| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.10 045/112] sysctl: Fix data races in proc_douintvec_minmax(). | Date | Tue, 19 Jul 2022 13:53:38 +0200 |
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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 1800907da60c..df6090ba1d0b 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1025,7 +1025,7 @@ 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; -- 2.35.1
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