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Pavel Begunkov bc79ff0b1a io_uring: fix wqe->lock/completion_lock deadlock
commit 907d1df30a upstream.

Joseph reports following deadlock:

CPU0:
...
io_kill_linked_timeout  // &ctx->completion_lock
io_commit_cqring
__io_queue_deferred
__io_queue_async_work
io_wq_enqueue
io_wqe_enqueue  // &wqe->lock

CPU1:
...
__io_uring_files_cancel
io_wq_cancel_cb
io_wqe_cancel_pending_work  // &wqe->lock
io_cancel_task_cb  // &ctx->completion_lock

Only __io_queue_deferred() calls queue_async_work() while holding
ctx->completion_lock, enqueue drained requests via io_req_task_queue()
instead.

Cc: stable@vger.kernel.org # 5.9+
Reported-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-02-03 23:28:41 +01:00
arch KVM: x86: get smi pending status correctly 2021-02-03 23:28:41 +01:00
block blk-mq-debugfs: Add decode for BLK_MQ_F_TAG_HCTX_SHARED 2021-01-19 18:27:29 +01:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto crypto: xor - Fix divide error in do_xor_speed() 2021-01-27 11:54:52 +01:00
Documentation KVM: Forbid the use of tagged userspace addresses for memslots 2021-02-03 23:28:41 +01:00
drivers drivers: soc: atmel: add null entry at the end of at91_soc_allowed_list[] 2021-02-03 23:28:40 +01:00
fs io_uring: fix wqe->lock/completion_lock deadlock 2021-02-03 23:28:41 +01:00
include x86/entry: Emit a symbol for register restoring thunk 2021-02-03 23:28:40 +01:00
init rcu-tasks: Move RCU-tasks initialization to before early_initcall() 2021-01-19 18:27:28 +01:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel PM: hibernate: flush swap writer after marking 2021-02-03 23:28:40 +01:00
lib iov_iter: fix the uaccess area in copy_compat_iovec_from_user 2021-01-27 11:55:09 +01:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm mm: fix a race on nr_swap_pages 2021-01-30 13:55:19 +01:00
net wext: fix NULL-ptr-dereference with cfg80211's lack of commit() 2021-02-03 23:28:38 +01:00
samples samples/bpf: Fix possible hang in xdpsock with multiple threads 2020-12-30 11:53:49 +01:00
scripts Revert "kconfig: remove 'kvmconfig' and 'xenconfig' shorthands" 2021-01-23 16:03:57 +01:00
security dump_common_audit_data(): fix racy accesses to ->d_name 2021-01-19 18:27:29 +01:00
sound ASoC: AMD Renoir - refine DMI entries for some Lenovo products 2021-02-03 23:28:38 +01:00
tools tools: Factor HOSTCC, HOSTLD, HOSTAR definitions 2021-01-30 13:55:19 +01:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: Forbid the use of tagged userspace addresses for memslots 2021-02-03 23:28:41 +01:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.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: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
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 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-12-10 15:30:13 -08:00
Makefile Linux 5.10.12 2021-01-30 13:55:20 +01:00
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.