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Nikolay Borisov 6d7225f0cc lockdep: teach lockdep about memalloc_noio_save 
Patch series "scope GFP_NOFS api", v5.

This patch (of 7):

Commit 21caf2fc19 ("mm: teach mm by current context info to not do I/O
during memory allocation") added the memalloc_noio_(save|restore)
functions to enable people to modify the MM behavior by disabling I/O
during memory allocation.

This was further extended in commit 934f3072c1 ("mm: clear __GFP_FS
when PF_MEMALLOC_NOIO is set").

memalloc_noio_* functions prevent allocation paths recursing back into
the filesystem without explicitly changing the flags for every
allocation site.

However, lockdep hasn't been keeping up with the changes and it entirely
misses handling the memalloc_noio adjustments.  Instead, it is left to
the callers of __lockdep_trace_alloc to call the function after they
have shaven the respective GFP flags which can lead to false positives:

  =================================
   [ INFO: inconsistent lock state ]
   4.10.0-nbor #134 Not tainted
   ---------------------------------
   inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage.
   fsstress/3365 [HC0[0]:SC0[0]:HE1:SE1] takes:
    (&xfs_nondir_ilock_class){++++?.}, at: xfs_ilock+0x141/0x230
   {IN-RECLAIM_FS-W} state was registered at:
     __lock_acquire+0x62a/0x17c0
     lock_acquire+0xc5/0x220
     down_write_nested+0x4f/0x90
     xfs_ilock+0x141/0x230
     xfs_reclaim_inode+0x12a/0x320
     xfs_reclaim_inodes_ag+0x2c8/0x4e0
     xfs_reclaim_inodes_nr+0x33/0x40
     xfs_fs_free_cached_objects+0x19/0x20
     super_cache_scan+0x191/0x1a0
     shrink_slab+0x26f/0x5f0
     shrink_node+0xf9/0x2f0
     kswapd+0x356/0x920
     kthread+0x10c/0x140
     ret_from_fork+0x31/0x40
   irq event stamp: 173777
   hardirqs last  enabled at (173777): __local_bh_enable_ip+0x70/0xc0
   hardirqs last disabled at (173775): __local_bh_enable_ip+0x37/0xc0
   softirqs last  enabled at (173776): _xfs_buf_find+0x67a/0xb70
   softirqs last disabled at (173774): _xfs_buf_find+0x5db/0xb70

   other info that might help us debug this:
    Possible unsafe locking scenario:

          CPU0
          ----
     lock(&xfs_nondir_ilock_class);
     <Interrupt>
       lock(&xfs_nondir_ilock_class);

    *** DEADLOCK ***

   4 locks held by fsstress/3365:
    #0:  (sb_writers#10){++++++}, at: mnt_want_write+0x24/0x50
    #1:  (&sb->s_type->i_mutex_key#12){++++++}, at: vfs_setxattr+0x6f/0xb0
    #2:  (sb_internal#2){++++++}, at: xfs_trans_alloc+0xfc/0x140
    #3:  (&xfs_nondir_ilock_class){++++?.}, at: xfs_ilock+0x141/0x230

   stack backtrace:
   CPU: 0 PID: 3365 Comm: fsstress Not tainted 4.10.0-nbor #134
   Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
   Call Trace:
    kmem_cache_alloc_node_trace+0x3a/0x2c0
    vm_map_ram+0x2a1/0x510
    _xfs_buf_map_pages+0x77/0x140
    xfs_buf_get_map+0x185/0x2a0
    xfs_attr_rmtval_set+0x233/0x430
    xfs_attr_leaf_addname+0x2d2/0x500
    xfs_attr_set+0x214/0x420
    xfs_xattr_set+0x59/0xb0
    __vfs_setxattr+0x76/0xa0
    __vfs_setxattr_noperm+0x5e/0xf0
    vfs_setxattr+0xae/0xb0
    setxattr+0x15e/0x1a0
    path_setxattr+0x8f/0xc0
    SyS_lsetxattr+0x11/0x20
    entry_SYSCALL_64_fastpath+0x23/0xc6

Let's fix this by making lockdep explicitly do the shaving of respective
GFP flags.

Fixes: 934f3072c1 ("mm: clear __GFP_FS when PF_MEMALLOC_NOIO is set")
Link: http://lkml.kernel.org/r/20170306131408.9828-2-mhocko@kernel.org
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Chris Mason <clm@fb.com>
Cc: David Sterba <dsterba@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 		2017-05-03 15:52:09 -07:00
Documentation mm: memcontrol: provide shmem statistics 2017-05-03 15:52:08 -07:00
arch blackfin: bf609: let clk_disable() return immediately if clk is NULL 2017-05-03 15:52:07 -07:00
block A reasonably busy cycle for documentation this time around. There is a new 2017-05-02 10:21:17 -07:00
certs KEYS: Use structure to capture key restriction function and data 2017-04-04 14:10:10 -07:00
crypto Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2017-05-03 08:50:52 -07:00
drivers Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2017-05-03 08:50:52 -07:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs proc: show MADV_FREE pages info in smaps 2017-05-03 15:52:08 -07:00
include mm: use is_migrate_highatomic() to simplify the code 2017-05-03 15:52:08 -07:00
init Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2017-05-02 19:09:35 -07:00
ipc kernel-api.rst: fix a series of errors when parsing C files 2017-04-02 14:31:49 -06:00
kernel lockdep: teach lockdep about memalloc_noio_save 2017-05-03 15:52:09 -07:00
lib lib/dma-debug.c: make locking work for RT 2017-05-03 15:52:07 -07:00
mm mm, vmstat: suppress pcp stats for unpopulated zones in zoneinfo 2017-05-03 15:52:08 -07:00
net Merge branch 'stable-4.12' of git://git.infradead.org/users/pcmoore/audit 2017-05-03 09:21:59 -07:00
samples Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching 2017-05-02 18:24:16 -07:00
scripts scripts/spelling.txt: add several more common spelling mistakes 2017-05-03 15:52:07 -07:00
security Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2017-05-03 08:50:52 -07:00
sound LED updates for 4.12 2017-05-01 13:12:49 -07:00
tools Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2017-05-02 19:09:35 -07:00
usr kbuild: initramfs cleanup, set target from Kconfig 2017-01-05 09:40:16 -08:00
virt KVM/ARM Fixes for v4.11-rc6 2017-04-05 16:27:47 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-08-02 16:48:52 -04:00
.mailmap mailmap: add Martin Kepplinger's email 2017-04-13 18:24:21 -07:00
COPYING [PATCH] update FSF address in COPYING 2005-09-10 10:06:29 -07:00
CREDITS avr32: remove support for AVR32 architecture 2017-05-01 09:27:15 +02:00
Kbuild scripts/gdb: provide linux constants 2016-05-23 17:04:14 -07:00
Kconfig kbuild: migrate all arch to the kconfig mainmenu upgrade 2010-09-19 22:54:11 -04:00
MAINTAINERS Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2017-05-02 19:09:35 -07:00
Makefile A reasonably busy cycle for documentation this time around. There is a new 2017-05-02 10:21:17 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README 

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.