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Bharata B Rao <bharata@linux.ibm.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org> [4.14+]
Link: https://lkml.kernel.org/r/20200903183140.19055-1-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 9683182612 upstream.
There is a race during page offline that can lead to infinite loop:
a page never ends up on a buddy list and __offline_pages() keeps
retrying infinitely or until a termination signal is received.
Thread#1 - a new process:
load_elf_binary
begin_new_exec
exec_mmap
mmput
exit_mmap
tlb_finish_mmu
tlb_flush_mmu
release_pages
free_unref_page_list
free_unref_page_prepare
set_pcppage_migratetype(page, migratetype);
// Set page->index migration type below MIGRATE_PCPTYPES
Thread#2 - hot-removes memory
__offline_pages
start_isolate_page_range
set_migratetype_isolate
set_pageblock_migratetype(page, MIGRATE_ISOLATE);
Set migration type to MIGRATE_ISOLATE-> set
drain_all_pages(zone);
// drain per-cpu page lists to buddy allocator.
Thread#1 - continue
free_unref_page_commit
migratetype = get_pcppage_migratetype(page);
// get old migration type
list_add(&page->lru, &pcp->lists[migratetype]);
// add new page to already drained pcp list
Thread#2
Never drains pcp again, and therefore gets stuck in the loop.
The fix is to try to drain per-cpu lists again after
check_pages_isolated_cb() fails.
Fixes: c52e75935f ("mm: remove extra drain pages on pcp list")
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200903140032.380431-1-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20200904151448.100489-2-pasha.tatashin@soleen.com
Link: http://lkml.kernel.org/r/20200904070235.GA15277@dhcp22.suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b3b33d3c43 upstream.
Variable populated, which is a member of struct pcpu_chunk, is used as a
unit of size of unsigned long.
However, size of populated is miscounted. So, I fix this minor part.
Fixes: 8ab16c43ea ("percpu: change the number of pages marked in the first_chunk pop bitmap")
Cc: <stable@vger.kernel.org> # 4.14+
Signed-off-by: Sunghyun Jin <mcsmonk@gmail.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e5a59d308f upstream.
collapse_file() in khugepaged passes PAGE_SIZE as the number of pages to
be read to page_cache_sync_readahead(). The intent was probably to read
a single page. Fix it to use the number of pages to the end of the
window instead.
Fixes: 99cb0dbd47 ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Yang Shi <shy828301@gmail.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Eric Biggers <ebiggers@google.com>
Link: https://lkml.kernel.org/r/20200903140844.14194-2-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 17743798d8 upstream.
There is a race between the assignment of `table->data` and write value
to the pointer of `table->data` in the __do_proc_doulongvec_minmax() on
the other thread.
CPU0: CPU1:
proc_sys_write
hugetlb_sysctl_handler proc_sys_call_handler
hugetlb_sysctl_handler_common hugetlb_sysctl_handler
table->data = &tmp; hugetlb_sysctl_handler_common
table->data = &tmp;
proc_doulongvec_minmax
do_proc_doulongvec_minmax sysctl_head_finish
__do_proc_doulongvec_minmax unuse_table
i = table->data;
*i = val; // corrupt CPU1's stack
Fix this by duplicating the `table`, and only update the duplicate of
it. And introduce a helper of proc_hugetlb_doulongvec_minmax() to
simplify the code.
The following oops was seen:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
Code: Bad RIP value.
...
Call Trace:
? set_max_huge_pages+0x3da/0x4f0
? alloc_pool_huge_page+0x150/0x150
? proc_doulongvec_minmax+0x46/0x60
? hugetlb_sysctl_handler_common+0x1c7/0x200
? nr_hugepages_store+0x20/0x20
? copy_fd_bitmaps+0x170/0x170
? hugetlb_sysctl_handler+0x1e/0x20
? proc_sys_call_handler+0x2f1/0x300
? unregister_sysctl_table+0xb0/0xb0
? __fd_install+0x78/0x100
? proc_sys_write+0x14/0x20
? __vfs_write+0x4d/0x90
? vfs_write+0xef/0x240
? ksys_write+0xc0/0x160
? __ia32_sys_read+0x50/0x50
? __close_fd+0x129/0x150
? __x64_sys_write+0x43/0x50
? do_syscall_64+0x6c/0x200
? entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: e5ff215941 ("hugetlb: multiple hstates for multiple page sizes")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20200828031146.43035-1-songmuchun@bytedance.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit dc07a728d4 upstream.
