This is a note to let you know that I've just added the patch titled
regulator: core: fix regulator_lock_supply regression
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
regulator-core-fix-regulator_lock_supply-regression.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From bb41897e38c53458a88b271f2fbcd905ee1f9584 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@xxxxxxxx>
Date: Fri, 27 Nov 2015 14:46:41 +0100
Subject: regulator: core: fix regulator_lock_supply regression
From: Arnd Bergmann <arnd@xxxxxxxx>
commit bb41897e38c53458a88b271f2fbcd905ee1f9584 upstream.
As noticed by Geert Uytterhoeven, my patch to avoid a harmless build warning
in regulator_lock_supply() was total crap and introduced a real bug:
> [ BUG: bad unlock balance detected! ]
> kworker/u4:0/6 is trying to release lock (&rdev->mutex) at:
> [<c0247b84>] regulator_set_voltage+0x38/0x50
we still lock the regulator supplies, but not the actual regulators,
so we are missing a lock, and the unlock is unbalanced.
This rectifies it by first locking the regulator device itself before
using the same loop as before to lock its supplies.
Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Fixes: 716fec9d1965 ("[SUBMITTED] regulator: core: avoid unused variable warning")
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/regulator/core.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -140,7 +140,8 @@ static void regulator_lock_supply(struct
{
int i;
- for (i = 0; rdev->supply; rdev = rdev->supply->rdev, i++)
+ mutex_lock(&rdev->mutex);
+ for (i = 1; rdev->supply; rdev = rdev->supply->rdev, i++)
mutex_lock_nested(&rdev->mutex, i);
}
Patches currently in stable-queue which might be from arnd@xxxxxxxx are
queue-4.4/xen-kconfig-don-t-select-input_xen_kbddev_frontend.patch
queue-4.4/asm-generic-futex-re-enable-preemption-in-futex_atomic_cmpxchg_inatomic.patch
queue-4.4/regulator-core-fix-nested-locking-of-supplies.patch
queue-4.4/regulator-core-fix-regulator_lock_supply-regression.patch
queue-4.4/asoc-s3c24xx-use-const-snd_soc_component_driver-pointer.patch
queue-4.4/revert-regulator-core-fix-nested-locking-of-supplies.patch
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