Third Round of Renesas ARM Based SoC Fixes for v4.13
Fix deadlock in regulator quirk for R-Car Gen 2 SoCs
The da9063/da9210 regulator quirk for R-Car Gen2 boards uses a bus
notifier, and unregisters the notifier when it is no longer needed.
However, a notifier must not be unregistered from within the call chain.
This bug went unnoticed, as blocking_notifier_chain_unregister() didn't
take the semaphore during early boot. This is no longer the case as of
upstream commit 1c3c5eab171590f8 ("sched/core: Enable might_sleep() and
smp_processor_id() checks early") and a deadlock occurs.
ARM: shmobile: rcar-gen2: Fix deadlock in regulator quirk
Simon Horman reported that Koelsch and Lager hang during boot, and
bisected this to commit 1c3c5eab171590f8 ("sched/core: Enable
might_sleep() and smp_processor_id() checks early").
The da9063/da9210 regulator quirk for R-Car Gen2 boards uses a bus
notifier, and unregisters the notifier when it is no longer needed.
However, a notifier must not be unregistered from within the call chain.
This bug went unnoticed, as blocking_notifier_chain_unregister() didn't
take the semaphore during early boot. The aforementioned commit changed
that behavior, leading to a deadlock.
Fix this by removing the call to bus_unregister_notifier(), and keeping
local completion state instead.
Reported-by: Simon Horman <horms+renesas@verge.net.au>
Fixes: 663fbb52159cca6f ("ARM: shmobile: R-Car Gen2: Add da9063/da9210 regulator quirk")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
1 file changed
