From: Hagar Hemdan hagarhem@amazon.com

mainline inclusion from mainline-v6.10-rc3 commit 73254a297c2dd094abec7c9efee32455ae875bdf category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAGEK8 CVE: CVE-2024-41080

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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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 Conflicts: io_uring/io_uring.c io_uring/register.c [Commit c43203154d8ac moves related functions from io_uring/io_uring.c to io_uring/register.c.] Signed-off-by: Wang Zhaolong wangzhaolong1@huawei.com --- io_uring/io_uring.c | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 5979f0fc28b2..40bd1406976c 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -4340,8 +4340,10 @@ static __cold int io_register_iowq_max_workers(struct io_ring_ctx *ctx, }

if (sqd) { + mutex_unlock(&ctx->uring_lock); mutex_unlock(&sqd->lock); io_put_sq_data(sqd); + mutex_lock(&ctx->uring_lock); }

if (copy_to_user(arg, new_count, sizeof(new_count))) @@ -4366,8 +4368,10 @@ static __cold int io_register_iowq_max_workers(struct io_ring_ctx *ctx, return 0; err: if (sqd) { + mutex_unlock(&ctx->uring_lock); mutex_unlock(&sqd->lock); io_put_sq_data(sqd); + mutex_lock(&ctx->uring_lock); } return ret; }