Commit 52f2347808 ("mm/slub.c: fix corrupted freechain in
deactivate_slab()") suffered an update when picked up from LKML [1].
Specifically, relocating 'freelist = NULL' into 'freelist_corrupted()'
created a no-op statement. Fix it by sticking to the behavior intended
in the original patch [1]. In addition, make freelist_corrupted()
immune to passing NULL instead of &freelist.
The issue has been spotted via static analysis and code review.
[1] https://lore.kernel.org/linux-mm/20200331031450.12182-1-dongli.zhang@oracle.com/
Fixes: 52f2347808 ("mm/slub.c: fix corrupted freechain in deactivate_slab()")
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dongli Zhang <dongli.zhang@oracle.com>
Cc: Joe Jin <joe.jin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200824130643.10291-1-erosca@de.adit-jv.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit e47110e905 ]
Like zap_pte_range add cond_resched so that we can avoid softlockups as
reported below. On non-preemptible kernel with large I/O map region (like
the one we get when using persistent memory with sector mode), an unmap of
the namespace can report below softlockups.
22724.027334] watchdog: BUG: soft lockup - CPU#49 stuck for 23s! [ndctl:50777]
NIP [c0000000000dc224] plpar_hcall+0x38/0x58
LR [c0000000000d8898] pSeries_lpar_hpte_invalidate+0x68/0xb0
Call Trace:
flush_hash_page+0x114/0x200
hpte_need_flush+0x2dc/0x540
vunmap_page_range+0x538/0x6f0
free_unmap_vmap_area+0x30/0x70
remove_vm_area+0xfc/0x140
__vunmap+0x68/0x270
__iounmap.part.0+0x34/0x60
memunmap+0x54/0x70
release_nodes+0x28c/0x300
device_release_driver_internal+0x16c/0x280
unbind_store+0x124/0x170
drv_attr_store+0x44/0x60
sysfs_kf_write+0x64/0x90
kernfs_fop_write+0x1b0/0x290
__vfs_write+0x3c/0x70
vfs_write+0xd8/0x260
ksys_write+0xdc/0x130
system_call+0x5c/0x70
Reported-by: Harish Sriram <harish@linux.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200807075933.310240-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 3a5139f1c5 ]
The routine cma_init_reserved_areas is designed to activate all
reserved cma areas. It quits when it first encounters an error.
This can leave some areas in a state where they are reserved but
not activated. There is no feedback to code which performed the
reservation. Attempting to allocate memory from areas in such a
state will result in a BUG.
Modify cma_init_reserved_areas to always attempt to activate all
areas. The called routine, cma_activate_area is responsible for
leaving the area in a valid state. No one is making active use
of returned error codes, so change the routine to void.
How to reproduce: This example uses kernelcore, hugetlb and cma
as an easy way to reproduce. However, this is a more general cma
issue.
Two node x86 VM 16GB total, 8GB per node
Kernel command line parameters, kernelcore=4G hugetlb_cma=8G
Related boot time messages,
hugetlb_cma: reserve 8192 MiB, up to 4096 MiB per node
cma: Reserved 4096 MiB at 0x0000000100000000
hugetlb_cma: reserved 4096 MiB on node 0
cma: Reserved 4096 MiB at 0x0000000300000000
hugetlb_cma: reserved 4096 MiB on node 1
cma: CMA area hugetlb could not be activated
# echo 8 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
...
Call Trace:
bitmap_find_next_zero_area_off+0x51/0x90
cma_alloc+0x1a5/0x310
alloc_fresh_huge_page+0x78/0x1a0
alloc_pool_huge_page+0x6f/0xf0
set_max_huge_pages+0x10c/0x250
nr_hugepages_store_common+0x92/0x120
? __kmalloc+0x171/0x270
kernfs_fop_write+0xc1/0x1a0
vfs_write+0xc7/0x1f0
ksys_write+0x5f/0xe0
do_syscall_64+0x4d/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: c64be2bb1c ("drivers: add Contiguous Memory Allocator")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Barry Song <song.bao.hua@hisilicon.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200730163123.6451-1-mike.kravetz@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 38cf307c1f ]
For SMP systems using IPI based TLB invalidation, looking at
current->active_mm is entirely reasonable. This then presents the
following race condition:
CPU0 CPU1
flush_tlb_mm(mm) use_mm(mm)
<send-IPI>
tsk->active_mm = mm;
<IPI>
if (tsk->active_mm == mm)
// flush TLBs
</IPI>
switch_mm(old_mm,mm,tsk);
Where it is possible the IPI flushed the TLBs for @old_mm, not @mm,
because the IPI lands before we actually switched.
