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  1. 17 Aug, 2020 2 commits
    • Michał Mirosław's avatar
      regulator: push allocation in regulator_ena_gpio_request() out of lock · 467bf301
      Michał Mirosław authored 
      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: 541d052d ("regulator: core: Only support passing enable GPIO descriptors")
[this commit only changes context]
Fixes: f8702f9e ("regulator: core: Use ww_mutex for regulators locking")
[this is when the regulator_list_mutex was introduced in reclaim locking path]
Signed-off-by: default avatarMichał Mirosław <mirq-linux@rere.qmqm.pl>
Link: https://lore.kernel.org/r/41fe6a9670335721b48e8f5195038c3d67a3bf92.1597195321.git.mirq-linux@rere.qmqm.plSigned-off-by: default avatarMark Brown <broonie@kernel.org>
      467bf301
    • Michał Mirosław's avatar
      regulator: push allocation in regulator_init_coupling() outside of lock · 73a32129
      Michał Mirosław authored 
      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: d8ca7d18 ("regulator: core: Introduce API for regulators coupling customization")
Signed-off-by: default avatarMichał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: default avatarDmitry Osipenko <digetx@gmail.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/1a889cf7f61c6429c9e6b34ddcdde99be77a26b6.1597195321.git.mirq-linux@rere.qmqm.plSigned-off-by: default avatarMark Brown <broonie@kernel.org>
      73a32129
  3. 10 Aug, 2020 1 commit
  5. 04 Aug, 2020 1 commit
  7. 30 Jul, 2020 1 commit
  9. 28 Jul, 2020 1 commit
  11. 27 Jul, 2020 2 commits
  13. 24 Jul, 2020 1 commit
    • Vladimir Zapolskiy's avatar
      regulator: fix memory leak on error path of regulator_register() · 9177514c
      Vladimir Zapolskiy authored 
      The change corrects registration and deregistration on error path
of a regulator, the problem was manifested by a reported memory
leak on deferred probe:

    as3722-regulator as3722-regulator: regulator 13 register failed -517

    # cat /sys/kernel/debug/kmemleak
    unreferenced object 0xecc43740 (size 64):
      comm "swapper/0", pid 1, jiffies 4294937640 (age 712.880s)
      hex dump (first 32 bytes):
        72 65 67 75 6c 61 74 6f 72 2e 32 34 00 5a 5a 5a  regulator.24.ZZZ
        5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a  ZZZZZZZZZZZZZZZZ
      backtrace:
        [<0c4c3d1c>] __kmalloc_track_caller+0x15c/0x2c0
        [<40c0ad48>] kvasprintf+0x64/0xd4
        [<109abd29>] kvasprintf_const+0x70/0x84
        [<c4215946>] kobject_set_name_vargs+0x34/0xa8
        [<62282ea2>] dev_set_name+0x40/0x64
        [<a39b6757>] regulator_register+0x3a4/0x1344
        [<16a9543f>] devm_regulator_register+0x4c/0x84
        [<51a4c6a1>] as3722_regulator_probe+0x294/0x754
        ...

The memory leak problem was introduced as a side ef another fix in
regulator_register() error path, I believe that the proper fix is
to decouple device_register() function into its two compounds and
initialize a struct device before assigning any values to its fields
and then using it before actual registration of a device happens.

This lets to call put_device() safely after initialization, and, since
now a release callback is called, kfree(rdev->constraints) shall be
removed to exclude a double free condition.

Fixes: a3cde953 ("regulator: core: fix regulator_register() error paths to properly release rdev")
Signed-off-by: default avatarVladimir Zapolskiy <vz@mleia.com>
Cc: Wen Yang <wenyang@linux.alibaba.com>
Link: https://lore.kernel.org/r/20200724005013.23278-1-vz@mleia.comSigned-off-by: default avatarMark Brown <broonie@kernel.org>
      9177514c
  15. 22 Jul, 2020 1 commit
  17. 21 Jul, 2020 1 commit
  19. 20 Jul, 2020 3 commits
    • Mark Brown's avatar
      Merge series "regulator_sync_state() support" from Saravana Kannan <saravanak@google.com>: · f70e472d
      Mark Brown authored 
      Consider the following example:
- regulator-X is provided by device-X.
- regulator-X is a supplier to device-A, device-B and device-C.
- device-A is off/inactive from boot.
- device-B and device-C are left on/active by the bootloader
- regulator-X is left on boot by the bootloader at 2000 mV to supply
  device-B and device-C.

