linux.git/drivers/regulator/core.c, branch v6.16

regulator: core: fix NULL dereference on unbind due to stale coupling data

2025-06-29T21:10:41+00:00

Failing to reset coupling_desc.n_coupled after freeing coupled_rdevs can
lead to NULL pointer dereference when regulators are accessed post-unbind.

This can happen during runtime PM or other regulator operations that rely
on coupling metadata.

For example, on ridesx4, unbinding the 'reg-dummy' platform device triggers
a panic in regulator_lock_recursive() due to stale coupling state.

Ensure n_coupled is set to 0 to prevent access to invalid pointers.

Signed-off-by: Alessandro Carminati 
Link: https://patch.msgid.link/20250626083809.314842-1-acarmina@redhat.com
Signed-off-by: Mark Brown

regulator: don't compare raw GPIO descriptor pointers

2025-04-09T12:46:58+00:00

There's no API contract saying that two GPIO descriptor pointers
obtained with a call to gpiod_get() (or one of the variants), that refer
to the same physical GPIO pin, always point to the same structure. Use
the dedicated comparator function.

Signed-off-by: Bartosz Golaszewski 
Link: https://patch.msgid.link/20250407-gpiod-is-equal-v1-2-7d85f568ae6e@linaro.org
Signed-off-by: Mark Brown

Merge tag 'mm-nonmm-stable-2025-03-30-18-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-04-01T17:06:52+00:00

Pull non-MM updates from Andrew Morton:

 - The series "powerpc/crash: use generic crashkernel reservation" from
   Sourabh Jain changes powerpc's kexec code to use more of the generic
   layers.

 - The series "get_maintainer: report subsystem status separately" from
   Vlastimil Babka makes some long-requested improvements to the
   get_maintainer output.

 - The series "ucount: Simplify refcounting with rcuref_t" from
   Sebastian Siewior cleans up and optimizing the refcounting in the
   ucount code.

 - The series "reboot: support runtime configuration of emergency
   hw_protection action" from Ahmad Fatoum improves the ability for a
   driver to perform an emergency system shutdown or reboot.

 - The series "Converge on using secs_to_jiffies() part two" from Easwar
   Hariharan performs further migrations from msecs_to_jiffies() to
   secs_to_jiffies().

 - The series "lib/interval_tree: add some test cases and cleanup" from
   Wei Yang permits more userspace testing of kernel library code, adds
   some more tests and performs some cleanups.

 - The series "hung_task: Dump the blocking task stacktrace" from Masami
   Hiramatsu arranges for the hung_task detector to dump the stack of
   the blocking task and not just that of the blocked task.

 - The series "resource: Split and use DEFINE_RES*() macros" from Andy
   Shevchenko provides some cleanups to the resource definition macros.

 - Plus the usual shower of singleton patches - please see the
   individual changelogs for details.

* tag 'mm-nonmm-stable-2025-03-30-18-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (77 commits)
  mailmap: consolidate email addresses of Alexander Sverdlin
  fs/procfs: fix the comment above proc_pid_wchan()
  relay: use kasprintf() instead of fixed buffer formatting
  resource: replace open coded variant of DEFINE_RES()
  resource: replace open coded variants of DEFINE_RES_*_NAMED()
  resource: replace open coded variant of DEFINE_RES_NAMED_DESC()
  resource: split DEFINE_RES_NAMED_DESC() out of DEFINE_RES_NAMED()
  samples: add hung_task detector mutex blocking sample
  hung_task: show the blocker task if the task is hung on mutex
  kexec_core: accept unaccepted kexec segments' destination addresses
  watchdog/perf: optimize bytes copied and remove manual NUL-termination
  lib/interval_tree: fix the comment of interval_tree_span_iter_next_gap()
  lib/interval_tree: skip the check before go to the right subtree
  lib/interval_tree: add test case for span iteration
  lib/interval_tree: add test case for interval_tree_iter_xxx() helpers
  lib/rbtree: add random seed
  lib/rbtree: split tests
  lib/rbtree: enable userland test suite for rbtree related data structure
  checkpatch: describe --min-conf-desc-length
  scripts/gdb/symbols: determine KASLR offset on s390
  ...

regulator: allow user configuration of hardware protection action

2025-03-17T06:24:14+00:00

When the core detects permanent regulator hardware failure or imminent
power failure of a critical supply, it will call hw_protection_shutdown in
an attempt to do a limited orderly shutdown followed by powering off the
system.

This doesn't work out well for many unattended embedded systems that don't
have support for shutdown and that power on automatically when power is
supplied:

  - A brief power cycle gets detected by the driver
  - The kernel powers down the system and SoC goes into shutdown mode
  - Power is restored
  - The system remains oblivious to the restored power
  - System needs to be manually power cycled for a duration long enough
    to drain the capacitors

Allow users to fix this by calling the newly introduced
hw_protection_trigger() instead: This way the hw_protection commandline or
sysfs parameter is used to dictate the policy of dealing with the
regulator fault.

Link: https://lkml.kernel.org/r/20250217-hw_protection-reboot-v3-8-e1c09b090c0c@pengutronix.de
Signed-off-by: Ahmad Fatoum 
Reviewed-by: Tzung-Bi Shih 
Reviewed-by: Matti Vaittinen 
Cc: Benson Leung 
Cc: Daniel Lezcano 
Cc: Fabio Estevam 
Cc: Guenter Roeck 
Cc: Jonathan Corbet 
Cc: Liam Girdwood 
Cc: Lukasz Luba 
Cc: Mark Brown 
Cc: Matteo Croce 
Cc: "Rafael J. Wysocki" 
Cc: Rob Herring (Arm) 
Cc: Rui Zhang 
Cc: Sascha Hauer 
Cc: "Serge E. Hallyn" 
Signed-off-by: Andrew Morton

regulator: check that dummy regulator has been probed before using it

2025-03-13T12:46:17+00:00

Due to asynchronous driver probing there is a chance that the dummy
regulator hasn't already been probed when first accessing it.

