diff options
| author | Johan Hovold <johan+linaro@kernel.org> | 2022-12-15 13:46:46 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-01-14 12:16:24 +0300 |
| commit | 36be7afca1031d0c50b9dda31393123e42acc9f5 (patch) | |
| tree | 524dc1e0c7f19a8fff8eee21763b3276f3b73608 | |
| parent | e12f4c321247bd420664a4771f3d6faa9b45ce96 (diff) | |
| download | linux-36be7afca1031d0c50b9dda31393123e42acc9f5.tar.xz | |
regulator: core: fix deadlock on regulator enable
commit cb3543cff90a4448ed560ac86c98033ad5fecda9 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 df746ba5c1bc..6dd698b2d0af 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -980,7 +980,7 @@ 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; if (input_uV <= 0) { |