Example boot sequence 1:
1. device-X is probed successfully.
2. device-A is probed by driver-A
   a. driver-A gets regulator-X
   b. driver-A votes on regulator-X
   c. driver-A initializes device-A
   d. driver-A votes off regulator-X
   e. regulator-X is turned off.
3. System crashes or device-B and device-C become unreliable because
   regulator-X was turned off without following the proper quiescing
   steps for device-B and device-C.

Example boot sequence 2:
1. device-X is probed successfully.
2. device-B is probed by driver-B
   a. driver-B gets regulator-X
   b. driver-B votes on regulator-X
   c. driver-B lowers device-B performance point.
   d. driver-B lowers voltage vote to 1000 mV.
   e. regulator-X voltage is lowered to 1000 mV.
3. System crashes or device-C becomes unreliable because regulator-X
   voltage was lowered to 1000 mV when device-C still needed it at 2000 mV

This patch series makes sure these examples are handled correctly and
system crash or device instability is avoided and the system remains
usable.

More details provided in the commit texts.

v2->v3:
Patch 2/4 - No functional change. Simple refactor.
Patch 3/4
- Was Patch 2/2 in v2.
- Rewrote commit text to hopefully address all previous points.
- Renamed variable/functions. Hope it's clearer.
- Added more comments.
- Added logging
- Fixed timeout functionality.
- Handle exclusive consumers properly
- Handle coupled regulators properly
Patch 4/4 - Prevents voltage from going too low during boot.

v1->v2:
Patch 1/2
- New patch
Patch 2/2
- This was the only patch in v1
- Made the late_initcall_sync timeout a commandline param
- If timeout is set, we also give up waiting for all consumers after
  the timeout expires.
- Made every regulator driver add sync_state() support

Saravana Kannan (4):
  driver core: Add dev_set_drv_sync_state()
  regulator: core: Add destroy_regulator()
  regulator: core: Add basic enable/disable support for sync_state()
    callbacks
  regulator: core: Add voltage support for sync_state() callbacks

 drivers/regulator/core.c         | 200 ++++++++++++++++++++++++++++---
 include/linux/device.h           |  12 ++
 include/linux/regulator/driver.h |   2 +
 3 files changed, 198 insertions(+), 16 deletions(-)

--
2.28.0.rc0.105.gf9edc3c819-goog
      f70e472d
    • Chen-Yu Tsai's avatar
      regulator: gpio: Honor regulator-boot-on property · 3acff11c
      Chen-Yu Tsai authored 
      When requesting the enable GPIO, the driver should do so with the
correct output level matching some expected state. This is especially
important if the regulator is a critical one, such as a supply for
the boot CPU. This is currently done by checking for the enable-at-boot
property, but this is not documented in the device tree binding, nor
does it match the common regulator properties.

Honor the common regulator-boot-on property by checking the boot_on
constraint setting within the DT probe path. This is the same as what
is done in the fixed regulator driver.

Also add a comment stating that the enable-at-boot property should not
be used.

Fixes: 006694d0 ("regulator: gpio-regulator: Allow use of GPIO controlled regulators though DT")
Signed-off-by: default avatarChen-Yu Tsai <wens@csie.org>
Link: https://lore.kernel.org/r/20200720132809.26908-1-wens@kernel.orgSigned-off-by: default avatarMark Brown <broonie@kernel.org>
      3acff11c
    • Saravana Kannan's avatar
      regulator: core: Add destroy_regulator() · e1794aa4
      Saravana Kannan authored 
      Part of the regulator_get() code is already factored out into
create_regulator(). This patch factors out some of the regulator_put()
code into destroy_regulator() so that create_regulator() has a
corresponding unwind function. Subsequent patches will use this
function.
Signed-off-by: default avatarSaravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200716042053.1927676-3-saravanak@google.comSigned-off-by: default avatarMark Brown <broonie@kernel.org>
      e1794aa4
  21. 16 Jul, 2020 1 commit
  23. 15 Jul, 2020 3 commits
  25. 13 Jul, 2020 1 commit
  27. 08 Jul, 2020 3 commits
  29. 07 Jul, 2020 1 commit
  31. 06 Jul, 2020 4 commits
  33. 03 Jul, 2020 2 commits
  35. 02 Jul, 2020 11 commits
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