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Jason Gunthorpe 9137108cc3 RDMA/rdma_cm: Fix use after free race with process_one_req
process_one_req() can race with rdma_addr_cancel():

           CPU0                                 CPU1
           ====                                 ====
 process_one_work()
  debug_work_deactivate(work);
  process_one_req()
                                        rdma_addr_cancel()
	                                  mutex_lock(&lock);
 			    	           set_timeout(&req->work,..);
                                              __queue_work()
				   	       debug_work_activate(work);
	                                  mutex_unlock(&lock);

   mutex_lock(&lock);
[..]
	list_del(&req->list);
   mutex_unlock(&lock);
[..]

   // ODEBUG explodes since the work is still queued.
   kfree(req);

Causing ODEBUG to detect the use after free:

ODEBUG: free active (active state 0) object type: work_struct hint: process_one_req+0x0/0x6c0 include/net/dst.h:165
WARNING: CPU: 0 PID: 79 at lib/debugobjects.c:291 debug_print_object+0x166/0x220 lib/debugobjects.c:288
kvm: emulating exchange as write
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 79 Comm: kworker/u4:3 Not tainted 4.16.0-rc6+ #361
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: ib_addr process_one_req
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x24d lib/dump_stack.c:53
 panic+0x1e4/0x41c kernel/panic.c:183
 __warn+0x1dc/0x200 kernel/panic.c:547
 report_bug+0x1f4/0x2b0 lib/bug.c:186
 fixup_bug.part.11+0x37/0x80 arch/x86/kernel/traps.c:178
 fixup_bug arch/x86/kernel/traps.c:247 [inline]
 do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:986
RIP: 0010:debug_print_object+0x166/0x220 lib/debugobjects.c:288
RSP: 0000:ffff8801d966f210 EFLAGS: 00010086
RAX: dffffc0000000008 RBX: 0000000000000003 RCX: ffffffff815acd6e
RDX: 0000000000000000 RSI: 1ffff1003b2cddf2 RDI: 0000000000000000
RBP: ffff8801d966f250 R08: 0000000000000000 R09: 1ffff1003b2cddc8
R10: ffffed003b2cde71 R11: ffffffff86f39a98 R12: 0000000000000001
R13: ffffffff86f15540 R14: ffffffff86408700 R15: ffffffff8147c0a0
 __debug_check_no_obj_freed lib/debugobjects.c:745 [inline]
 debug_check_no_obj_freed+0x662/0xf1f lib/debugobjects.c:774
 kfree+0xc7/0x260 mm/slab.c:3799
 process_one_req+0x2e7/0x6c0 drivers/infiniband/core/addr.c:592
 process_one_work+0xc47/0x1bb0 kernel/workqueue.c:2113
 worker_thread+0x223/0x1990 kernel/workqueue.c:2247
 kthread+0x33c/0x400 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406

Fixes: 5fff41e1f8 ("IB/core: Fix race condition in resolving IP to MAC")
Reported-by: <syzbot+3b4acab09b6463472d0a@syzkaller.appspotmail.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2018-03-27 13:19:01 -06:00
arch unify {de,}mangle_poll(), get rid of kernel-side POLL... 2018-02-11 14:37:22 -08:00
block vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
certs
crypto vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
Documentation KVM changes for 4.16 2018-02-10 13:16:35 -08:00
drivers RDMA/rdma_cm: Fix use after free race with process_one_req 2018-03-27 13:19:01 -06:00
firmware
fs vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
include RDMA/verbs: Remove restrack entry from XRCD structure 2018-03-19 14:10:30 -06:00
init membarrier: Provide core serializing command, *_SYNC_CORE 2018-02-05 21:35:03 +01:00
ipc vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
kernel vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
lib Kbuild updates for v4.16 (2nd) 2018-02-09 19:32:41 -08:00
LICENSES
mm vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
net vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
samples sample/bpf: fix erspan metadata 2018-02-06 11:32:49 -05:00
scripts Kbuild updates for v4.16 (2nd) 2018-02-09 19:32:41 -08:00
security vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
sound vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-02-09 15:34:18 -08:00
usr
virt vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS KVM changes for 4.16 2018-02-10 13:16:35 -08:00
Makefile Linux 4.16-rc1 2018-02-11 15:04:29 -08:00
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.