On Mon, Mar 15 2021 at 16:44, Eugeniu Rosca wrote:
> From: Dirk Behme <dirk.be...@de.bosch.com>
>
> In case this BUG() is hit, it helps debugging a lot to get an idea
> what tasklet is the root cause. So, be slightly more verbose here.
>
> Signed-off-by: Dirk Behme <dirk.be...@de.bosch.com>
> Signed-off-by: Eugeniu Rosca <ero...@de.adit-jv.com>
> ---
> kernel/softirq.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/softirq.c b/kernel/softirq.c
> index 9908ec4a9bfe..a6b602ad48d6 100644
> --- a/kernel/softirq.c
> +++ b/kernel/softirq.c
> @@ -550,9 +550,13 @@ static void tasklet_action_common(struct softirq_action
> *a,
>
> if (tasklet_trylock(t)) {
> if (!atomic_read(&t->count)) {
> - if (!test_and_clear_bit(TASKLET_STATE_SCHED,
> - &t->state))
> + if (!test_and_clear_bit(TASKLET_STATE_SCHED,
> &t->state)) {
> + if (t->use_callback)
> + pr_emerg("tasklet failed, cb:
> %pS\n", t->callback);
> + else
> + pr_emerg("tasklet failed, func:
> %pS\n", t->func);
> BUG();
> + }
> if (t->use_callback)
> t->callback(t);
> else
This belongs into unreadable land and actually the BUG() should just be
replaced by a WARN_ONCE(). Something like the below. Hmm?
Thanks,
tglx
---
+static bool tasklet_should_run(struct tasklet_struct *t)
+{
+ if (test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
+ return true;
+
+ WARN_ONCE(1, "tasklet SCHED state not set: %s %pS\n",
+ t->use_callback ? "callback" : "func",
+ t->use_callback ? (void*)t->callback : (void*)t->func);
+
+ return false;
+}
+
static void tasklet_action_common(struct softirq_action *a,
struct tasklet_head *tl_head,
unsigned int softirq_nr)
@@ -550,13 +562,12 @@ static void tasklet_action_common(struct
if (tasklet_trylock(t)) {
if (!atomic_read(&t->count)) {
- if (!test_and_clear_bit(TASKLET_STATE_SCHED,
- &t->state))
- BUG();
- if (t->use_callback)
- t->callback(t);
- else
- t->func(t->data);
+ if (tasklet_should_run(t)) {
+ if (t->use_callback)
+ t->callback(t);
+ else
+ t->func(t->data);
+ }
tasklet_unlock(t);
continue;
}