Avoid this by disabling IRQs across changing ->active_mm and
switch_mm().
Of the (SMP) architectures that have IPI based TLB invalidate:
Alpha - checks active_mm
ARC - ASID specific
IA64 - checks active_mm
MIPS - ASID specific flush
OpenRISC - shoots down world
PARISC - shoots down world
SH - ASID specific
SPARC - ASID specific
x86 - N/A
xtensa - checks active_mm
So at the very least Alpha, IA64 and Xtensa are suspect.
On top of this, for scheduler consistency we need at least preemption
disabled across changing tsk->mm and doing switch_mm(), which is
currently provided by task_lock(), but that's not sufficient for
PREEMPT_RT.
[akpm@linux-foundation.org: add comment]
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Jann Horn <jannh@google.com>
Cc: Will Deacon <will@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200721154106.GE10769@hirez.programming.kicks-ass.net
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 4a93025cbe ]
Especially with memory hotplug, we can have offline sections (with a
garbage memmap) and overlapping zones. We have to make sure to only touch
initialized memmaps (online sections managed by the buddy) and that the
zone matches, to not move pages between zones.
To test if this can actually happen, I added a simple
BUG_ON(page_zone(page_i) != page_zone(page_j));
right before the swap. When hotplugging a 256M DIMM to a 4G x86-64 VM and
onlining the first memory block "online_movable" and the second memory
block "online_kernel", it will trigger the BUG, as both zones (NORMAL and
MOVABLE) overlap.
This might result in all kinds of weird situations (e.g., double
allocations, list corruptions, unmovable allocations ending up in the
movable zone).
Fixes: e900a918b0 ("mm: shuffle initial free memory to improve memory-side-cache utilization")
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org> [5.2+]
Link: http://lkml.kernel.org/r/20200624094741.9918-2-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 75802ca663 upstream.
This is found by code observation only.
Firstly, the worst case scenario should assume the whole range was covered
by pmd sharing. The old algorithm might not work as expected for ranges
like (1g-2m, 1g+2m), where the adjusted range should be (0, 1g+2m) but the
expected range should be (0, 2g).
Since at it, remove the loop since it should not be required. With that,
the new code should be faster too when the invalidating range is huge.
Mike said:
: With range (1g-2m, 1g+2m) within a vma (0, 2g) the existing code will only
: adjust to (0, 1g+2m) which is incorrect.
:
: We should cc stable. The original reason for adjusting the range was to
: prevent data corruption (getting wrong page). Since the range is not
: always adjusted correctly, the potential for corruption still exists.
:
: However, I am fairly confident that adjust_range_if_pmd_sharing_possible
: is only gong to be called in two cases:
:
: 1) for a single page
: 2) for range == entire vma
:
: In those cases, the current code should produce the correct results.
:
: To be safe, let's just cc stable.
Fixes: 017b1660df ("mm: migration: fix migration of huge PMD shared pages")
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200730201636.74778-1-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 88e8ac11d2 upstream.
The following race is observed with the repeated online, offline and a
delay between two successive online of memory blocks of movable zone.
P1 P2
Online the first memory block in
the movable zone. The pcp struct
values are initialized to default
values,i.e., pcp->high = 0 &
pcp->batch = 1.
Allocate the pages from the
movable zone.
Try to Online the second memory
block in the movable zone thus it
entered the online_pages() but yet
to call zone_pcp_update().
This process is entered into
the exit path thus it tries
to release the order-0 pages
to pcp lists through
free_unref_page_commit().
As pcp->high = 0, pcp->count = 1
proceed to call the function
free_pcppages_bulk().
Update the pcp values thus the
new pcp values are like, say,
pcp->high = 378, pcp->batch = 63.
