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Mikulas Patocka 1eed010921 dm-delay: fix a race between delay_presuspend and delay_bio
[ Upstream commit 6fc45b6ed9 ]

In delay_presuspend, we set the atomic variable may_delay and then stop
the timer and flush pending bios. The intention here is to prevent the
delay target from re-arming the timer again.

However, this test is racy. Suppose that one thread goes to delay_bio,
sees that dc->may_delay is one and proceeds; now, another thread executes
delay_presuspend, it sets dc->may_delay to zero, deletes the timer and
flushes pending bios. Then, the first thread continues and adds the bio to
delayed->list despite the fact that dc->may_delay is false.

Fix this bug by changing may_delay's type from atomic_t to bool and
only access it while holding the delayed_bios_lock mutex. Note that we
don't have to grab the mutex in delay_resume because there are no bios
in flight at this point.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-12-03 07:31:25 +01:00
arch MIPS: KVM: Fix a build warning about variable set but not used 2023-12-03 07:31:23 +01:00
block blk-core: use pr_warn_ratelimited() in bio_check_ro() 2023-11-20 11:08:29 +01:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:22:01 +02:00
crypto crypto: pcrypt - Fix hungtask for PADATA_RESET 2023-11-28 16:56:18 +00:00
Documentation Documentation: sysctl: align cells in second content column 2023-10-25 11:58:54 +02:00
drivers dm-delay: fix a race between delay_presuspend and delay_bio 2023-12-03 07:31:25 +01:00
fs proc: sysctl: prevent aliased sysctls from getting passed to init 2023-12-03 07:31:24 +01:00
include proc: sysctl: prevent aliased sysctls from getting passed to init 2023-12-03 07:31:24 +01:00
init proc: sysctl: prevent aliased sysctls from getting passed to init 2023-12-03 07:31:24 +01:00
io_uring io_uring/fs: consider link->flags when getting path for LINKAT 2023-12-03 07:31:24 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:28:45 +01:00
kernel lockdep: Fix block chain corruption 2023-12-03 07:31:23 +01:00
lib lib/Kconfig.debug: do not enable DEBUG_PREEMPT by default 2023-10-25 11:58:54 +02:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm mm: kmem: drop __GFP_NOFAIL when allocating objcg vectors 2023-11-28 16:56:35 +00:00
net net/smc: avoid data corruption caused by decline 2023-12-03 07:31:22 +01:00
samples samples/hw_breakpoint: fix building without module unloading 2023-09-23 11:10:01 +02:00
scripts randstruct: Fix gcc-plugin performance mode to stay in group 2023-11-28 16:56:26 +00:00
security KEYS: trusted: Rollback init_trusted() consistently 2023-11-28 16:56:30 +00:00
sound ALSA: hda/realtek - Enable internal speaker of ASUS K6500ZC 2023-11-28 16:56:32 +00:00
tools selftests/resctrl: Reduce failures due to outliers in MBA/MBM tests 2023-11-28 16:56:30 +00:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: Grab a reference to KVM for VM and vCPU stats file descriptors 2023-08-03 10:22:40 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-26 14:23:27 +02:00
Makefile Linux 5.15.140 2023-11-28 16:56:37 +00:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

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.