diff options
| author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2022-07-06 16:39:57 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-07-08 12:10:33 +0100 |
| commit | e877820877663fbae8cb9582ea597a7230b94df3 (patch) | |
| tree | 9aec0e9f7112b4051872d82b5c19f74af8c62f4d /kernel/sysctl.c | |
| parent | c31bcc8fb89fc2812663900589c6325ba35d9a65 (diff) | |
sysctl: Fix data races in proc_dointvec_jiffies().
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_jiffies() to use READ_ONCE() and
WRITE_ONCE() internally to fix data-races on the sysctl side. For now,
proc_dointvec_jiffies() 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@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/sysctl.c')
| -rw-r--r-- | kernel/sysctl.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 8c55ba01f41b..bf9383d17e1b 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1173,9 +1173,12 @@ static int do_proc_dointvec_jiffies_conv(bool *negp, unsigned long *lvalp, if (write) { if (*lvalp > INT_MAX / HZ) return 1; - *valp = *negp ? -(*lvalp*HZ) : (*lvalp*HZ); + if (*negp) + WRITE_ONCE(*valp, -*lvalp * HZ); + else + WRITE_ONCE(*valp, *lvalp * HZ); } else { - int val = *valp; + int val = READ_ONCE(*valp); unsigned long lval; if (val < 0) { *negp = true; |