Messages in this thread | | | Date | Thu, 3 Sep 2015 16:48:16 +0100 | From | "Richard W.M. Jones" <> | Subject | Re: [BUG 4.2-rc8] Interrupt occurs while apply_alternatives() is patching the handler |
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On Thu, Sep 03, 2015 at 12:41:47PM +0200, Thomas Gleixner wrote: > On Thu, 3 Sep 2015, Borislav Petkov wrote: > > On Wed, Sep 02, 2015 at 11:11:55AM +0200, Thomas Gleixner wrote: > > > static void __init_or_module add_nops(void *insns, unsigned int len) > > > { > > > + unsigned long flags; > > > + > > > + local_irq_save(flags); > > > while (len > 0) { > > > > I guess you want to optimize the len==0 case to not disable interrupts > > needlessly: > > > > if (!len) > > return; > > > > local_irq_save(flags); > > while (len > 0) > > ... > > Nah. I rather put the local_irq_save into optimize_nops(). All other > callers of add_nops() are operating on a buffer and use text_poke > after that. Aside of that optimize_nops() is missing a sync_core(). > > Updated patch below.
The V2 patch has got to 900 iterations without hitting the problem. As that is a lot more than without the patch, you can add:
Tested-by: Richard W.M. Jones <rjones@redhat.com>
I will leave it going overnight just in case.
Thanks,
Rich.
-- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top
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