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| author | Johan Hovold <johan+linaro@kernel.org> | 2022-12-15 11:46:46 +0100 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2022-12-15 11:56:26 +0000 |
| commit | cb3543cff90a4448ed560ac86c98033ad5fecda9 (patch) | |
| tree | f4e46f8ae36a7d89b533dd3ea478da7d813da0b2 | |
| parent | 0debed5b117d11e33cba52870c4dcb64f5911891 (diff) | |
| download | linux-cb3543cff90a4448ed560ac86c98033ad5fecda9.tar.gz linux-cb3543cff90a4448ed560ac86c98033ad5fecda9.tar.xz | |
regulator: core: fix deadlock on regulator enable
When updating the operating mode as part of regulator enable, the caller
has already locked the regulator tree and drms_uA_update() must not try
to do the same in order not to trigger a deadlock.
The lock inversion is reported by lockdep as:
======================================================
WARNING: possible circular locking dependency detected
6.1.0-next-20221215 #142 Not tainted
------------------------------------------------------
udevd/154 is trying to acquire lock:
ffffc11f123d7e50 (regulator_list_mutex){+.+.}-{3:3}, at: regulator_lock_dependent+0x54/0x280
but task is already holding lock:
ffff80000e4c36e8 (regulator_ww_class_acquire){+.+.}-{0:0}, at: regulator_enable+0x34/0x80
which lock already depends on the new lock.
...
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(regulator_ww_class_acquire);
lock(regulator_list_mutex);
lock(regulator_ww_class_acquire);
lock(regulator_list_mutex);
*** DEADLOCK ***
just before probe of a Qualcomm UFS controller (occasionally) deadlocks
when enabling one of its regulators.
Fixes: 9243a195be7a ("regulator: core: Change voltage setting path")
Fixes: f8702f9e4aa7 ("regulator: core: Use ww_mutex for regulators locking")
Cc: stable@vger.kernel.org # 5.0
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20221215104646.19818-1-johan+linaro@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
| -rw-r--r-- | drivers/regulator/core.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 35a7785c53f6..c661be129818 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -1002,7 +1002,7 @@ static int drms_uA_update(struct regulator_dev *rdev) /* get input voltage */ input_uV = 0; if (rdev->supply) - input_uV = regulator_get_voltage(rdev->supply); + input_uV = regulator_get_voltage_rdev(rdev->supply->rdev); if (input_uV <= 0) input_uV = rdev->constraints->input_uV; |