Commit 7d1025e5 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by David S. Miller
Browse files

sysctl: Fix data-races in proc_dointvec_ms_jiffies(). 



A sysctl variable is accessed concurrently, and there is always a chance
of data-race.  So, all readers and writers need some basic protection to
avoid load/store-tearing.

This patch changes proc_dointvec_ms_jiffies() to use READ_ONCE() and
WRITE_ONCE() internally to fix data-races on the sysctl side.  For now,
proc_dointvec_ms_jiffies() itself is tolerant to a data-race, but we still
need to add annotations on the other subsystem's side.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7dee5d77

kernel/sysctl.c

+4 −4
Original line number Diff line number Diff line
@@ -1224,9 +1224,9 @@ static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp, 


		if (jif > INT_MAX)

			return 1;

		*valp = (int)jif;

		WRITE_ONCE(*valp, (int)jif);

	} else {

		int val = *valp;

		int val = READ_ONCE(*valp);

		unsigned long lval;

		if (val < 0) {

			*negp = true;