Read the pcp's batch value using
READ_ONCE() and pass the same to
free_pcppages_bulk(), pcp values
passed here are, batch = 63,
count = 1.
Since num of pages in the pcp
lists are less than ->batch,
then it will stuck in
while(list_empty(list)) loop
with interrupts disabled thus
a core hung.
Avoid this by ensuring free_pcppages_bulk() is called with proper count of
pcp list pages.
The mentioned race is some what easily reproducible without [1] because
pcp's are not updated for the first memory block online and thus there is
a enough race window for P2 between alloc+free and pcp struct values
update through onlining of second memory block.
With [1], the race still exists but it is very narrow as we update the pcp
struct values for the first memory block online itself.
This is not limited to the movable zone, it could also happen in cases
with the normal zone (e.g., hotplug to a node that only has DMA memory, or
no other memory yet).
[1]: https://patchwork.kernel.org/patch/11696389/
Fixes: 5f8dcc2121 ("page-allocator: split per-cpu list into one-list-per-migrate-type")
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Cc: <stable@vger.kernel.org> [2.6+]
Link: http://lkml.kernel.org/r/1597150703-19003-1-git-send-email-charante@codeaurora.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e08d3fdfe2 upstream.
The lowmem_reserve arrays provide a means of applying pressure against
allocations from lower zones that were targeted at higher zones. Its
values are a function of the number of pages managed by higher zones and
are assigned by a call to the setup_per_zone_lowmem_reserve() function.
The function is initially called at boot time by the function
init_per_zone_wmark_min() and may be called later by accesses of the
/proc/sys/vm/lowmem_reserve_ratio sysctl file.
The function init_per_zone_wmark_min() was moved up from a module_init to
a core_initcall to resolve a sequencing issue with khugepaged.
Unfortunately this created a sequencing issue with CMA page accounting.
The CMA pages are added to the managed page count of a zone when
cma_init_reserved_areas() is called at boot also as a core_initcall. This
makes it uncertain whether the CMA pages will be added to the managed page
counts of their zones before or after the call to
init_per_zone_wmark_min() as it becomes dependent on link order. With the
current link order the pages are added to the managed count after the
lowmem_reserve arrays are initialized at boot.
This means the lowmem_reserve values at boot may be lower than the values
used later if /proc/sys/vm/lowmem_reserve_ratio is accessed even if the
ratio values are unchanged.
In many cases the difference is not significant, but for example
an ARM platform with 1GB of memory and the following memory layout
cma: Reserved 256 MiB at 0x0000000030000000
Zone ranges:
DMA [mem 0x0000000000000000-0x000000002fffffff]
Normal empty
HighMem [mem 0x0000000030000000-0x000000003fffffff]
would result in 0 lowmem_reserve for the DMA zone. This would allow
userspace to deplete the DMA zone easily.
Funnily enough
$ cat /proc/sys/vm/lowmem_reserve_ratio
would fix up the situation because as a side effect it forces
setup_per_zone_lowmem_reserve.
This commit breaks the link order dependency by invoking
init_per_zone_wmark_min() as a postcore_initcall so that the CMA pages
have the chance to be properly accounted in their zone(s) and allowing
the lowmem_reserve arrays to receive consistent values.
Fixes: bc22af74f2 ("mm: update min_free_kbytes from khugepaged after core initialization")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/1597423766-27849-1-git-send-email-opendmb@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit f3f99d63a8 ]
syzbot crashes on the VM_BUG_ON_MM(khugepaged_test_exit(mm), mm) in
__khugepaged_enter(): yes, when one thread is about to dump core, has set
core_state, and is waiting for others, another might do something calling
__khugepaged_enter(), which now crashes because I lumped the core_state
test (known as "mmget_still_valid") into khugepaged_test_exit(). I still
think it's best to lump them together, so just in this exceptional case,
check mm->mm_users directly instead of khugepaged_test_exit().
