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| author | Geert Uytterhoeven <geert+renesas@glider.be> | 2017-07-12 16:45:20 +0200 |
|---|---|---|
| committer | Simon Horman <horms+renesas@verge.net.au> | 2017-07-29 10:32:52 +0200 |
| commit | fce8dc5e50e44d8f644e0f7854e6d7d518fedb68 (patch) | |
| tree | 92bc3affede983b7ba38cbef8371fc8e6a9e78c5 /arch | |
| parent | Linux 4.12-rc1 (diff) | |
| download | linux-fce8dc5e50e44d8f644e0f7854e6d7d518fedb68.tar.xz linux-fce8dc5e50e44d8f644e0f7854e6d7d518fedb68.zip | |
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>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c b/arch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c index 73e3adbc1330..44438f344dc8 100644 --- a/arch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c +++ b/arch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c @@ -67,8 +67,12 @@ static int regulator_quirk_notify(struct notifier_block *nb, { struct device *dev = data; struct i2c_client *client; + static bool done; u32 mon; + if (done) + return 0; + mon = ioread32(irqc + IRQC_MONITOR); dev_dbg(dev, "%s: %ld, IRQC_MONITOR = 0x%x\n", __func__, action, mon); if (mon & REGULATOR_IRQ_MASK) @@ -99,7 +103,7 @@ static int regulator_quirk_notify(struct notifier_block *nb, remove: dev_info(dev, "IRQ2 is not asserted, removing quirk\n"); - bus_unregister_notifier(&i2c_bus_type, nb); + done = true; iounmap(irqc); return 0; } |