| From | Evan Green <> | Date | Sun, 7 Aug 2022 22:07:09 -0700 | Subject | Re: [PATCH v2 03/13] firmware: google: Test spinlock on panic path to avoid lockups |
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On Tue, Jul 19, 2022 at 12:55 PM Guilherme G. Piccoli <gpiccoli@igalia.com> wrote: > > Currently the gsmi driver registers a panic notifier as well as > reboot and die notifiers. The callbacks registered are called in > atomic and very limited context - for instance, panic disables > preemption and local IRQs, also all secondary CPUs (not executing > the panic path) are shutdown. > > With that said, taking a spinlock in this scenario is a dangerous > invitation for lockup scenarios. So, fix that by checking if the > spinlock is free to acquire in the panic notifier callback - if not, > bail-out and avoid a potential hang. > > Fixes: 74c5b31c6618 ("driver: Google EFI SMI") > Cc: Ard Biesheuvel <ardb@kernel.org> > Cc: David Gow <davidgow@google.com> > Cc: Evan Green <evgreen@chromium.org> > Cc: Julius Werner <jwerner@chromium.org> > Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Reviewed-by: Evan Green <evgreen@chromium.org>
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