Fixes: bbe98f9cad ("khugepaged: khugepaged_test_exit() check mmget_still_valid()")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Yang Shi <shy828301@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: <stable@vger.kernel.org> [4.8+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008141503370.18085@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit bbe98f9cad ]
Move collapse_huge_page()'s mmget_still_valid() check into
khugepaged_test_exit() itself. collapse_huge_page() is used for anon THP
only, and earned its mmget_still_valid() check because it inserts a huge
pmd entry in place of the page table's pmd entry; whereas
collapse_file()'s retract_page_tables() or collapse_pte_mapped_thp()
merely clears the page table's pmd entry. But core dumping without mmap
lock must have been as open to mistaking a racily cleared pmd entry for a
page table at physical page 0, as exit_mmap() was. And we certainly have
no interest in mapping as a THP once dumping core.
Fixes: 59ea6d06cf ("coredump: fix race condition between collapse_huge_page() and core dumping")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org> [4.8+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021217020.27773@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 18e77600f7 upstream.
Only once have I seen this scenario (and forgot even to notice what forced
the eventual crash): a sequence of "BUG: Bad page map" alerts from
vm_normal_page(), from zap_pte_range() servicing exit_mmap();
pmd:00000000, pte values corresponding to data in physical page 0.
The pte mappings being zapped in this case were supposed to be from a huge
page of ext4 text (but could as well have been shmem): my belief is that
it was racing with collapse_file()'s retract_page_tables(), found *pmd
pointing to a page table, locked it, but *pmd had become 0 by the time
start_pte was decided.
In most cases, that possibility is excluded by holding mmap lock; but
exit_mmap() proceeds without mmap lock. Most of what's run by khugepaged
checks khugepaged_test_exit() after acquiring mmap lock:
khugepaged_collapse_pte_mapped_thps() and hugepage_vma_revalidate() do so,
for example. But retract_page_tables() did not: fix that.
The fix is for retract_page_tables() to check khugepaged_test_exit(),
after acquiring mmap lock, before doing anything to the page table.
Getting the mmap lock serializes with __mmput(), which briefly takes and
drops it in __khugepaged_exit(); then the khugepaged_test_exit() check on
mm_users makes sure we don't touch the page table once exit_mmap() might
reach it, since exit_mmap() will be proceeding without mmap lock, not
expecting anyone to be racing with it.
Fixes: f3f0e1d215 ("khugepaged: add support of collapse for tmpfs/shmem pages")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: <stable@vger.kernel.org> [4.8+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021215400.27773@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a6f23d14ec upstream.
When workload runs in cgroups that aren't directly below root cgroup and
their parent specifies reclaim protection, it may end up ineffective.
The reason is that propagate_protected_usage() is not called in all
hierarchy up. All the protected usage is incorrectly accumulated in the
workload's parent. This means that siblings_low_usage is overestimated
and effective protection underestimated. Even though it is transitional
phenomenon (uncharge path does correct propagation and fixes the wrong
children_low_usage), it can undermine the intended protection
unexpectedly.
We have noticed this problem while seeing a swap out in a descendant of a
protected memcg (intermediate node) while the parent was conveniently
under its protection limit and the memory pressure was external to that
hierarchy. Michal has pinpointed this down to the wrong
siblings_low_usage which led to the unwanted reclaim.
The fix is simply updating children_low_usage in respective ancestors also
in the charging path.
Fixes: 230671533d ("mm: memory.low hierarchical behavior")
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org> [4.18+]
Link: http://lkml.kernel.org/r/20200803153231.15477-1-mhocko@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 119a5fc161 upstream.
When retract_page_tables() removes a page table to make way for a huge
pmd, it holds huge page lock, i_mmap_lock_write, mmap_write_trylock and
pmd lock; but when collapse_pte_mapped_thp() does the same (to handle the
case when the original mmap_write_trylock had failed), only
mmap_write_trylock and pmd lock are held.
That's not enough. One machine has twice crashed under load, with "BUG:
spinlock bad magic" and GPF on 6b6b6b6b6b6b6b6b. Examining the second
crash, page_vma_mapped_walk_done()'s spin_unlock of pvmw->ptl (serving
page_referenced() on a file THP, that had found a page table at *pmd)
discovers that the page table page and its lock have already been freed by
the time it comes to unlock.
Follow the example of retract_page_tables(), but we only need one of huge
page lock or i_mmap_lock_write to secure against this: because it's the
narrower lock, and because it simplifies collapse_pte_mapped_thp() to know
the hpage earlier, choose to rely on huge page lock here.
