From: Kuniyuki Iwashima kuniyu@amazon.com
[ 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: 1da177e4c3f4 ("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 --- lib/ratelimit.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/lib/ratelimit.c b/lib/ratelimit.c index d01f471352390..b805702de84dd 100644 --- a/lib/ratelimit.c +++ b/lib/ratelimit.c @@ -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 {