Cc: stable@vger.kernel.org
Signed-off-by: Christian Eggers 
Link: https://patch.msgid.link/20250313103051.32430-3-ceggers@arri.de
Signed-off-by: Mark Brown

regulator: core: Fix deadlock in create_regulator()

2025-03-05T16:35:11+00:00

Currently, we are unnecessarily holding a regulator_ww_class_mutex lock
when creating debugfs entries for a newly created regulator. This was
brought up as a concern in the discussion in commit cba6cfdc7c3f
("regulator: core: Avoid lockdep reports when resolving supplies").

This causes the following lockdep splat after executing
`ls /sys/kernel/debug` on my platform:

  ======================================================
  WARNING: possible circular locking dependency detected
  5.15.167-axis9-devel #1 Tainted: G           O
  ------------------------------------------------------
  ls/2146 is trying to acquire lock:
  ffffff803a562918 (&mm->mmap_lock){++++}-{3:3}, at: __might_fault+0x40/0x88

  but task is already holding lock:
  ffffff80014497f8 (&sb->s_type->i_mutex_key#3){++++}-{3:3}, at: iterate_dir+0x50/0x1f4

  which lock already depends on the new lock.

  [...]

  Chain exists of:
    &mm->mmap_lock --> regulator_ww_class_mutex --> &sb->s_type->i_mutex_key#3

   Possible unsafe locking scenario:

         CPU0                    CPU1
         ----                    ----
    lock(&sb->s_type->i_mutex_key#3);
                                 lock(regulator_ww_class_mutex);
                                 lock(&sb->s_type->i_mutex_key#3);
    lock(&mm->mmap_lock);

   *** DEADLOCK ***

This lock dependency still exists on the latest kernel and using a newer
non-tainted kernel would still cause this problem.

Fix by moving sysfs symlinking and creation of debugfs entries to after
the release of the regulator lock.

Fixes: cba6cfdc7c3f ("regulator: core: Avoid lockdep reports when resolving supplies")
Fixes: eaa7995c529b ("regulator: core: avoid regulator_resolve_supply() race condition")
Signed-off-by: Ludvig Pärsson 
Link: https://patch.msgid.link/20250305-regulator_lockdep_fix-v1-1-ab938b12e790@axis.com
Signed-off-by: Mark Brown

regulator: core: let dt properties override driver init_data

2025-02-11T16:29:01+00:00

This reverts commit cd7a38c40b231350a3cd0fd774f4e6bb68c4b411.

When submitting the change above, it was thought that the origin of the
init_data should be a clear choice, from the driver or from DT but not
both.

It turns out some devices, such as qcom-msm8974-lge-nexus5-hammerhead,
relied on the old behaviour to override the init_data provided by the
driver, making it some kind of default if none is provided by the platform.

Using the init_data provided by the driver when it is present broke these
devices so revert the change to fixup the situation and add a comment
to make things a bit more clear

Reported-by: Luca Weiss 
Closes: https://lore.kernel.org/lkml/5857103.DvuYhMxLoT@lucaweiss.eu
Fixes: cd7a38c40b23 ("regulator: core: do not silently ignore provided init_data")
Signed-off-by: Jerome Brunet 
Link: https://patch.msgid.link/20250211-regulator-init-data-fixup-v1-1-5ce1c6cff990@baylibre.com
Signed-off-by: Mark Brown

regulator: core: Add missing newline character

2025-01-22T14:29:29+00:00

dev_err_probe() error messages need newline character.

Fixes: 6eabfc018e8d ("regulator: core: Allow specifying an initial load w/ the bulk API")
Signed-off-by: Alexander Stein 
Link: https://patch.msgid.link/20250122072019.1926093-1-alexander.stein@ew.tq-group.com
Signed-off-by: Mark Brown

regulator: Add support for power budget

2025-01-17T17:48:54+00:00

Introduce power budget management for the regulator device. Enable tracking
of available power capacity by providing helpers to request and release
power budget allocations.

Signed-off-by: Kory Maincent 
Link: https://patch.msgid.link/20250115-feature_regulator_pw_budget-v2-1-0a44b949e6bc@bootlin.com
Signed-off-by: Mark Brown

regulator: core: Resolve supply using of_node from regulator_config

2025-01-09T16:52:30+00:00

Previously, the regulator core resolved its supply only from the parent
device or its children, ignoring the of_node specified in the
regulator_config structure.
This behavior causes issues in scenarios where multiple regulator devices
are registered for components described as children of a controller, each
with their own specific regulator supply.

For instance, in a PSE controller with multiple PIs (Power Interfaces),
each PI may have a distinct regulator supply. However, the regulator core
would incorrectly use the PSE controller node or its first child to look up
the regulator supply, rather than the node specified by the
regulator_config->of_node for the PI.

This update modifies the behavior to prioritize the of_node in
regulator_config for resolving the supply. This ensures correct resolution
of the power supply for each device. If no supply is found in the provided
of_node, the core falls back to searching within the parent device as
before.

Reviewed-by: Oleksij Rempel 
Signed-off-by: Kory Maincent 
Link: https://patch.msgid.link/20250109-b4-feature_poe_arrange-v2-13-55ded947b510@bootlin.com
Signed-off-by: Mark Brown