Fixes: 27e1f82731 ("khugepaged: enable collapse pmd for pte-mapped THP")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: <stable@vger.kernel.org> [5.4+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021213070.27773@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 723a80dafe upstream.
pmdp_collapse_flush() should be given the start address at which the huge
page is mapped, haddr: it was given addr, which at that point has been
used as a local variable, incremented to the end address of the extent.
Found by source inspection while chasing a hugepage locking bug, which I
then could not explain by this. At first I thought this was very bad;
then saw that all of the page translations that were not flushed would
actually still point to the right pages afterwards, so harmless; then
realized that I know nothing of how different architectures and models
cache intermediate paging structures, so maybe it matters after all -
particularly since the page table concerned is immediately freed.
Much easier to fix than to think about.
Fixes: 27e1f82731 ("khugepaged: enable collapse pmd for pte-mapped THP")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: <stable@vger.kernel.org> [5.4+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021204390.27773@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5c72feee3e upstream.
When handling a page fault, we drop mmap_sem to start async readahead so
that we don't block on IO submission with mmap_sem held. However there's
no point to drop mmap_sem in case readahead is disabled. Handle that case
to avoid pointless dropping of mmap_sem and retrying the fault. This was
actually reported to block mlockall(MCL_CURRENT) indefinitely.
Fixes: 6b4c9f4469 ("filemap: drop the mmap_sem for all blocking operations")
Reported-by: Minchan Kim <minchan@kernel.org>
Reported-by: Robert Stupp <snazy@gmx.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Link: http://lkml.kernel.org/r/20200212101356.30759-1-jack@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: SeongJae Park <sjpark@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 594cced14a upstream.
khugepaged has to drop mmap lock several times while collapsing a page.
The situation can change while the lock is dropped and we need to
re-validate that the VMA is still in place and the PMD is still subject
for collapse.
But we miss one corner case: while collapsing an anonymous pages the VMA
could be replaced with file VMA. If the file VMA doesn't have any
private pages we get NULL pointer dereference:
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
anon_vma_lock_write include/linux/rmap.h:120 [inline]
collapse_huge_page mm/khugepaged.c:1110 [inline]
khugepaged_scan_pmd mm/khugepaged.c:1349 [inline]
khugepaged_scan_mm_slot mm/khugepaged.c:2110 [inline]
khugepaged_do_scan mm/khugepaged.c:2193 [inline]
khugepaged+0x3bba/0x5a10 mm/khugepaged.c:2238
The fix is to make sure that the VMA is anonymous in
hugepage_vma_revalidate(). The helper is only used for collapsing
anonymous pages.
Fixes: 99cb0dbd47 ("mm,thp: add read-only THP support for (non-shmem) FS")
Reported-by: syzbot+ed318e8b790ca72c5ad0@syzkaller.appspotmail.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Yang Shi <yang.shi@linux.alibaba.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200722121439.44328-1-kirill.shutemov@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d38a2b7a9c upstream.
If the kmem_cache refcount is greater than one, we should not mark the
root kmem_cache as dying. If we mark the root kmem_cache dying
incorrectly, the non-root kmem_cache can never be destroyed. It
resulted in memory leak when memcg was destroyed. We can use the
following steps to reproduce.
1) Use kmem_cache_create() to create a new kmem_cache named A.
2) Coincidentally, the kmem_cache A is an alias for kmem_cache B,
so the refcount of B is just increased.
3) Use kmem_cache_destroy() to destroy the kmem_cache A, just
decrease the B's refcount but mark the B as dying.
4) Create a new memory cgroup and alloc memory from the kmem_cache
B. It leads to create a non-root kmem_cache for allocating memory.
5) When destroy the memory cgroup created in the step 4), the
non-root kmem_cache can never be destroyed.
If we repeat steps 4) and 5), this will cause a lot of memory leak. So
only when refcount reach zero, we mark the root kmem_cache as dying.
Fixes: 92ee383f6d ("mm: fix race between kmem_cache destroy, create and deactivate")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200716165103.83462-1-songmuchun@bytedance.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8d22a93510 upstream.
It was hard to keep a test running, moving tasks between memcgs with
move_charge_at_immigrate, while swapping: mem_cgroup_id_get_many()'s
refcount is discovered to be 0 (supposedly impossible), so it is then
forced to REFCOUNT_SATURATED, and after thousands of warnings in quick
succession, the test is at last put out of misery by being OOM killed.
