Commit 34343786 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: unpark SQPOLL thread for cancelation 



We park SQPOLL task before going into io_uring_cancel_files(), so the
task won't run task_works including those that might be important for
the cancellation passes. In this case it's io_poll_remove_one(), which
frees requests via io_put_req_deferred().

Unpark it for while waiting, it's ok as we disable submissions
beforehand, so no new requests will be generated.

INFO: task syz-executor893:8493 blocked for more than 143 seconds.
Call Trace:
 context_switch kernel/sched/core.c:4327 [inline]
 __schedule+0x90c/0x21a0 kernel/sched/core.c:5078
 schedule+0xcf/0x270 kernel/sched/core.c:5157
 io_uring_cancel_files fs/io_uring.c:8912 [inline]
 io_uring_cancel_task_requests+0xe70/0x11a0 fs/io_uring.c:8979
 __io_uring_files_cancel+0x110/0x1b0 fs/io_uring.c:9067
 io_uring_files_cancel include/linux/io_uring.h:51 [inline]
 do_exit+0x2fe/0x2ae0 kernel/exit.c:780
 do_group_exit+0x125/0x310 kernel/exit.c:922
 __do_sys_exit_group kernel/exit.c:933 [inline]
 __se_sys_exit_group kernel/exit.c:931 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Cc: stable@vger.kernel.org # 5.5+
Reported-by: default avatar <syzbot+695b03d82fa8e4901b06@syzkaller.appspotmail.com>
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 26bfa89e

fs/io_uring.c

+5 −0
Original line number Diff line number Diff line
@@ -9047,11 +9047,16 @@ static void io_uring_cancel_files(struct io_ring_ctx *ctx, 
			break;



		io_uring_try_cancel_requests(ctx, task, files);



		if (ctx->sq_data)

			io_sq_thread_unpark(ctx->sq_data);

		prepare_to_wait(&task->io_uring->wait, &wait,

				TASK_UNINTERRUPTIBLE);

		if (inflight == io_uring_count_inflight(ctx, task, files))

			schedule();

		finish_wait(&task->io_uring->wait, &wait);

		if (ctx->sq_data)

			io_sq_thread_park(ctx->sq_data);

	}

}