]> git.hungrycats.org Git - linux/commit
io_uring: fix possible deadlock in io_register_iowq_max_workers()
authorHagar Hemdan <hagarhem@amazon.com>
Tue, 4 Jun 2024 13:05:27 +0000 (13:05 +0000)
committerJens Axboe <axboe@kernel.dk>
Tue, 4 Jun 2024 13:39:17 +0000 (07:39 -0600)
commit73254a297c2dd094abec7c9efee32455ae875bdf
treecc04d94e87d77ad05f00a22e03697fcf9520e7a3
parent91215f70ea8541e9011c0b48f8b59b9e0ce6953b
io_uring: fix possible deadlock in io_register_iowq_max_workers()

The io_register_iowq_max_workers() function calls io_put_sq_data(),
which acquires the sqd->lock without releasing the uring_lock.
Similar to the commit 009ad9f0c6ee ("io_uring: drop ctx->uring_lock
before acquiring sqd->lock"), this can lead to a potential deadlock
situation.

To resolve this issue, the uring_lock is released before calling
io_put_sq_data(), and then it is re-acquired after the function call.

This change ensures that the locks are acquired in the correct
order, preventing the possibility of a deadlock.

Suggested-by: Maximilian Heyne <mheyne@amazon.de>
Signed-off-by: Hagar Hemdan <hagarhem@amazon.com>
Link: https://lore.kernel.org/r/20240604130527.3597-1-hagarhem@amazon.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_uring/register.c