From: Jens Axboe axboe@kernel.dk
[ Upstream commit 23fffb2f09ce1145cbd751801d45ba74acaa6542 ]
If we have a signal pending during cancelations, it'll cause the task_work run to return an error. Since we didn't run task_work, the current task is left in TASK_INTERRUPTIBLE state when we need to re-grab the ctx mutex, and the kernel will rightfully complain about that.
Move the lock grabbing for the error cases outside the loop to avoid that issue.
Reported-by: syzbot+7df055631cd1be4586fd@syzkaller.appspotmail.com Link: https://lore.kernel.org/io-uring/0000000000003a14a905f05050b0@google.com/ Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- io_uring/cancel.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/io_uring/cancel.c b/io_uring/cancel.c index 2291a53cdabd..b4f5dfacc0c3 100644 --- a/io_uring/cancel.c +++ b/io_uring/cancel.c @@ -288,24 +288,23 @@ int io_sync_cancel(struct io_ring_ctx *ctx, void __user *arg)
ret = __io_sync_cancel(current->io_uring, &cd, sc.fd);
+ mutex_unlock(&ctx->uring_lock); if (ret != -EALREADY) break;
- mutex_unlock(&ctx->uring_lock); ret = io_run_task_work_sig(ctx); - if (ret < 0) { - mutex_lock(&ctx->uring_lock); + if (ret < 0) break; - } ret = schedule_hrtimeout(&timeout, HRTIMER_MODE_ABS); - mutex_lock(&ctx->uring_lock); if (!ret) { ret = -ETIME; break; } + mutex_lock(&ctx->uring_lock); } while (1);
finish_wait(&ctx->cq_wait, &wait); + mutex_lock(&ctx->uring_lock);
if (ret == -ENOENT || ret > 0) ret = 0;