diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2025-03-01 03:07:18 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2025-03-01 03:07:18 +0300 |
| commit | 405a41d7599be266ae6880e73252ca41770760fe (patch) | |
| tree | 1b9c7919feaedd1ad42c0e81b1bb30727a791377 /include/linux | |
| parent | 5c44ddaf7df3a06391684dde65083a092e06052b (diff) | |
| parent | b9a49520679e98700d3d89689cc91c08a1c88c1d (diff) | |
| download | linux-405a41d7599be266ae6880e73252ca41770760fe.tar.xz | |
Merge tag 'locking-urgent-2025-02-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fix from Ingo Molnar:
"Fix an rcuref_put() slowpath race"
* tag 'locking-urgent-2025-02-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
rcuref: Plug slowpath race in rcuref_put()
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/rcuref.h | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/include/linux/rcuref.h b/include/linux/rcuref.h index 2c8bfd0f1b6b..6322d8c1c6b4 100644 --- a/include/linux/rcuref.h +++ b/include/linux/rcuref.h @@ -71,27 +71,30 @@ static inline __must_check bool rcuref_get(rcuref_t *ref) return rcuref_get_slowpath(ref); } -extern __must_check bool rcuref_put_slowpath(rcuref_t *ref); +extern __must_check bool rcuref_put_slowpath(rcuref_t *ref, unsigned int cnt); /* * Internal helper. Do not invoke directly. */ static __always_inline __must_check bool __rcuref_put(rcuref_t *ref) { + int cnt; + RCU_LOCKDEP_WARN(!rcu_read_lock_held() && preemptible(), "suspicious rcuref_put_rcusafe() usage"); /* * Unconditionally decrease the reference count. The saturation and * dead zones provide enough tolerance for this. */ - if (likely(!atomic_add_negative_release(-1, &ref->refcnt))) + cnt = atomic_sub_return_release(1, &ref->refcnt); + if (likely(cnt >= 0)) return false; /* * Handle the last reference drop and cases inside the saturation * and dead zones. */ - return rcuref_put_slowpath(ref); + return rcuref_put_slowpath(ref, cnt); } /** |