[Deepin-Kernel-SIG] [FROMLIST] [linux 6.6-y] Bluetooth: btusb: Add NULL check for data in btusb_suspend

[opsiff]

When performing warm boot tests with an MT7920 device, we encounter NULL pointer dereferences with failure rate 5/30. The crash occurs during device suspend when btusb attempts to access data->hdev where data is NULL. This may happen due to a race condition between PM suspend and device disconnect. The root cause needs further investigation.

BUG: kernel NULL pointer dereference, address: 0000000000000000
Workqueue: pm pm_runtime_work
RIP: 0010:btusb_suspend+0x1d/0x1d0 [btusb]

Add a NULL check for data and return -ENODEV in this case to prevent the NULL pointer dereference. This indicates that the device is no longer available, which is appropriate when the driver's private data is missing.

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关键摘要:

• 在btusb_suspend函数中新增了对data指针的检查，确保在data为空时返回-ENODEV错误码。

是否建议立即修改:

• 否，因为提交的代码已经添加了对data指针的空指针检查，这是一个合理的改动，可以防止空指针解引用的问题。但是，需要确保这个改动不会引入新的问题，比如是否所有调用btusb_suspend的地方都已经处理了-ENODEV错误码的情况。

其他建议:

• 确保所有调用btusb_suspend的地方都已经处理了-ENODEV错误码，以避免潜在的运行时错误。
• 考虑添加注释说明为什么在data为空时返回-ENODEV，以便其他开发者理解这一逻辑。
• 如果data指针的空检查是必要的，建议在整个btusb.c文件中查找其他可能存在类似问题的代码，并进行相应的检查和修改。