From: Hagar Hemdan <hagarhem(a)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/?…
--------------------------------
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(a)amazon.de>
Signed-off-by: Hagar Hemdan <hagarhem(a)amazon.com>
Link: https://lore.kernel.org/r/20240604130527.3597-1-hagarhem@amazon.com
Signed-off-by: Jens Axboe <axboe(a)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(a)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;
}
--
2.34.3