From: Kees Cook <keescook@chromium.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
Thomas Hellstrom <thellstrom@vmware.com>,
Andi Kleen <ak@linux.intel.com>,
Daniel Micay <danielmicay@gmail.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH] kref: Avoid null pointer dereference after WARN
Date: Mon, 26 Jun 2017 20:52:15 -0700 [thread overview]
Message-ID: <20170627035215.GA132342@beast> (raw)
From: Daniel Micay <danielmicay@gmail.com>
The WARN_ON() checking for a NULL release pointer should be a BUG()
since continuing with a NULL release pointer will lead to a NULL
pointer dereference anyway.
The kref_put() case is extracted from PaX, and Kees Cook noted it should
be extended to the other two cases.
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
[kees: clarify commit log]
Signed-off-by: Kees Cook <keescook@chromium.org>
---
include/linux/kref.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/include/linux/kref.h b/include/linux/kref.h
index f4156f88f557..82a2c225eae3 100644
--- a/include/linux/kref.h
+++ b/include/linux/kref.h
@@ -66,7 +66,7 @@ static inline void kref_get(struct kref *kref)
*/
static inline int kref_put(struct kref *kref, void (*release)(struct kref *kref))
{
- WARN_ON(release == NULL);
+ BUG_ON(release == NULL);
if (refcount_dec_and_test(&kref->refcount)) {
release(kref);
@@ -79,7 +79,7 @@ static inline int kref_put_mutex(struct kref *kref,
void (*release)(struct kref *kref),
struct mutex *lock)
{
- WARN_ON(release == NULL);
+ BUG_ON(release == NULL);
if (refcount_dec_and_mutex_lock(&kref->refcount, lock)) {
release(kref);
@@ -92,7 +92,7 @@ static inline int kref_put_lock(struct kref *kref,
void (*release)(struct kref *kref),
spinlock_t *lock)
{
- WARN_ON(release == NULL);
+ BUG_ON(release == NULL);
if (refcount_dec_and_lock(&kref->refcount, lock)) {
release(kref);
--
Kees Cook
Pixel Security
next reply other threads:[~2017-06-27 3:52 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-27 3:52 Kees Cook [this message]
2017-06-27 7:06 ` [PATCH] kref: Avoid null pointer dereference after WARN Greg Kroah-Hartman
2017-06-27 11:00 ` Jason A. Donenfeld
2017-06-27 14:49 ` Andi Kleen
2017-06-27 19:11 ` Jason A. Donenfeld
2017-06-27 19:29 ` Andi Kleen
2017-06-28 11:26 ` Michal Hocko
2017-06-27 18:34 ` Kees Cook
2017-07-05 15:37 ` Peter Zijlstra
2017-06-28 11:57 ` Greg Kroah-Hartman
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