[PATCH v5 14/21] ratelimit: Warn if ->interval or ->burst are negative

[Paul E. McKenney]

From: Petr Mladek <pmladek@xxxxxxxx>

Currently, ___ratelimit() treats a negative ->interval or ->burst as
if it was zero, but this is an accident of the current implementation.
Therefore, splat in this case, which might have the benefit of detecting
use of uninitialized ratelimit_state structures on the one hand or easing
addition of new features on the other.

Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/
Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@xxxxxx/
Signed-off-by: Petr Mladek <pmladek@xxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Cc: Mateusz Guzik <mjguzik@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: John Ogness <john.ogness@xxxxxxxxxxxxx>
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
---
 lib/ratelimit.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/ratelimit.c b/lib/ratelimit.c
index ab8472edeb1d2..6a5cb05413013 100644
--- a/lib/ratelimit.c
+++ b/lib/ratelimit.c
@@ -40,6 +40,7 @@ int ___ratelimit(struct ratelimit_state *rs, const char *func)
 	 * says always limit.
 	 */
 	if (interval <= 0 || burst <= 0) {
+		WARN_ONCE(interval < 0 || burst < 0, "Negative interval (%d) or burst (%d): Uninitialized ratelimit_state structure?\n", interval, burst);
 		ret = interval == 0 || burst > 0;
 		if (!(READ_ONCE(rs->flags) & RATELIMIT_INITIALIZED) || (!interval && !burst) ||
 		    !raw_spin_trylock_irqsave(&rs->lock, flags)) {
-- 
2.40.1