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authorGeert Uytterhoeven <geert+renesas@glider.be>2017-07-12 16:45:20 +0200
committerSimon Horman <horms+renesas@verge.net.au>2017-07-29 10:32:52 +0200
commitfce8dc5e50e44d8f644e0f7854e6d7d518fedb68 (patch)
tree92bc3affede983b7ba38cbef8371fc8e6a9e78c5 /arch
parent2ea659a9ef488125eb46da6eb571de5eae5c43f6 (diff)
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.c6
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;
}