linux-toradex.git/drivers/regulator/core.c, branch v5.9-rc5

Merge tag 'regulator-fix-v5.9-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator

2020-09-11T18:25:55+00:00

Pull regulator fixes from Mark Brown:
 "The biggest set of fixes here is those from Michał Mirosław fixing
  some locking issues with coupled regulators that are triggered in
  cases where a coupled regulator is used by a device involved in
  fs_reclaim like eMMC storage.

  These are relatively serious for the affected systems, though the
  circumstances where they trigger are very rare"

* tag 'regulator-fix-v5.9-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator:
  regulator: pwm: Fix machine constraints application
  regulator: core: Fix slab-out-of-bounds in regulator_unlock_recursive()
  regulator: remove superfluous lock in regulator_resolve_coupling()
  regulator: cleanup regulator_ena_gpio_free()
  regulator: plug of_node leak in regulator_register()'s error path
  regulator: push allocation in set_consumer_device_supply() out of lock
  regulator: push allocations in create_regulator() outside of lock
  regulator: push allocation in regulator_ena_gpio_request() out of lock
  regulator: push allocation in regulator_init_coupling() outside of lock
  regulator: fix spelling mistake "Cant" -> "Can't"
  regulator: cros-ec-regulator: Add NULL test for devm_kmemdup call

regulator: core: Fix slab-out-of-bounds in regulator_unlock_recursive()

2020-09-01T12:26:28+00:00

The recent commit 7d8196641ee1 ("regulator: Remove pointer table
overallocation") changed the size of coupled_rdevs and now KASAN is able
to detect slab-out-of-bounds problem in regulator_unlock_recursive(),
which is a legit problem caused by a typo in the code. The recursive
unlock function uses n_coupled value of a parent regulator for unlocking
supply regulator, while supply's n_coupled should be used. In practice
problem may only affect platforms that use coupled regulators.

Cc: stable@vger.kernel.org # 5.0+
Fixes: f8702f9e4aa7 ("regulator: core: Use ww_mutex for regulators locking")
Signed-off-by: Dmitry Osipenko 
Link: https://lore.kernel.org/r/20200831204335.19489-1-digetx@gmail.com
Signed-off-by: Mark Brown

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva

regulator: remove superfluous lock in regulator_resolve_coupling()

2020-08-17T12:13:55+00:00

The code modifies rdev, but locks c_rdev instead. Remove the lock
as this is held together by regulator_list_mutex taken in the caller.

Fixes: f9503385b187 ("regulator: core: Mutually resolve regulators coupling")
Signed-off-by: Michał Mirosław 
Reviewed-by: Dmitry Osipenko 
Link: https://lore.kernel.org/r/25eb81cefb37a646f3e44eaaf1d8ae8881cfde52.1597195321.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Mark Brown

regulator: cleanup regulator_ena_gpio_free()

2020-08-17T12:13:54+00:00

Since only regulator_ena_gpio_request() allocates rdev->ena_pin, and it
guarantees that same gpiod gets same pin structure, it is enough to
compare just the pointers. Also we know there can be only one matching
entry on the list. Rework the code take advantage of the facts.

Signed-off-by: Michał Mirosław 
Link: https://lore.kernel.org/r/3ff002c7aa3bd774491af4291a9df23541fcf892.1597195321.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Mark Brown

regulator: plug of_node leak in regulator_register()'s error path

2020-08-17T12:13:53+00:00

By calling device_initialize() earlier and noting that kfree(NULL) is
ok, we can save a bit of code in error handling and plug of_node leak.
Fixed commit already did part of the work.

Fixes: 9177514ce349 ("regulator: fix memory leak on error path of regulator_register()")
Signed-off-by: Michał Mirosław 
Reviewed-by: Vladimir Zapolskiy 
Acked-by: Vladimir Zapolskiy 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/f5035b1b4d40745e66bacd571bbbb5e4644d21a1.1597195321.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Mark Brown

regulator: push allocation in set_consumer_device_supply() out of lock

2020-08-17T12:13:52+00:00

Pull regulator_list_mutex into set_consumer_device_supply() and keep
allocations outside of it. Fourth of the fs_reclaim deadlock case.

Fixes: 45389c47526d ("regulator: core: Add early supply resolution for regulators")
Signed-off-by: Michał Mirosław 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/f0380bdb3d60aeefa9693c4e234d2dcda7e56747.1597195321.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Mark Brown

regulator: push allocations in create_regulator() outside of lock

2020-08-17T12:13:51+00:00

Move all allocations outside of the regulator_lock()ed section.

