diff options
| author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2022-07-06 16:39:52 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-07-08 12:10:32 +0100 |
| commit | 1f1be04b4d48a2475ea1aab46a99221bfc5c0968 (patch) | |
| tree | 2aa39a8fa8df5ab4e128551289ea774822d13c98 /kernel/sysctl.c | |
| parent | 820b8963adaea34a87abbecb906d1f54c0aabfb7 (diff) | |
| download | lwn-1f1be04b4d48a2475ea1aab46a99221bfc5c0968.tar.gz lwn-1f1be04b4d48a2475ea1aab46a99221bfc5c0968.zip | |
sysctl: Fix data races in proc_dointvec().
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@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/sysctl.c')
| -rw-r--r-- | kernel/sysctl.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index e52b6e372c60..c8a05655ae60 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -446,14 +446,14 @@ 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; |