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Commit 4482215f authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Greg Kroah-Hartman
Browse files

ratelimit: Fix data-races in ___ratelimit(). 



[ Upstream commit 6bae8ceb90ba76cdba39496db936164fa672b9be ]

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: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent a90afeab

lib/ratelimit.c

+9 −3
Original line number Diff line number Diff line
@@ -26,10 +26,16 @@ 
 */

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;



	/*
@@ -44,7 +50,7 @@ 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
@@ -56,7 +62,7 @@ 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 {