In the Linux kernel, the following vulnerability has been resolved:

usb: dwc3: Remove WARN_ON for device endpoint command timeouts

This commit addresses a rarely observed endpoint command timeout which causes kernel panic due to warn when panic_on_warn is enabled and unnecessary call trace prints when panic_on_warn is disabled. It is seen during fast software-controlled connect/disconnect testcases. The following is one such endpoint command timeout that we observed:

1. Connect

->dwc3_thread_interrupt ->dwc3_ep0_interrupt ->configfs_composite_setup ->composite_setup ->usb_ep_queue ->dwc3_gadget_ep0_queue ->__dwc3_gadget_ep0_queue ->__dwc3_ep0_do_control_data ->dwc3_send_gadget_ep_cmd

2. Disconnect

->dwc3_thread_interrupt ->dwc3_gadget_disconnect_interrupt ->dwc3_ep0_reset_state ->dwc3_ep0_end_control_data ->dwc3_send_gadget_ep_cmd

In the issue scenario, in Exynos platforms, we observed that control transfers for the previous connect have not yet been completed and end transfer command sent as a part of the disconnect sequence and processing of USB_ENDPOINT_HALT feature request from the host timeout. This maybe an expected scenario since the controller is processing EP commands sent as a part of the previous connect. It maybe better to remove WARN_ON in all places where device endpoint commands are sent to avoid unnecessary kernel panic due to warn.

Affected Software

References

• https://git.kernel.org/stable/c/45eae113dccaf8e502090ecf5b3d9e9b805add6f
• https://git.kernel.org/stable/c/5a1a847d841505dba2bd85602daf5c218e1d85b8
• https://git.kernel.org/stable/c/84c95dbf5bece56086cdb65a64162af35158bdd9
• https://git.kernel.org/stable/c/db27482b9db340402e05d4e9b75352bbaca51af2
• https://git.kernel.org/stable/c/dfe40159eec6ca63b40133bfa783eee2e3ed829f
• https://git.kernel.org/stable/c/f49697dfba2915a9ff36f94604eb76fa61413929