From: Kuniyuki Iwashima kuniyu@amazon.com
[ Upstream commit 2d3b559df3ed39258737789aae2ae7973d205bc1 ]
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_douintvec_minmax() to use READ_ONCE() and WRITE_ONCE() internally to fix data-races on the sysctl side. For now, proc_douintvec_minmax() itself is tolerant to a data-race, but we still need to add annotations on the other subsystem's side.
Fixes: 61d9b56a8920 ("sysctl: add unsigned int range support") 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 22ebf3f5eefe..a769f64a78ed 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -995,7 +995,7 @@ static int do_proc_douintvec_minmax_conv(unsigned long *lvalp, (param->max && *param->max < tmp)) return -ERANGE;
- *valp = tmp; + WRITE_ONCE(*valp, tmp); }
return 0;