This is a note to let you know that I've just added the patch titled sysctl: Fix data races in proc_doulongvec_minmax(). to the 5.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: sysctl-fix-data-races-in-proc_doulongvec_minmax.patch and it can be found in the queue-5.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 38f488e5935fb476f1bc42f0e379a2ff33cbfab6 Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> Date: Wed Jul 6 16:39:56 2022 -0700 sysctl: Fix data races in proc_doulongvec_minmax(). [ Upstream commit c31bcc8fb89fc2812663900589c6325ba35d9a65 ] 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_doulongvec_minmax() to use READ_ONCE() and WRITE_ONCE() internally to fix data-races on the sysctl side. For now, proc_doulongvec_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@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/kernel/sysctl.c b/kernel/sysctl.c index a769f64a78ed..7a8899f237a2 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1162,9 +1162,9 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, err = -EINVAL; break; } - *i = val; + WRITE_ONCE(*i, val); } else { - val = convdiv * (*i) / convmul; + val = convdiv * READ_ONCE(*i) / convmul; if (!first) proc_put_char(&buffer, &left, '\t'); proc_put_long(&buffer, &left, val, false);