summaryrefslogtreecommitdiff
path: root/drivers/pinctrl
diff options
context:
space:
mode:
authorJim Lin <jilin@nvidia.com>2015-01-08 20:25:05 +0800
committerLinus Walleij <linus.walleij@linaro.org>2015-01-14 14:20:33 +0100
commitdb93facfb0ef542aa5d8079e47580b3e669a4d82 (patch)
treedcd2c575ba728082ad76d209aac3fe4a36f7e266 /drivers/pinctrl
parent53b1bfc76df23230bbe32fd5879ff4927f04c53a (diff)
downloadkernel-db93facfb0ef542aa5d8079e47580b3e669a4d82.tar.gz
pinctrl: Fix two deadlocks
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. Cc: Stable <stable@vger.kernel.org> Signed-off-by: Jim Lin <jilin@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/pinctrl')
-rw-r--r--drivers/pinctrl/core.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index e4f65510c87e..89dca77ca038 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -1801,14 +1801,15 @@ 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 */