This is a note to let you know that I've just added the patch titled sysctl: Fix data races in proc_dointvec(). 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_dointvec.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 8dacdd65cebdd87ea541e368ee00f504dcb6a6f8 Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> Date: Wed Jul 6 16:39:52 2022 -0700 sysctl: Fix data races in proc_dointvec(). [ Upstream commit 1f1be04b4d48a2475ea1aab46a99221bfc5c0968 ] 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_dointvec() to use READ_ONCE() and WRITE_ONCE() internally to fix data-races on the sysctl side. For now, proc_dointvec() 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 830aaf8ca08e..27b3a55dc4bd 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -518,14 +518,14 @@ static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp, if (*negp) { if (*lvalp > (unsigned long) INT_MAX + 1) return -EINVAL; - *valp = -*lvalp; + WRITE_ONCE(*valp, -*lvalp); } else { if (*lvalp > (unsigned long) INT_MAX) return -EINVAL; - *valp = *lvalp; + WRITE_ONCE(*valp, *lvalp); } } else { - int val = *valp; + int val = READ_ONCE(*valp); if (val < 0) { *negp = true; *lvalp = -(unsigned long)val;