ratelimit: Fix data-races in ___ratelimit().

[ Upstream commit 6bae8ceb90 ]

While reading rs->interval and rs->burst, they can be changed
concurrently via sysctl (e.g. net_ratelimit_state).  Thus, we
need to add READ_ONCE() to their readers.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Kuniyuki Iwashima 2022-08-23 10:46:48 -07:00 committed by Greg Kroah-Hartman
parent f5a07560d4
commit 4cf771176d

View File

@ -27,10 +27,16 @@
*/
int ___ratelimit(struct ratelimit_state *rs, const char *func)
{
/* Paired with WRITE_ONCE() in .proc_handler().
* Changing two values seperately could be inconsistent
* and some message could be lost. (See: net_ratelimit_state).
*/
int interval = READ_ONCE(rs->interval);
int burst = READ_ONCE(rs->burst);
unsigned long flags;
int ret;
if (!rs->interval)
if (!interval)
return 1;
/*
@ -45,7 +51,7 @@ int ___ratelimit(struct ratelimit_state *rs, const char *func)
if (!rs->begin)
rs->begin = jiffies;
if (time_is_before_jiffies(rs->begin + rs->interval)) {
if (time_is_before_jiffies(rs->begin + interval)) {
if (rs->missed) {
if (!(rs->flags & RATELIMIT_MSG_ON_RELEASE)) {
printk_deferred(KERN_WARNING
@ -57,7 +63,7 @@ int ___ratelimit(struct ratelimit_state *rs, const char *func)
rs->begin = jiffies;
rs->printed = 0;
}
if (rs->burst && rs->burst > rs->printed) {
if (burst && burst > rs->printed) {
rs->printed++;
ret = 1;
} else {