This is a note to let you know that I've just added the patch titled sysctl: Fix data races in proc_douintvec(). 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_douintvec.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 ad1caaff9f0668d52985908887491e119c0ecf02 Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> Date: Wed Jul 6 16:39:53 2022 -0700 sysctl: Fix data races in proc_douintvec(). [ Upstream commit 4762b532ec9539755aab61445d5da6e1926ccb99 ] 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() to use READ_ONCE() and WRITE_ONCE() internally to fix data-races on the sysctl side. For now, proc_douintvec() itself is tolerant to a data-race, but we still need to add annotations on the other subsystem's side. Fixes: e7d316a02f68 ("sysctl: handle error writing UINT_MAX to u32 fields") 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 27b3a55dc4bd..6c61e2992fed 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -544,9 +544,9 @@ static int do_proc_douintvec_conv(unsigned long *lvalp, if (write) { if (*lvalp > UINT_MAX) return -EINVAL; - *valp = *lvalp; + WRITE_ONCE(*valp, *lvalp); } else { - unsigned int val = *valp; + unsigned int val = READ_ONCE(*valp); *lvalp = (unsigned long)val; } return 0;