Re: [PATCH 4.14-rt] Fix wrong-variable use in irq_set_affinity_notifier

[Joe Korty <joe.korty@concurrent-rt.com>]

On Tue, Feb 11, 2020 at 06:49:15PM +0100, Sebastian Andrzej Siewior wrote:
> On 2020-02-11 09:00:07 [-0500], Joe Korty wrote:
> > 4.14-rt: Fix wrong-variable use in irq_set_affinity_notifier.
> > 
> > The bug was introduced in the 4.14-rt patch
> >  
> >    0461-genirq-Handle-missing-work_struct-in-irq_set_affinit.patch
> > 
> > The symptom is a NULL pointer panic in the i40e driver on
> > system shutdown.
> ???
> > 4.19-rt and above do not have this problem due to a refactoring.
> 
> That would be Tom's to pick. Is v4.14-RT the only one affected? I was
> under the impression that we fixed it already in each stable rt tree.

A quick grep of all the -rt patch files in kernel.org/../projects/rt, newer
than May, 2019, shows that 4.14 is the only one needing a fix.

    patch-4.14.170-rt74.patch.xz:
    +		kthread_cancel_work_sync(&notify->work);
    patch-4.4.208-rt191.patch.xz:
    patch-3.18.18-rt15.patch.xz:
    patch-5.0.21-rt16.patch.xz:
    patch-5.2.21-rt14.patch.xz:
    patch-5.4.17-rt9.patch.xz:
    patch-4.9.201-rt134.patch.xz:

> 
> > Signed-off-by: Joe Korty <Joe.Korty@concurrent-rt.com>
> > 
> > Index: b/kernel/irq/manage.c
> > ===================================================================
> > --- a/kernel/irq/manage.c
> > +++ b/kernel/irq/manage.c
> > @@ -353,7 +353,7 @@ irq_set_affinity_notifier(unsigned int i
> >  
> >  	if (old_notify) {
> >  #ifdef CONFIG_PREEMPT_RT_BASE
> > -		kthread_cancel_work_sync(&notify->work);
> > +		kthread_cancel_work_sync(&old_notify->work);
> >  #else
> >  		cancel_work_sync(&old_notify->work);
> >  #endif
> 
> Sebastian

-- 

Regards,
Joe

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Joe Korty
Concurrent Real-Time, Inc.
2881 Gateway Drive
Pompano Beach, Florida USA 33069
Phone: +1 954.973.5262
Email: joe.korty@concurrent-rt.com
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