path: root/include/linux/psi_types.h
diff options
authorSuren Baghdasaryan <surenb@google.com>2022-01-11 15:23:09 -0800
committerPeter Zijlstra <peterz@infradead.org>2022-01-18 12:09:57 +0100
commita06247c6804f1a7c86a2e5398a4c1f1db1471848 (patch)
tree671ed11c7238f3c0d0a13413949ae41356fcc5af /include/linux/psi_types.h
parentMerge tag 'mailbox-v5.17' of git://git.linaro.org/landing-teams/working/fujitsu/integration (diff)
psi: Fix uaf issue when psi trigger is destroyed while being polled
With write operation on psi files replacing old trigger with a new one, the lifetime of its waitqueue is totally arbitrary. Overwriting an existing trigger causes its waitqueue to be freed and pending poll() will stumble on trigger->event_wait which was destroyed. Fix this by disallowing to redefine an existing psi trigger. If a write operation is used on a file descriptor with an already existing psi trigger, the operation will fail with EBUSY error. Also bypass a check for psi_disabled in the psi_trigger_destroy as the flag can be flipped after the trigger is created, leading to a memory leak. Fixes: 0e94682b73bf ("psi: introduce psi monitor") Reported-by: syzbot+cdb5dd11c97cc532efad@syzkaller.appspotmail.com Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Analyzed-by: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Eric Biggers <ebiggers@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220111232309.1786347-1-surenb@google.com
Diffstat (limited to '')
1 files changed, 0 insertions, 3 deletions
diff --git a/include/linux/psi_types.h b/include/linux/psi_types.h
index 516c0fe836fd..1a3cef26d129 100644
--- a/include/linux/psi_types.h
+++ b/include/linux/psi_types.h
@@ -141,9 +141,6 @@ struct psi_trigger {
* events to one per window
u64 last_event_time;
- /* Refcounting to prevent premature destruction */
- struct kref refcount;
struct psi_group {