From: Colin King <colin.king@canonical.com>
To: Boqun Feng <boqun.feng@gmail.com>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
Josh Triplett <josh@joshtriplett.org>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] rcu: shift by 1UL rather than 1 to fix sign extension error
Date: Tue, 13 Dec 2016 10:56:46 +0000 [thread overview]
Message-ID: <20161213105646.9598-1-colin.king@canonical.com> (raw)
From: Colin Ian King <colin.king@canonical.com>
mask and bit are unsigned longs, so if bit is 31 we end up sign
extending the 1 and mask ends up as 0xffffffff80000000. Fix this
by explicitly adding integer suffix UL ensure 1 is a unsigned long
rather than an signed int.
Issue found with static analysis with CoverityScan, CID 1388564
Fixes: 8965c3ce4718754db ("rcu: Use leaf_node_for_each_mask_possible_cpu() in force_qs_rnp()")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
kernel/rcu/tree.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 10162ac..6ecedd8 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3051,7 +3051,7 @@ static void force_qs_rnp(struct rcu_state *rsp,
leaf_node_for_each_mask_possible_cpu(rnp, rnp->qsmask, bit, cpu)
if (f(per_cpu_ptr(rsp->rda, cpu), isidle, maxj))
- mask |= 1 << bit;
+ mask |= 1UL << bit;
if (mask != 0) {
/* Idle/offline CPUs, report (releases rnp->lock. */
--
2.10.2
next reply other threads:[~2016-12-13 10:57 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-13 10:56 Colin King [this message]
2016-12-13 11:21 ` [PATCH] rcu: shift by 1UL rather than 1 to fix sign extension error Boqun Feng
2016-12-13 11:33 ` Colin Ian King
2016-12-13 15:00 ` Paul E. McKenney
2016-12-14 14:42 ` Boqun Feng
2016-12-14 14:54 ` Colin Ian King
2016-12-13 12:25 ` Boqun Feng
2016-12-13 15:05 ` Paul E. McKenney
2016-12-13 17:16 ` Mark Rutland
[not found] ` <CAL0jBu8ackxPrOALVnx96FSyD_-sZAAMySikqYw2uf8LEezr9g@mail.gmail.com>
2016-12-13 18:36 ` Paul E. McKenney
2016-12-14 0:47 ` Boqun Feng
2016-12-14 1:40 ` Boqun Feng
2016-12-14 4:13 ` Paul E. McKenney
2016-12-14 10:55 ` Mark Rutland
2016-12-14 13:03 ` Boqun Feng
2016-12-14 1:06 ` Boqun Feng
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