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Johan Hovold authored
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: 9243a195 ("regulator: core: Change voltage setting path") Fixes: f8702f9e ("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.orgSigned-off-by:
Mark Brown <broonie@kernel.org>
cb3543cf