diff options
| author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2022-07-06 16:39:56 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-07-08 12:10:33 +0100 |
| commit | c31bcc8fb89fc2812663900589c6325ba35d9a65 (patch) | |
| tree | fd2c39eef060fb2a22506063dbd9473747179139 | |
| parent | 2d3b559df3ed39258737789aae2ae7973d205bc1 (diff) | |
sysctl: Fix data races in proc_doulongvec_minmax().
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>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -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 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); |