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  1. 19 10月, 2021 16 次提交
  3. 18 10月, 2021 3 次提交
  5. 14 10月, 2021 1 次提交
  7. 02 10月, 2021 1 次提交
  9. 25 9月, 2021 8 次提交
  11. 15 9月, 2021 3 次提交
  13. 14 9月, 2021 3 次提交
  15. 13 9月, 2021 1 次提交
  17. 10 9月, 2021 1 次提交
  19. 09 9月, 2021 3 次提交
    • P
      io_uring: fail links of cancelled timeouts · 2ae2eb9d
      由 Pavel Begunkov 提交于 
      When we cancel a timeout we should mark it with REQ_F_FAIL, so
linked requests are cancelled as well, but not queued for further
execution.

Cc: stable@vger.kernel.org
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/fff625b44eeced3a5cae79f60e6acf3fbdf8f990.1631192135.git.asml.silence@gmail.comSigned-off-by: NJens Axboe <axboe@kernel.dk>
      2ae2eb9d
    • J
      io_uring: drop ctx->uring_lock before acquiring sqd->lock · 009ad9f0
      由 Jens Axboe 提交于 
      The SQPOLL thread dictates the lock order, and we hold the ctx->uring_lock
for all the registration opcodes. We also hold a ref to the ctx, and we
do drop the lock for other reasons to quiesce, so it's fine to drop the
ctx lock temporarily to grab the sqd->lock. This fixes the following
lockdep splat:

======================================================
WARNING: possible circular locking dependency detected
5.14.0-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.5/25433 is trying to acquire lock:
ffff888023426870 (&sqd->lock){+.+.}-{3:3}, at: io_register_iowq_max_workers fs/io_uring.c:10551 [inline]
ffff888023426870 (&sqd->lock){+.+.}-{3:3}, at: __io_uring_register fs/io_uring.c:10757 [inline]
ffff888023426870 (&sqd->lock){+.+.}-{3:3}, at: __do_sys_io_uring_register+0x10aa/0x2e70 fs/io_uring.c:10792

but task is already holding lock:
ffff8880885b40a8 (&ctx->uring_lock){+.+.}-{3:3}, at: __do_sys_io_uring_register+0x2e1/0x2e70 fs/io_uring.c:10791

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&ctx->uring_lock){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:596 [inline]
       __mutex_lock+0x131/0x12f0 kernel/locking/mutex.c:729
       __io_sq_thread fs/io_uring.c:7291 [inline]
       io_sq_thread+0x65a/0x1370 fs/io_uring.c:7368
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

-> #0 (&sqd->lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3051 [inline]
       check_prevs_add kernel/locking/lockdep.c:3174 [inline]
       validate_chain kernel/locking/lockdep.c:3789 [inline]
       __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015
       lock_acquire kernel/locking/lockdep.c:5625 [inline]
       lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590
       __mutex_lock_common kernel/locking/mutex.c:596 [inline]
       __mutex_lock+0x131/0x12f0 kernel/locking/mutex.c:729
       io_register_iowq_max_workers fs/io_uring.c:10551 [inline]
       __io_uring_register fs/io_uring.c:10757 [inline]
       __do_sys_io_uring_register+0x10aa/0x2e70 fs/io_uring.c:10792
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x44/0xae

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ctx->uring_lock);
                               lock(&sqd->lock);
                               lock(&ctx->uring_lock);
  lock(&sqd->lock);

 *** DEADLOCK ***

Fixes: 2e480058 ("io-wq: provide a way to limit max number of workers")
Reported-by: syzbot+97fa56483f69d677969f@syzkaller.appspotmail.com
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      009ad9f0
    • P
      io_uring: fix missing mb() before waitqueue_active · c57a91fb
      由 Pavel Begunkov 提交于 
      In case of !SQPOLL, io_cqring_ev_posted_iopoll() doesn't provide a
memory barrier required by waitqueue_active(&ctx->poll_wait). There is
a wq_has_sleeper(), which does smb_mb() inside, but it's called only for
SQPOLL.

Fixes: 5fd46178 ("io_uring: be smarter about waking multiple CQ ring waiters")
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/2982e53bcea2274006ed435ee2a77197107d8a29.1631130542.git.asml.silence@gmail.comSigned-off-by: NJens Axboe <axboe@kernel.dk>
      c57a91fb