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| author |   Suren Baghdasaryan <surenb@google.com> | 2022-01-11 15:23:09 -0800 |
|---|---|---|
| committer |   Peter Zijlstra <peterz@infradead.org> | 2022-01-18 12:09:57 +0100 |
| commit | a06247c6804f1a7c86a2e5398a4c1f1db1471848 (patch) | |
| tree | 671ed11c7238f3c0d0a13413949ae41356fcc5af /include/linux/psi_types.h | |
| parent | Merge tag 'mailbox-v5.17' of git://git.linaro.org/landing-teams/working/fujitsu/integration (diff) | |
| download | linux-dev-a06247c6804f1a7c86a2e5398a4c1f1db1471848.tar.xz linux-dev-a06247c6804f1a7c86a2e5398a4c1f1db1471848.zip | |
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 '')
| -rw-r--r-- | include/linux/psi_types.h | 3 |
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 { |