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| author | Paul E. McKenney <paulmck@kernel.org> | 2025-04-23 22:03:59 +0300 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2025-05-09 02:13:27 +0300 |
| commit | aa2cc356f8791438761efa0cb95fd48f3e2721c2 (patch) | |
| tree | dac7567366db8e8774c37a45546c26a462f1ba22 | |
| parent | 084a990ded6337fb603f39b43b67ec68c2da0695 (diff) | |
| download | linux-aa2cc356f8791438761efa0cb95fd48f3e2721c2.tar.xz | |
ratelimit: Force re-initialization when rate-limiting re-enabled
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>
| -rw-r--r-- | lib/ratelimit.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/lib/ratelimit.c b/lib/ratelimit.c index 7a7ba4835639..7d4f4e241213 100644 --- a/lib/ratelimit.c +++ b/lib/ratelimit.c @@ -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; } /* |