diff options
| author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2022-08-23 10:46:48 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-08-24 13:46:57 +0100 |
| commit | 6bae8ceb90ba76cdba39496db936164fa672b9be (patch) | |
| tree | 6b4e9de4005b45f341c5ef7e66f133e82bb90972 /lib | |
| parent | 61adf447e38664447526698872e21c04623afb8e (diff) | |
| download | lwn-6bae8ceb90ba76cdba39496db936164fa672b9be.tar.gz lwn-6bae8ceb90ba76cdba39496db936164fa672b9be.zip | |
ratelimit: Fix data-races in ___ratelimit().
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>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/ratelimit.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/lib/ratelimit.c b/lib/ratelimit.c index e01a93f46f83..ce945c17980b 100644 --- a/lib/ratelimit.c +++ b/lib/ratelimit.c @@ -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 { |