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| author |   Jens Axboe <axboe@kernel.dk> | 2021-03-29 06:52:44 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-03-30 14:36:46 -0600 |
| commit | 82734c5b1b24c020d701cf90ccb075e43a5ccb07 (patch) | |
| tree | 582d2b194fefa60fd97b52e0b7cd2b7010610ebf /fs/io_uring.c | |
| parent | io_uring: handle setup-failed ctx in kill_timeouts (diff) | |
| download | linux-dev-82734c5b1b24c020d701cf90ccb075e43a5ccb07.tar.xz linux-dev-82734c5b1b24c020d701cf90ccb075e43a5ccb07.zip | |
io_uring: drop sqd lock before handling signals for SQPOLL
Don't call into get_signal() with the sqd mutex held, it'll fail if we're
freezing the task and we'll get complaints on locks still being held:
====================================
WARNING: iou-sqp-8386/8387 still has locks held!
5.12.0-rc4-syzkaller #0 Not tainted
------------------------------------
1 lock held by iou-sqp-8386/8387:
#0: ffff88801e1d2470 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread+0x24c/0x13a0 fs/io_uring.c:6731
stack backtrace:
CPU: 1 PID: 8387 Comm: iou-sqp-8386 Not tainted 5.12.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x141/0x1d7 lib/dump_stack.c:120
try_to_freeze include/linux/freezer.h:66 [inline]
get_signal+0x171a/0x2150 kernel/signal.c:2576
io_sq_thread+0x8d2/0x13a0 fs/io_uring.c:6748
Fold the get_signal() case in with the parking checks, as we need to drop
the lock in both cases, and since we need to be checking for parking when
juggling the lock anyway.
Reported-by: syzbot+796d767eb376810256f5@syzkaller.appspotmail.com
Fixes: dbe1bdbb39db ("io_uring: handle signals for IO threads like a normal thread")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to '')
| -rw-r--r-- | fs/io_uring.c | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 088a9d3c420a..6d7a1b69712b 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -6733,22 +6733,25 @@ static int io_sq_thread(void *data) int ret; bool cap_entries, sqt_spin, needs_sched; - if (test_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state)) { + if (test_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state) || + signal_pending(current)) { + bool did_sig = false; + mutex_unlock(&sqd->lock); + if (signal_pending(current)) { + struct ksignal ksig; + + did_sig = get_signal(&ksig); + } cond_resched(); mutex_lock(&sqd->lock); + if (did_sig) + break; io_run_task_work(); io_run_task_work_head(&sqd->park_task_work); timeout = jiffies + sqd->sq_thread_idle; continue; } - if (signal_pending(current)) { - struct ksignal ksig; - - if (!get_signal(&ksig)) - continue; - break; - } sqt_spin = false; cap_entries = !list_is_singular(&sqd->ctx_list); list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) { |