diff options
| author | Jim Lin <jilin@nvidia.com> | 2015-01-08 20:25:05 +0800 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2015-01-29 15:44:55 +0100 |
| commit | 36b8f27a491d339ad4684c7560a398bcf6eda0d8 (patch) | |
| tree | a612c09b4741b41fdfc4fc82c80c262d4b354af3 | |
| parent | c96807abeade37994e1105bbea59e79c3d699114 (diff) | |
pinctrl: Fix two deadlocks
commit db93facfb0ef542aa5d8079e47580b3e669a4d82 upstream.
This patch is to fix two deadlock cases.
Deadlock 1:
CPU #1
pinctrl_register-> pinctrl_get ->
create_pinctrl
(Holding lock pinctrl_maps_mutex)
-> get_pinctrl_dev_from_devname
(Trying to acquire lock pinctrldev_list_mutex)
CPU #0
pinctrl_unregister
(Holding lock pinctrldev_list_mutex)
-> pinctrl_put ->> pinctrl_free ->
pinctrl_dt_free_maps -> pinctrl_unregister_map
(Trying to acquire lock pinctrl_maps_mutex)
Simply to say
CPU#1 is holding lock A and trying to acquire lock B,
CPU#0 is holding lock B and trying to acquire lock A.
Deadlock 2:
CPU #3
pinctrl_register-> pinctrl_get ->
create_pinctrl
(Holding lock pinctrl_maps_mutex)
-> get_pinctrl_dev_from_devname
(Trying to acquire lock pinctrldev_list_mutex)
CPU #2
pinctrl_unregister
(Holding lock pctldev->mutex)
-> pinctrl_put ->> pinctrl_free ->
pinctrl_dt_free_maps -> pinctrl_unregister_map
(Trying to acquire lock pinctrl_maps_mutex)
CPU #0
tegra_gpio_request
(Holding lock pinctrldev_list_mutex)
-> pinctrl_get_device_gpio_range
(Trying to acquire lock pctldev->mutex)
Simply to say
CPU#3 is holding lock A and trying to acquire lock D,
CPU#2 is holding lock B and trying to acquire lock A,
CPU#0 is holding lock D and trying to acquire lock B.
Signed-off-by: Jim Lin <jilin@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
| -rw-r--r-- | drivers/pinctrl/core.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c index a1ffae4c3770..260a2551d612 100644 --- a/drivers/pinctrl/core.c +++ b/drivers/pinctrl/core.c @@ -1796,14 +1796,15 @@ void pinctrl_unregister(struct pinctrl_dev *pctldev) if (pctldev == NULL) return; - mutex_lock(&pinctrldev_list_mutex); mutex_lock(&pctldev->mutex); - pinctrl_remove_device_debugfs(pctldev); + mutex_unlock(&pctldev->mutex); if (!IS_ERR(pctldev->p)) pinctrl_put(pctldev->p); + mutex_lock(&pinctrldev_list_mutex); + mutex_lock(&pctldev->mutex); /* TODO: check that no pinmuxes are still active? */ list_del(&pctldev->node); /* Destroy descriptor tree */ |