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ratelimit: Force re-initialization when rate-limiting re-enabled

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Currently, if rate limiting is disabled, ___ratelimit() does an immediate
early return with no state changes.  This can result in false-positive
drops when re-enabling rate limiting.  Therefore, mark the ratelimit_state
structure "uninitialized" when rate limiting is disabled.

[ paulmck: Apply Petr Mladek feedback. ]

Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/
Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@web.de/
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
This commit is contained in:
Paul E. McKenney
2025-05-08 16:13:27 -07:00
parent 084a990ded
commit aa2cc356f8
1 changed files with 14 additions and 1 deletions
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lib/ratelimit.c
+14 -1
View File
@@ -35,11 +35,24 @@ int ___ratelimit(struct ratelimit_state *rs, const char *func)
unsigned long flags;
int ret;
/*
* Zero interval says never limit, otherwise, non-positive burst
* says always limit.
*/
if (interval <= 0 || burst <= 0) {
ret = interval == 0 || burst > 0;
if (!(READ_ONCE(rs->flags) & RATELIMIT_INITIALIZED) || (!interval && !burst) ||
!raw_spin_trylock_irqsave(&rs->lock, flags)) {
if (!ret)
ratelimit_state_inc_miss(rs);
return ret;
}
/* Force re-initialization once re-enabled. */
rs->flags &= ~RATELIMIT_INITIALIZED;
if (!ret)
ratelimit_state_inc_miss(rs);
return ret;
goto unlock_ret;
}
/*