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From: Colin King <colin.king@canonical.com>
To: Andrew Morton <akpm@linux-foundation.org>,
	Davidlohr Bueso <dave@stgolabs.net>,
	Manfred Spraul <manfred@colorfullife.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>, Nikolay Borisov <kernel@kyup.com>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] ipc/sem: ensure we left shift a ULL rather than a 32 bit integer
Date: Fri, 28 Oct 2016 19:11:29 +0100	[thread overview]
Message-ID: <20161028181129.7311-1-colin.king@canonical.com> (raw)

From: Colin Ian King <colin.king@canonical.com>

The left shift amount is sop->sem_num % 64, which is up to 63, so
ensure we are shifting a ULL rather than a 32 bit value.

CoverityScan CID#1372862 "Bad bit shift operation"

Fixes: 7c24530cb4e3c0ae ("ipc/sem: optimize perform_atomic_semop()")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 ipc/sem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ipc/sem.c b/ipc/sem.c
index ebd18a7..ca4aa23 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -1839,7 +1839,7 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
 
 	max = 0;
 	for (sop = sops; sop < sops + nsops; sop++) {
-		unsigned long mask = 1 << ((sop->sem_num) % BITS_PER_LONG);
+		unsigned long mask = 1ULL << ((sop->sem_num) % BITS_PER_LONG);
 
 		if (sop->sem_num >= max)
 			max = sop->sem_num;
-- 
2.9.3

             reply	other threads:[~2016-10-28 18:11 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-28 18:11 Colin King [this message]
2016-10-28 19:21 ` Manfred Spraul
2016-10-28 19:29   ` Colin Ian King
2016-10-30 15:33     ` Manfred Spraul
2016-10-28 22:15 ` Davidlohr Bueso

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