From: Kuniyuki Iwashima kuniyu@amazon.com
[ Upstream commit f613d86d014b6375a4085901de39406598121e35 ]
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_minmax() to use READ_ONCE() and WRITE_ONCE() internally to fix data-races on the sysctl side. For now, proc_dointvec_minmax() itself is tolerant to a data-race, but we still need to add annotations on the other subsystem's side.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima kuniyu@amazon.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/sysctl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index b152e0a30a2b..f5134435fb9c 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -988,7 +988,7 @@ static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp, if ((param->min && *param->min > tmp) || (param->max && *param->max < tmp)) return -EINVAL; - *valp = tmp; + WRITE_ONCE(*valp, tmp); }
return 0;