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Manfred Spraul c626bc46ed ipc/sem.c: fix incorrect sem_lock pairing
Based on the syzcaller test case from dvyukov:

  08d0a261fe/gistfile1.txt

The slow (i.e.: failure to acquire) syscall exit from semtimedop()
incorrectly assumed that the the same lock is acquired as it was at the
initial syscall entry.

This is wrong:
 - thread A: single semop semop(), sleeps
 - thread B: multi semop semop(), sleeps
 - thread A: woken up by signal/timeout

With this sequence, the initial sem_lock() call locks the per-semaphore
spinlock, and it is unlocked with sem_unlock().  The call at the syscall
return locks the global spinlock.  Because locknum is not updated, the
following sem_unlock() call unlocks the per-semaphore spinlock, which is
actually not locked.

The fix is trivial: Use the return value from sem_lock.

Fixes: 370b262c89 ("ipc/sem: avoid idr tree lookup for interrupted semop")
Link: http://lkml.kernel.org/r/1482215645-22328-1-git-send-email-manfred@colorfullife.com
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Reported-by: Johanna Abrahamsson <johanna@mjao.org>
Tested-by: Johanna Abrahamsson <johanna@mjao.org>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-01-10 18:31:55 -08:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-01-09 11:58:28 -08:00
block Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-01-04 09:03:37 -08:00
certs certs: Add a secondary system keyring that can be added to dynamically 2016-04-11 22:48:09 +01:00
crypto crypto: testmgr - Use heap buffer for acomp test input 2016-12-27 17:32:11 +08:00
Documentation VFIO fixes for v4.10-rc3 2017-01-06 11:19:03 -08:00
drivers amdgpu, radeon, msm, meson, tilcdc, drm fixes. 2017-01-09 12:54:20 -08:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs ocfs2: fix crash caused by stale lvb with fsdlm plugin 2017-01-10 18:31:54 -08:00
include mm: get rid of __GFP_OTHER_NODE 2017-01-10 18:31:55 -08:00
init mm: add PageWaiters indicating tasks are waiting for a page bit 2016-12-25 11:54:48 -08:00
ipc ipc/sem.c: fix incorrect sem_lock pairing 2017-01-10 18:31:55 -08:00
kernel mm: fix devm_memremap_pages crash, use mem_hotplug_{begin, done} 2017-01-10 18:31:54 -08:00
lib lib/Kconfig.debug: fix frv build failure 2017-01-10 18:31:55 -08:00
mm mm: get rid of __GFP_OTHER_NODE 2017-01-10 18:31:55 -08:00
net netlabel: add CALIPSO to the list of built-in protocols 2017-01-06 22:20:45 -05:00
samples vfio-mdev: fix some error codes in the sample code 2017-01-04 08:32:23 -07:00
scripts gcc-plugins: update gcc-common.h for gcc-7 2017-01-03 12:08:59 -08:00
security Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
sound Revert "ALSA: firewire-lib: change structure member with proper type" 2017-01-05 08:39:47 +01:00
tools mm: get rid of __GFP_OTHER_NODE 2017-01-10 18:31:55 -08:00
usr kbuild: initramfs cleanup, set target from Kconfig 2017-01-05 09:40:16 -08:00
virt Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-25 14:30:04 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.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 Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2016-10-15 09:26:12 -07:00
COPYING
CREDITS CREDITS: Remove outdated address information 2016-12-21 15:21:29 -08:00
Kbuild scripts/gdb: provide linux constants 2016-05-23 17:04:14 -07:00
Kconfig
MAINTAINERS MAINTAINERS: remove duplicate bug filling description 2017-01-10 18:31:54 -08:00
Makefile Linux 4.10-rc3 2017-01-08 14:18:17 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

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.