Kernel built with extcon and charger-manager. After connecting the USB cable sleeping function was called from atomic context: [ 63.328648] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:586 [ 63.331449] in_atomic(): 1, irqs_disabled(): 128, pid: 906, name: kworker/1:2 [ 63.338562] INFO: lockdep is turned off. [ 63.342468] irq event stamp: 0 [ 63.345507] hardirqs last enabled at (0): [< (null)>] (null) [ 63.351495] hardirqs last disabled at (0): [<c00246c8>] copy_process.part.46+0x4a0/0x1684 [ 63.359654] softirqs last enabled at (0): [<c00246c8>] copy_process.part.46+0x4a0/0x1684 [ 63.367813] softirqs last disabled at (0): [< (null)>] (null) [ 63.373802] Preemption disabled at:[< (null)>] (null) [ 63.379097] [ 63.380581] CPU: 1 PID: 906 Comm: kworker/1:2 Not tainted 3.16.2-00822-g691a2ac4e574 #954 [ 63.388743] Workqueue: events max14577_muic_irq_work [ 63.393707] [<c00167a4>] (unwind_backtrace) from [<c0012c08>] (show_stack+0x10/0x14) [ 63.401422] [<c0012c08>] (show_stack) from [<c06232ec>] (dump_stack+0x70/0xbc) [ 63.408625] [<c06232ec>] (dump_stack) from [<c0629d0c>] (mutex_lock_nested+0x24/0x410) [ 63.416525] [<c0629d0c>] (mutex_lock_nested) from [<c0354474>] (regmap_read+0x30/0x60) [ 63.424424] [<c0354474>] (regmap_read) from [<c0406b84>] (max14577_charger_get_property+0x1e4/0x250) [ 63.433535] [<c0406b84>] (max14577_charger_get_property) from [<c0403834>] (is_ext_pwr_online+0x30/0x6c) [ 63.442994] [<c0403834>] (is_ext_pwr_online) from [<c0404a54>] (charger_extcon_notifier+0x40/0x70) [ 63.451934] [<c0404a54>] (charger_extcon_notifier) from [<c044cbe4>] (_call_per_cable+0x40/0x4c) [ 63.460704] [<c044cbe4>] (_call_per_cable) from [<c0051560>] (notifier_call_chain+0x64/0x128) [ 63.469209] [<c0051560>] (notifier_call_chain) from [<c0051640>] (raw_notifier_call_chain+0x18/0x20) [ 63.478321] [<c0051640>] (raw_notifier_call_chain) from [<c044d0fc>] (extcon_update_state+0xa8/0x204) [ 63.487522] [<c044d0fc>] (extcon_update_state) from [<c044e5f8>] (max14577_muic_chg_handler+0xdc/0x180) [ 63.496897] [<c044e5f8>] (max14577_muic_chg_handler) from [<c044e924>] (max14577_muic_irq_work+0x7c/0xd8) [ 63.506445] [<c044e924>] (max14577_muic_irq_work) from [<c004480c>] (process_one_work+0x198/0x66c) [ 63.515385] [<c004480c>] (process_one_work) from [<c0044d4c>] (worker_thread+0x38/0x564) [ 63.523455] [<c0044d4c>] (worker_thread) from [<c004c4ec>] (kthread+0xcc/0xe8) [ 63.530661] [<c004c4ec>] (kthread) from [<c000f1f8>] (ret_from_fork+0x14/0x3c) [ 63.543926] charger_manager: Set current limit of CHARGER : 450000uA ~ 450000uA [ 63.548870] extcon-port jack: jack event CHGDET=usb [ 63.550592] extcon-port jack: jack event CHGDET=charger [ 64.188607] charger-manager charger-manager@0: Failed to get battery temperature [ 64.200684] charger-manager charger-manager@0: CHARGING
The first sleeping function is is_ext_pwr_online() (drivers/power/charger-manager.c). The atomic context initiating the flow is set up in extcon_update_state() (drivers/extcon/extcon-class.c). The extcon_update_state() uses spin locks which are not necessary because the function is not called from interrupt service routines. Instead, the extcon_update_state() is called from: 1. Threaded interrupt handlers. 2. Work queues. Replace the spin lock with mutex and update the documentation of this function. Signed-off-by: Krzysztof Kozlowski <[email protected]> --- drivers/extcon/extcon-class.c | 15 ++++++++------- include/linux/extcon.h | 3 ++- 2 files changed, 10 insertions(+), 8 deletions(-) diff --git a/drivers/extcon/extcon-class.c b/drivers/extcon/extcon-class.c index 4c2f2c543bb7..7485600baeff 100644 --- a/drivers/extcon/extcon-class.c +++ b/drivers/extcon/extcon-class.c @@ -201,6 +201,8 @@ static ssize_t cable_state_show(struct device *dev, * * Note that the notifier provides which bits are changed in the state * variable with the val parameter (second) to the callback. + * + * The function may sleep thus may not be called from atomic context. */ int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state) { @@ -210,16 +212,15 @@ int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state) char *envp[3]; int env_offset = 0; int length; - unsigned long flags; - spin_lock_irqsave(&edev->lock, flags); + mutex_lock(&edev->lock); if (edev->state != ((edev->state & ~mask) | (state & mask))) { u32 old_state = edev->state; if (check_mutually_exclusive(edev, (edev->state & ~mask) | (state & mask))) { - spin_unlock_irqrestore(&edev->lock, flags); + mutex_unlock(&edev->lock); return -EPERM; } @@ -248,20 +249,20 @@ int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state) } envp[env_offset] = NULL; /* Unlock early before uevent */ - spin_unlock_irqrestore(&edev->lock, flags); + mutex_unlock(&edev->lock); kobject_uevent_env(&edev->dev.kobj, KOBJ_CHANGE, envp); free_page((unsigned long)prop_buf); } else { /* Unlock early before uevent */ - spin_unlock_irqrestore(&edev->lock, flags); + mutex_unlock(&edev->lock); dev_err(&edev->dev, "out of memory in extcon_set_state\n"); kobject_uevent(&edev->dev.kobj, KOBJ_CHANGE); } } else { /* No changes */ - spin_unlock_irqrestore(&edev->lock, flags); + mutex_unlock(&edev->lock); } return 0; @@ -834,7 +835,7 @@ int extcon_dev_register(struct extcon_dev *edev) ret = class_compat_create_link(switch_class, &edev->dev, NULL); #endif /* CONFIG_ANDROID */ - spin_lock_init(&edev->lock); + mutex_init(&edev->lock); RAW_INIT_NOTIFIER_HEAD(&edev->nh); diff --git a/include/linux/extcon.h b/include/linux/extcon.h index 36f49c405dfb..166f42cecd5a 100644 --- a/include/linux/extcon.h +++ b/include/linux/extcon.h @@ -26,6 +26,7 @@ #include <linux/device.h> #include <linux/notifier.h> #include <linux/sysfs.h> +#include <linux/mutex.h> #define SUPPORTED_CABLE_MAX 32 #define CABLE_NAME_MAX 30 @@ -125,7 +126,7 @@ struct extcon_dev { struct raw_notifier_head nh; struct list_head entry; int max_supported; - spinlock_t lock; /* could be called by irq handler */ + struct mutex lock; u32 state; /* /sys/class/extcon/.../cable.n/... */ -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
