Re: [PATCH 14/15] kernel: convert futex_pi_state.refcount from atomic_t to refcount_t

From
Peter Zijlstra <peterz@infradead.org>
Date
2017-07-07 09:26:21
Also in
linux-fsdevel, lkml
Reply to
Elena Reshetova, 2017-07-07
On Fri, Jul 07, 2017 at 12:04:28PM +0300, Elena Reshetova wrote:
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <redacted>
Signed-off-by: Kees Cook <redacted>
Signed-off-by: David Windsor <redacted>
I'll let tglx comment on the SoB chain, I know he likes those :-) You
did Cc him right, seeing how he's the maintainer of this stuff..

*sigh* you didn't :-( After so many patches send you _really_ should
know to Cc the right people.
quoted hunk ↗ jump to hunk
---
 kernel/futex.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)
quoted hunk ↗ jump to hunk
@@ -814,7 +815,7 @@ static struct futex_pi_state *alloc_pi_state(void)
 
 static void get_pi_state(struct futex_pi_state *pi_state)
 {
-	WARN_ON_ONCE(!atomic_inc_not_zero(&pi_state->refcount));
+	WARN_ON_ONCE(!refcount_inc_not_zero(&pi_state->refcount));
 }
I think we have refcount_inc() for just that case, no?

Thread (27 messages) 27 messages, 5 authors, last reply 2017-07-07
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