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ANDROID: usb: gadget: android_f_accessory: use spinlock instead of

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mutex lock

The configfs_composite_disconnect function was holding a spin lock, and
the android_acc_disconnect function was holding a mutex lock. As a
result of this, sleeping function called from invalid context error was
coming.

[  106.229993][  T987] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:289
[  106.231143][  T987] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 987, name: android.hardwar
[  106.232305][  T987] preempt_count: 1, expected: 0   //hold spin_lock_irqsave(&gi->spinlock, flags) and preempt_count will plus one
[  106.232899][  T987] RCU nest depth: 0, expected: 0
[  106.233505][  T987] Preemption disabled at:
[  106.233507][  T987] [<ffffffdaa1a288f0>] configfs_composite_disconnect+0x2c/0x6c
[  106.234055][  T987] CPU: 6 PID: 987 Comm: android.hardwar Tainted: G        W  OE      6.6.17-android15-1-ge8779207b2e9 #1
[  106.236422][  T987] Hardware name: MT6991(ENG) (DT)
[  106.236425][  T987] Call trace:
[  106.236426][  T987]  dump_backtrace+0xec/0x138
[  106.236434][  T987]  show_stack+0x18/0x24
[  106.236437][  T987]  dump_stack_lvl+0x50/0x6c
[  106.236449][  T987]  dump_stack+0x18/0x24
[  106.236452][  T987]  __might_resched+0x150/0x170
[  106.236458][  T987]  __might_sleep+0x48/0x7c
[  106.236460][  T987]  mutex_lock+0x24/0x74
[  106.236465][  T987]  android_acc_disconnect+0x1c/0xe0
[  106.236472][  T987]  __composite_disconnect+0x20/0x12c

Steps to reproduce the issue:
1. Connect the Android device via USB cable to the computer.
2. Open the USB Preference to change the USB function.
3. Select the MTP, PTP, or other USB function and switch it.
4. Kernel log will show this Warning log after switch USB function.

Test: manually tested the above steps, and successfully switch between
USB modes.
Bug: 322732675

Change-Id: I8131595b02ecb2631defcca4cdde456d83f76525
Signed-off-by: Ashish Kumar Gupta <kumarashishg@google.com>
This commit is contained in:
Ashish Kumar Gupta
2024-03-27 13:56:45 +00:00
committed by Neill Kapron
parent d718cad4b6
commit 79c4b2fb58
1 changed files with 22 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/usb/gadget/function/android_f_accessory.c
+22 -10
View File
@@ -262,7 +262,7 @@ static struct usb_gadget_strings *acc_strings[] = {
NULL,
};
static DEFINE_MUTEX(acc_dev_instance_lock);
static DEFINE_SPINLOCK(acc_dev_instance_lock);
static struct acc_dev *acc_dev_instance;
struct acc_instance {
@@ -272,10 +272,12 @@ struct acc_instance {
static struct acc_dev *get_acc_dev(void)
{
mutex_lock(&acc_dev_instance_lock);
unsigned long flags;
spin_lock_irqsave(&acc_dev_instance_lock, flags);
if (acc_dev_instance)
kref_get(&acc_dev_instance->kref);
mutex_unlock(&acc_dev_instance_lock);
spin_unlock_irqrestore(&acc_dev_instance_lock, flags);
return acc_dev_instance;
}
@@ -297,8 +299,17 @@ static void __acc_dev_instance_release(struct kref *kref)
static void put_acc_dev(struct acc_dev *dev)
{
kref_put_mutex(&acc_dev_instance->kref, __acc_dev_instance_release,
&acc_dev_instance_lock);
unsigned long flags;
/*
* This is not best engineering practice, and does cause coupling with
* kref internal structure. It might cause an issue if kref internal
* refcount structure is changed. We will remove this implementation
* in the next kernel version.
*/
if (refcount_dec_and_lock_irqsave(&acc_dev_instance->kref.refcount,
&acc_dev_instance_lock, &flags))
__acc_dev_instance_release(&acc_dev_instance->kref);
}
static inline struct acc_dev *func_to_dev(struct usb_function *f)
@@ -1243,15 +1254,16 @@ static int acc_init(void)
{
struct acc_dev *dev;
int ret;
unsigned long flags;
mutex_lock(&acc_dev_instance_lock);
spin_lock_irqsave(&acc_dev_instance_lock, flags);
if (acc_dev_instance) {
mutex_unlock(&acc_dev_instance_lock);
spin_unlock_irqrestore(&acc_dev_instance_lock, flags);
return -EBUSY;
}
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev) {
mutex_unlock(&acc_dev_instance_lock);
spin_unlock_irqrestore(&acc_dev_instance_lock, flags);
return -ENOMEM;
}
@@ -1273,12 +1285,12 @@ static int acc_init(void)
kref_init(&dev->kref);
acc_dev_instance = dev;
mutex_unlock(&acc_dev_instance_lock);
spin_unlock_irqrestore(&acc_dev_instance_lock, flags);
return 0;
err_free_dev:
kfree(dev);
mutex_unlock(&acc_dev_instance_lock);
spin_unlock_irqrestore(&acc_dev_instance_lock, flags);
pr_err("USB accessory gadget driver failed to initialize\n");
return ret;
}