Commit 264e22af authored by Arnd Bergmann's avatar Arnd Bergmann

Merge tag 'renesas-fixes3-for-v4.13' of...

Merge tag 'renesas-fixes3-for-v4.13' of https://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas into fixes

Pull "Third Round of Renesas ARM Based SoC Fixes for v4.13" from Simon Horman:

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 1c3c5eab ("sched/core: Enable might_sleep() and
smp_processor_id() checks early") and a deadlock occurs.

* tag 'renesas-fixes3-for-v4.13' of https://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas:
  ARM: shmobile: rcar-gen2: Fix deadlock in regulator quirk
parents 48cb953e fce8dc5e
...@@ -67,8 +67,12 @@ static int regulator_quirk_notify(struct notifier_block *nb, ...@@ -67,8 +67,12 @@ static int regulator_quirk_notify(struct notifier_block *nb,
{ {
struct device *dev = data; struct device *dev = data;
struct i2c_client *client; struct i2c_client *client;
static bool done;
u32 mon; u32 mon;
if (done)
return 0;
mon = ioread32(irqc + IRQC_MONITOR); mon = ioread32(irqc + IRQC_MONITOR);
dev_dbg(dev, "%s: %ld, IRQC_MONITOR = 0x%x\n", __func__, action, mon); dev_dbg(dev, "%s: %ld, IRQC_MONITOR = 0x%x\n", __func__, action, mon);
if (mon & REGULATOR_IRQ_MASK) if (mon & REGULATOR_IRQ_MASK)
...@@ -99,7 +103,7 @@ static int regulator_quirk_notify(struct notifier_block *nb, ...@@ -99,7 +103,7 @@ static int regulator_quirk_notify(struct notifier_block *nb,
remove: remove:
dev_info(dev, "IRQ2 is not asserted, removing quirk\n"); dev_info(dev, "IRQ2 is not asserted, removing quirk\n");
bus_unregister_notifier(&i2c_bus_type, nb); done = true;
iounmap(irqc); iounmap(irqc);
return 0; return 0;
} }
......
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