diff options
| author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2022-07-11 17:15:19 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-04-20 12:10:29 +0200 |
| commit | f177b382c33900d0e5a9766493c11a1074076f78 (patch) | |
| tree | 3d9b8afc4aeeb1c6d5d49a3fc7b9f4e4b2e65479 | |
| parent | 56314b90fd43bd2444942bc14a7c5c768ce8ec57 (diff) | |
sysctl: Fix data-races in proc_dou8vec_minmax().
commit 7dee5d7747a69aa2be41f04c6a7ecfe3ac8cdf18 upstream.
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_dou8vec_minmax() to use READ_ONCE() and
WRITE_ONCE() internally to fix data-races on the sysctl side. For now,
proc_dou8vec_minmax() itself is tolerant to a data-race, but we still
need to add annotations on the other subsystem's side.
Fixes: cb9444130662 ("sysctl: add proc_dou8vec_minmax()")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/sysctl.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 43e907f4cac7..d981abea0358 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1109,13 +1109,13 @@ int proc_dou8vec_minmax(struct ctl_table *table, int write, tmp.maxlen = sizeof(val); tmp.data = &val; - val = *data; + val = READ_ONCE(*data); res = do_proc_douintvec(&tmp, write, buffer, lenp, ppos, do_proc_douintvec_minmax_conv, ¶m); if (res) return res; if (write) - *data = val; + WRITE_ONCE(*data, val); return 0; } EXPORT_SYMBOL_GPL(proc_dou8vec_minmax); |