This is because of the way moved_swap accounting was saved up until the
task move gets completed in __mem_cgroup_clear_mc(), deferred from when
mem_cgroup_move_swap_account() actually exchanged old and new ids.
Concurrent activity can free up swap quicker than the task is scanned,
bringing id refcount down 0 (which should only be possible when
offlining).
Just skip that optimization: do that part of the accounting immediately.
Fixes: 615d66c37c ("mm: memcontrol: fix memcg id ref counter on swap charge move")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2007071431050.4726@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 246c320a8c upstream.
VMA with VM_GROWSDOWN or VM_GROWSUP flag set can change their size under
mmap_read_lock(). It can lead to race with __do_munmap():
Thread A Thread B
__do_munmap()
detach_vmas_to_be_unmapped()
mmap_write_downgrade()
expand_downwards()
vma->vm_start = address;
// The VMA now overlaps with
// VMAs detached by the Thread A
// page fault populates expanded part
// of the VMA
unmap_region()
// Zaps pagetables partly
// populated by Thread B
Similar race exists for expand_upwards().
The fix is to avoid downgrading mmap_lock in __do_munmap() if detached
VMAs are next to VM_GROWSDOWN or VM_GROWSUP VMA.
[akpm@linux-foundation.org: s/mmap_sem/mmap_lock/ in comment]
Fixes: dd2283f260 ("mm: mmap: zap pages with read mmap_sem in munmap")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org> [4.20+]
Link: http://lkml.kernel.org/r/20200709105309.42495-1-kirill.shutemov@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b9e20f0da1 upstream.
Hugh reports:
"While stressing compaction, one run oopsed on NULL capc->cc in
__free_one_page()'s task_capc(zone): compact_zone_order() had been
interrupted, and a page was being freed in the return from interrupt.
Though you would not expect it from the source, both gccs I was using
(4.8.1 and 7.5.0) had chosen to compile compact_zone_order() with the
".cc = &cc" implemented by mov %rbx,-0xb0(%rbp) immediately before
callq compact_zone - long after the "current->capture_control =
&capc". An interrupt in between those finds capc->cc NULL (zeroed by
an earlier rep stos).
This could presumably be fixed by a barrier() before setting
current->capture_control in compact_zone_order(); but would also need
more care on return from compact_zone(), in order not to risk leaking
a page captured by interrupt just before capture_control is reset.
Maybe that is the preferable fix, but I felt safer for task_capc() to
exclude the rather surprising possibility of capture at interrupt
time"
I have checked that gcc10 also behaves the same.
The advantage of fix in compact_zone_order() is that we don't add
another test in the page freeing hot path, and that it might prevent
future problems if we stop exposing pointers to uninitialized structures
in current task.
So this patch implements the suggestion for compact_zone_order() with
barrier() (and WRITE_ONCE() to prevent store tearing) for setting
current->capture_control, and prevents page leaking with
WRITE_ONCE/READ_ONCE in the proper order.
Link: http://lkml.kernel.org/r/20200616082649.27173-1-vbabka@suse.cz
Fixes: 5e1f0f098b ("mm, compaction: capture a page under direct compaction")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Hugh Dickins <hughd@google.com>
Suggested-by: Hugh Dickins <hughd@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Li Wang <liwang@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org> [5.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6467552ca6 upstream.
Dan reports:
The patch 5e1f0f098b46: "mm, compaction: capture a page under direct
compaction" from Mar 5, 2019, leads to the following Smatch complaint:
mm/compaction.c:2321 compact_zone_order()
error: we previously assumed 'capture' could be null (see line 2313)
mm/compaction.c
2288 static enum compact_result compact_zone_order(struct zone *zone, int order,
2289 gfp_t gfp_mask, enum compact_priority prio,
2290 unsigned int alloc_flags, int classzone_idx,
2291 struct page **capture)
^^^^^^^
2313 if (capture)
^^^^^^^
Check for NULL
2314 current->capture_control = &capc;
2315
2316 ret = compact_zone(&cc, &capc);
2317
2318 VM_BUG_ON(!list_empty(&cc.freepages));
2319 VM_BUG_ON(!list_empty(&cc.migratepages));
2320
2321 *capture = capc.page;
^^^^^^^^
Unchecked dereference.
