2023-06-06 14:53:52

by Thomas Gleixner

Subject: [patch 20/45] signal: Replace BUG_ON()s

These really can be handled gracefully without killing the machine.

Signed-off-by: Thomas Gleixner <[email protected]>
---
kernel/signal.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1932,10 +1932,11 @@ struct sigqueue *sigqueue_alloc(void)

void sigqueue_free(struct sigqueue *q)
{
- unsigned long flags;
spinlock_t *lock = &current->sighand->siglock;
+ unsigned long flags;

- BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
+ if (WARN_ON_ONCE(!(q->flags & SIGQUEUE_PREALLOC)))
+ return;
/*
* We must hold ->siglock while testing q->list
* to serialize with collect_signal() or with
@@ -1963,7 +1964,10 @@ int send_sigqueue(struct sigqueue *q, st
unsigned long flags;
int ret, result;

- BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
+ if (WARN_ON_ONCE(!(q->flags & SIGQUEUE_PREALLOC)))
+ return 0;
+ if (WARN_ON_ONCE(q->info.si_code != SI_TIMER))
+ return 0;

ret = -1;
rcu_read_lock();
@@ -1998,7 +2002,6 @@ int send_sigqueue(struct sigqueue *q, st
* If an SI_TIMER entry is already queue just increment
* the overrun count.
*/
- BUG_ON(q->info.si_code != SI_TIMER);
q->info.si_overrun++;
result = TRACE_SIGNAL_ALREADY_PENDING;
goto out;

2023-07-04 10:44:16

by Frederic Weisbecker

Subject: Re: [patch 20/45] signal: Replace BUG_ON()s

On Tue, Jun 06, 2023 at 04:37:50PM +0200, Thomas Gleixner wrote:
> These really can be handled gracefully without killing the machine.
>
> Signed-off-by: Thomas Gleixner <[email protected]>
> ---
> kernel/signal.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -1932,10 +1932,11 @@ struct sigqueue *sigqueue_alloc(void)
>
> void sigqueue_free(struct sigqueue *q)
> {
> - unsigned long flags;
> spinlock_t *lock = &current->sighand->siglock;
> + unsigned long flags;
>
> - BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
> + if (WARN_ON_ONCE(!(q->flags & SIGQUEUE_PREALLOC)))
> + return;
> /*
> * We must hold ->siglock while testing q->list
> * to serialize with collect_signal() or with
> @@ -1963,7 +1964,10 @@ int send_sigqueue(struct sigqueue *q, st
> unsigned long flags;
> int ret, result;
>
> - BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
> + if (WARN_ON_ONCE(!(q->flags & SIGQUEUE_PREALLOC)))
> + return 0;
> + if (WARN_ON_ONCE(q->info.si_code != SI_TIMER))
> + return 0;

Previously it only forbid _requeuing_ other things than posix timers.
Now it only allows posix timers at all.

But anyway posix timers is the only user so far:

Reviewed-by: Frederic Weisbecker <[email protected]>


>
> ret = -1;
> rcu_read_lock();
> @@ -1998,7 +2002,6 @@ int send_sigqueue(struct sigqueue *q, st
> * If an SI_TIMER entry is already queue just increment
> * the overrun count.
> */
> - BUG_ON(q->info.si_code != SI_TIMER);
> q->info.si_overrun++;
> result = TRACE_SIGNAL_ALREADY_PENDING;
> goto out;
>