| Message ID | 20220706234003.66760-6-kuniyu@amazon.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | c31bcc8fb89fc2812663900589c6325ba35d9a65 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | sysctl: Fix data-races around ipv4_table. | expand |
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 379721a03d41..8c55ba01f41b 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1090,9 +1090,9 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, err = -EINVAL; break; } - *i = val; + WRITE_ONCE(*i, val); } else { - val = convdiv * (*i) / convmul; + val = convdiv * READ_ONCE(*i) / convmul; if (!first) proc_put_char(&buffer, &left, '\t'); proc_put_long(&buffer, &left, val, false);
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_doulongvec_minmax() to use READ_ONCE() and WRITE_ONCE() internally to fix data-races on the sysctl side. For now, proc_doulongvec_minmax() 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> --- kernel/sysctl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)