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Subject[PATCH v2 net 04/12] sysctl: Fix data races in proc_douintvec_minmax().
Date
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>
---
kernel/sysctl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 4d87832367f2..379721a03d41 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -923,7 +923,7 @@ 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;
--
2.30.2
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