tree 9192be9043ad4cf8d0726085d9050fb960e1c98e
parent 6c8028e3c0978f85667d9d6bbae5fe364bd43984
author Jens Axboe <axboe@kernel.dk> 1697913029 -0600
committer COS Cherry Picker <cloud-image-release@prod.google.com> 1701212702 -0800

io_uring/fdinfo: lock SQ thread while retrieving thread cpu/pid

commit 7644b1a1c9a7ae8ab99175989bfc8676055edb46 upstream.

We could race with SQ thread exit, and if we do, we'll hit a NULL pointer
dereference when the thread is cleared. Grab the SQPOLL data lock before
attempting to get the task cpu and pid for fdinfo, this ensures we have a
stable view of it.

BUG=b/309762284
TEST=presubmit
RELEASE_NOTE=Fixed CVE-2023-46862 in the Linux kernel.

cos-patch: security-moderate
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218032
Change-Id: If049ba23e65f65b628a21fb900304f41ecfac00e
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: He Gao <hegao@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/61614
Reviewed-by: Oleksandr Tymoshenko <ovt@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Main-Branch-Verified: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>