Commit 264e22af authored Aug 04, 2017 by 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

arch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -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;
		}

Admin message