From 87fe29b61f9522a3d7b60a4580851f548558186f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micha=C5=82=20Miros=C5=82aw?= Date: Wed, 12 Aug 2020 03:31:35 +0200 Subject: [PATCH] regulator: push allocations in create_regulator() outside of lock MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Move all allocations outside of the regulator_lock()ed section. ====================================================== WARNING: possible circular locking dependency detected 5.7.13+ #535 Not tainted ------------------------------------------------------ f2fs_discard-179:7/702 is trying to acquire lock: c0e5d920 (regulator_list_mutex){+.+.}-{3:3}, at: regulator_lock_dependent+0x54/0x2c0 but task is already holding lock: cb95b080 (&dcc->cmd_lock){+.+.}-{3:3}, at: __issue_discard_cmd+0xec/0x5f8 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: [...] -> #3 (fs_reclaim){+.+.}-{0:0}: fs_reclaim_acquire.part.11+0x40/0x50 fs_reclaim_acquire+0x24/0x28 __kmalloc_track_caller+0x54/0x218 kstrdup+0x40/0x5c create_regulator+0xf4/0x368 regulator_resolve_supply+0x1a0/0x200 regulator_register+0x9c8/0x163c [...] other info that might help us debug this: Chain exists of: regulator_list_mutex --> &sit_i->sentry_lock --> &dcc->cmd_lock [...] Fixes: f8702f9e4aa7 ("regulator: core: Use ww_mutex for regulators locking") Signed-off-by: Michał Mirosław Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/6eebc99b2474f4ffaa0405b15178ece0e7e4f608.1597195321.git.mirq-linux@rere.qmqm.pl Signed-off-by: Mark Brown --- drivers/regulator/core.c | 53 +++++++++++++++++++++------------------- 1 file changed, 28 insertions(+), 25 deletions(-) diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 62fcf1ebbd04..64a8c9444dcd 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -1580,44 +1580,53 @@ static struct regulator *create_regulator(struct regulator_dev *rdev, const char *supply_name) { struct regulator *regulator; - char buf[REG_STR_SIZE]; - int err, size; + int err; + + if (dev) { + char buf[REG_STR_SIZE]; + int size; + + size = snprintf(buf, REG_STR_SIZE, "%s-%s", + dev->kobj.name, supply_name); + if (size >= REG_STR_SIZE) + return NULL; + + supply_name = kstrdup(buf, GFP_KERNEL); + if (supply_name == NULL) + return NULL; + } else { + supply_name = kstrdup_const(supply_name, GFP_KERNEL); + if (supply_name == NULL) + return NULL; + } regulator = kzalloc(sizeof(*regulator), GFP_KERNEL); - if (regulator == NULL) + if (regulator == NULL) { + kfree(supply_name); return NULL; + } + + regulator->rdev = rdev; + regulator->supply_name = supply_name; regulator_lock(rdev); - regulator->rdev = rdev; list_add(®ulator->list, &rdev->consumer_list); + regulator_unlock(rdev); if (dev) { regulator->dev = dev; /* Add a link to the device sysfs entry */ - size = snprintf(buf, REG_STR_SIZE, "%s-%s", - dev->kobj.name, supply_name); - if (size >= REG_STR_SIZE) - goto overflow_err; - - regulator->supply_name = kstrdup(buf, GFP_KERNEL); - if (regulator->supply_name == NULL) - goto overflow_err; - err = sysfs_create_link_nowarn(&rdev->dev.kobj, &dev->kobj, - buf); + supply_name); if (err) { rdev_dbg(rdev, "could not add device link %s err %d\n", dev->kobj.name, err); /* non-fatal */ } - } else { - regulator->supply_name = kstrdup_const(supply_name, GFP_KERNEL); - if (regulator->supply_name == NULL) - goto overflow_err; } - regulator->debugfs = debugfs_create_dir(regulator->supply_name, + regulator->debugfs = debugfs_create_dir(supply_name, rdev->debugfs); if (!regulator->debugfs) { rdev_dbg(rdev, "Failed to create debugfs directory\n"); @@ -1642,13 +1651,7 @@ static struct regulator *create_regulator(struct regulator_dev *rdev, _regulator_is_enabled(rdev)) regulator->always_on = true; - regulator_unlock(rdev); return regulator; -overflow_err: - list_del(®ulator->list); - kfree(regulator); - regulator_unlock(rdev); - return NULL; } static int _regulator_get_enable_time(struct regulator_dev *rdev)