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From: Denis Arefev <arefev@swemel.ru>
To: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>,
	Josh Triplett <josh@joshtriplett.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	rcu@vger.kernel.org, lvc-project@linuxtesting.org,
	linux-kernel@vger.kernel.org, trufanov@swemel.ru, vfh@swemel.ru
Subject: [PATCH] srcu: The value may overflow
Date: Fri,  1 Sep 2023 12:53:41 +0300	[thread overview]
Message-ID: <20230901095341.55857-1-arefev@swemel.ru> (raw)

The value of an arithmetic expression 1 << (cpu - sdp->mynode->grplo)
is subject to overflow due to a failure to cast operands to a larger
data type before performing arithmetic

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Denis Arefev <arefev@swemel.ru>
---
 kernel/rcu/srcutree.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index 20d7a238d675..e14b74fb1ba0 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -223,7 +223,7 @@ static bool init_srcu_struct_nodes(struct srcu_struct *ssp, gfp_t gfp_flags)
 				snp->grplo = cpu;
 			snp->grphi = cpu;
 		}
-		sdp->grpmask = 1 << (cpu - sdp->mynode->grplo);
+		sdp->grpmask = 1UL << (cpu - sdp->mynode->grplo);
 	}
 	smp_store_release(&ssp->srcu_sup->srcu_size_state, SRCU_SIZE_WAIT_BARRIER);
 	return true;
-- 
2.25.1


             reply	other threads:[~2023-09-01  9:59 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-01  9:53 Denis Arefev [this message]
2023-09-01 13:31 ` [PATCH] srcu: The value may overflow Mathieu Desnoyers
2023-09-02 14:17   ` Mathieu Desnoyers

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