======================================================
WARNING: possible circular locking dependency detected
5.7.13+ #535 Not tainted
------------------------------------------------------
f2fs_discard-179:7/702 is trying to acquire lock:
c0e5d920 (regulator_list_mutex){+.+.}-{3:3}, at: regulator_lock_dependent+0x54/0x2c0

but task is already holding lock:
cb95b080 (&dcc->cmd_lock){+.+.}-{3:3}, at: __issue_discard_cmd+0xec/0x5f8

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

[...]

-> #3 (fs_reclaim){+.+.}-{0:0}:
       fs_reclaim_acquire.part.11+0x40/0x50
       fs_reclaim_acquire+0x24/0x28
       __kmalloc_track_caller+0x54/0x218
       kstrdup+0x40/0x5c
       create_regulator+0xf4/0x368
       regulator_resolve_supply+0x1a0/0x200
       regulator_register+0x9c8/0x163c

[...]

other info that might help us debug this:

Chain exists of:
  regulator_list_mutex --> &sit_i->sentry_lock --> &dcc->cmd_lock

[...]

Fixes: f8702f9e4aa7 ("regulator: core: Use ww_mutex for regulators locking")
Signed-off-by: Michał Mirosław 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/6eebc99b2474f4ffaa0405b15178ece0e7e4f608.1597195321.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Mark Brown

regulator: push allocation in regulator_ena_gpio_request() out of lock

2020-08-17T12:13:50+00:00

Move another allocation out of regulator_list_mutex-protected region, as
reclaim might want to take the same lock.

WARNING: possible circular locking dependency detected
5.7.13+ #534 Not tainted
------------------------------------------------------
kswapd0/383 is trying to acquire lock:
c0e5d920 (regulator_list_mutex){+.+.}-{3:3}, at: regulator_lock_dependent+0x54/0x2c0

but task is already holding lock:
c0e38518 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x0/0x50

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (fs_reclaim){+.+.}-{0:0}:
       fs_reclaim_acquire.part.11+0x40/0x50
       fs_reclaim_acquire+0x24/0x28
       kmem_cache_alloc_trace+0x40/0x1e8
       regulator_register+0x384/0x1630
       devm_regulator_register+0x50/0x84
       reg_fixed_voltage_probe+0x248/0x35c
[...]
other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(fs_reclaim);
                               lock(regulator_list_mutex);
                               lock(fs_reclaim);
  lock(regulator_list_mutex);

 *** DEADLOCK ***
[...]
2 locks held by kswapd0/383:
 #0: c0e38518 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x0/0x50
 #1: cb70e5e0 (hctx->srcu){....}-{0:0}, at: hctx_lock+0x60/0xb8
[...]

Fixes: 541d052d7215 ("regulator: core: Only support passing enable GPIO descriptors")
[this commit only changes context]
Fixes: f8702f9e4aa7 ("regulator: core: Use ww_mutex for regulators locking")
[this is when the regulator_list_mutex was introduced in reclaim locking path]

Signed-off-by: Michał Mirosław 
Link: https://lore.kernel.org/r/41fe6a9670335721b48e8f5195038c3d67a3bf92.1597195321.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Mark Brown

regulator: push allocation in regulator_init_coupling() outside of lock

2020-08-17T12:13:49+00:00

Allocating memory with regulator_list_mutex held makes lockdep unhappy
when memory pressure makes the system do fs_reclaim on eg. eMMC using
a regulator. Push the lock inside regulator_init_coupling() after the
allocation.

======================================================
WARNING: possible circular locking dependency detected
5.7.13+ #533 Not tainted
------------------------------------------------------
kswapd0/383 is trying to acquire lock:
cca78ca4 (&sbi->write_io[i][j].io_rwsem){++++}-{3:3}, at: __submit_merged_write_cond+0x104/0x154
but task is already holding lock:
c0e38518 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x0/0x50
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (fs_reclaim){+.+.}-{0:0}:
       fs_reclaim_acquire.part.11+0x40/0x50
       fs_reclaim_acquire+0x24/0x28
       __kmalloc+0x54/0x218
       regulator_register+0x860/0x1584
       dummy_regulator_probe+0x60/0xa8
[...]
other info that might help us debug this:

Chain exists of:
  &sbi->write_io[i][j].io_rwsem --> regulator_list_mutex --> fs_reclaim

Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(fs_reclaim);
                               lock(regulator_list_mutex);
                               lock(fs_reclaim);
  lock(&sbi->write_io[i][j].io_rwsem);
 *** DEADLOCK ***

1 lock held by kswapd0/383:
 #0: c0e38518 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x0/0x50
[...]

Fixes: d8ca7d184b33 ("regulator: core: Introduce API for regulators coupling customization")
Signed-off-by: Michał Mirosław 
Reviewed-by: Dmitry Osipenko 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/1a889cf7f61c6429c9e6b34ddcdde99be77a26b6.1597195321.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Mark Brown