2322 current->capture_control = NULL;
2323
In practice this is not an issue, as the only caller path passes non-NULL
capture:
__alloc_pages_direct_compact()
struct page *page = NULL;
try_to_compact_pages(capture = &page);
compact_zone_order(capture = capture);
So let's remove the unnecessary check, which should also make Smatch happy.
Fixes: 5e1f0f098b ("mm, compaction: capture a page under direct compaction")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Link: http://lkml.kernel.org/r/18b0df3c-0589-d96c-23fa-040798fee187@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit a68ee05739 ]
There is no need to copy SLUB_STATS items from root memcg cache to new
memcg cache copies. Doing so could result in stack overruns because the
store function only accepts 0 to clear the stat and returns an error for
everything else while the show method would print out the whole stat.
Then, the mismatch of the lengths returns from show and store methods
happens in memcg_propagate_slab_attrs():
else if (root_cache->max_attr_size < ARRAY_SIZE(mbuf))
buf = mbuf;
max_attr_size is only 2 from slab_attr_store(), then, it uses mbuf[64]
in show_stat() later where a bounch of sprintf() would overrun the stack
variable. Fix it by always allocating a page of buffer to be used in
show_stat() if SLUB_STATS=y which should only be used for debug purpose.
# echo 1 > /sys/kernel/slab/fs_cache/shrink
BUG: KASAN: stack-out-of-bounds in number+0x421/0x6e0
Write of size 1 at addr ffffc900256cfde0 by task kworker/76:0/53251
Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019
Workqueue: memcg_kmem_cache memcg_kmem_cache_create_func
Call Trace:
number+0x421/0x6e0
vsnprintf+0x451/0x8e0
sprintf+0x9e/0xd0
show_stat+0x124/0x1d0
alloc_slowpath_show+0x13/0x20
__kmem_cache_create+0x47a/0x6b0
addr ffffc900256cfde0 is located in stack of task kworker/76:0/53251 at offset 0 in frame:
process_one_work+0x0/0xb90
this frame has 1 object:
[32, 72) 'lockdep_map'
Memory state around the buggy address:
ffffc900256cfc80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffc900256cfd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc900256cfd80: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
^
ffffc900256cfe00: 00 00 00 00 00 f2 f2 f2 00 00 00 00 00 00 00 00
ffffc900256cfe80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: __kmem_cache_create+0x6ac/0x6b0
Workqueue: memcg_kmem_cache memcg_kmem_cache_create_func
Call Trace:
__kmem_cache_create+0x6ac/0x6b0
Fixes: 107dab5c92 ("slub: slub-specific propagation changes")
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Glauber Costa <glauber@scylladb.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200429222356.4322-1-cai@lca.pw
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 52f2347808 ]
The slub_debug is able to fix the corrupted slab freelist/page.
However, alloc_debug_processing() only checks the validity of current
and next freepointer during allocation path. As a result, once some
objects have their freepointers corrupted, deactivate_slab() may lead to
page fault.
Below is from a test kernel module when 'slub_debug=PUF,kmalloc-128
slub_nomerge'. The test kernel corrupts the freepointer of one free
object on purpose. Unfortunately, deactivate_slab() does not detect it
when iterating the freechain.
BUG: unable to handle page fault for address: 00000000123456f8
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
... ...
RIP: 0010:deactivate_slab.isra.92+0xed/0x490
... ...
Call Trace:
___slab_alloc+0x536/0x570
__slab_alloc+0x17/0x30
__kmalloc+0x1d9/0x200
ext4_htree_store_dirent+0x30/0xf0
htree_dirblock_to_tree+0xcb/0x1c0
ext4_htree_fill_tree+0x1bc/0x2d0
ext4_readdir+0x54f/0x920
iterate_dir+0x88/0x190
__x64_sys_getdents+0xa6/0x140
do_syscall_64+0x49/0x170
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Therefore, this patch adds extra consistency check in deactivate_slab().
Once an object's freepointer is corrupted, all following objects
starting at this object are isolated.
[akpm@linux-foundation.org: fix build with CONFIG_SLAB_DEBUG=n]
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joe Jin <joe.jin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200331031450.12182-1-dongli.zhang@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Laurent Dufour