* Mark Rutland <mark.rutl...@arm.com> wrote:
> The counters in struct lockdep_stats are all (signed) ints. For some
> counters (e.g. hardirqs_on_events, hardirqs_off_events), it's easy to
> trigger an overflow in a short period of time, rendering the information
> exposed under /proc/lockdep_stats erroneous, and causing UBSAN to
> scream.
> diff --git a/kernel/locking/lockdep_internals.h
> b/kernel/locking/lockdep_internals.h
> index c2b8849..9fd970e 100644
> --- a/kernel/locking/lockdep_internals.h
> +++ b/kernel/locking/lockdep_internals.h
> @@ -132,23 +132,23 @@ extern void get_usage_chars(struct lock_class *class,
> * and we want to avoid too much cache bouncing.
> */
> struct lockdep_stats {
> - int chain_lookup_hits;
> - int chain_lookup_misses;
> - int hardirqs_on_events;
> - int hardirqs_off_events;
> - int redundant_hardirqs_on;
> - int redundant_hardirqs_off;
> - int softirqs_on_events;
> - int softirqs_off_events;
> - int redundant_softirqs_on;
> - int redundant_softirqs_off;
> - int nr_unused_locks;
> - int nr_cyclic_checks;
> - int nr_cyclic_check_recursions;
> - int nr_find_usage_forwards_checks;
> - int nr_find_usage_forwards_recursions;
> - int nr_find_usage_backwards_checks;
> - int nr_find_usage_backwards_recursions;
> + unsigned long chain_lookup_hits;
> + unsigned long chain_lookup_misses;
> + unsigned long hardirqs_on_events;
> + unsigned long hardirqs_off_events;
> + unsigned long redundant_hardirqs_on;
> + unsigned long redundant_hardirqs_off;
> + unsigned long softirqs_on_events;
> + unsigned long softirqs_off_events;
> + unsigned long redundant_softirqs_on;
> + unsigned long redundant_softirqs_off;
> + unsigned long nr_unused_locks;
> + unsigned long nr_cyclic_checks;
> + unsigned long nr_cyclic_check_recursions;
> + unsigned long nr_find_usage_forwards_checks;
> + unsigned long nr_find_usage_forwards_recursions;
> + unsigned long nr_find_usage_backwards_checks;
> + unsigned long nr_find_usage_backwards_recursions;
Presumably it's just as easy to overflow on 32-bit CPUs, so this should
probably
be u64 or such.
Thanks,
Ingo
