Re: [PATCH v4 0/1] Use mutex_lock_killable() in ap_bus_force_rescan()

[Vasily Gorbik <gor@linux.ibm.com>]

On Thu, Jul 09, 2026 at 09:24:59AM +0200, Harald Freudenberger wrote:
> A deep dive into the AP bus code and zcrypt device driver about the
> usage of mutex locking showed that there is one questionable call in
> ap_bus.c in function ap_bus_force_rescan(). This function may be
> called in kernel and process context. In both contexts only one info
> is important: was there a AP bus scan running and did it result in
> some updates on the AP devices. So only true/false is returned but no
> info like -EINTR. But still the mutex lock call should be
> interruptible to be able to kill a user space program blocked forever
> on this. So this patch replaces mutex_lock_interruptible() with
> mutex_lock_killable() to  be able to handle SIGKILL especially in user
> space process context.
> 
> v1 - initial version
> v2 - with v1 came up some discussion from Holger and Heiko. Heiko especially
>      wanted me to rephrase the header of the patch.
>      However v2 went out with a rewrite of the code as discussed and suggested
>      by Holger but Heikos complain were not addressed.
> v3 - now and finally I rephrased the patch header. Let's see what feedback
>      I'll get for this now.
> v4 - Rephrased the subject, Reviewed-by updated
> 
> Harald Freudenberger (1):
>   s390/ap: Use mutex_lock_killable() in ap_bus_force_rescan()
> 
>  drivers/s390/crypto/ap_bus.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Applied, thank you!