summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorKuniyuki Iwashima <kuniyu@amazon.com>2022-07-06 16:39:56 -0700
committerDavid S. Miller <davem@davemloft.net>2022-07-08 12:10:33 +0100
commitc31bcc8fb89fc2812663900589c6325ba35d9a65 (patch)
treefd2c39eef060fb2a22506063dbd9473747179139
parent2d3b559df3ed39258737789aae2ae7973d205bc1 (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.c4
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);