]> git.ipfire.org Git - thirdparty/kernel/stable.git/commit
usb: dwc3: Fix race condition between concurrent dwc3_remove_requests() call paths
authorManish Nagar <manish.nagar@oss.qualcomm.com>
Thu, 20 Nov 2025 07:44:35 +0000 (13:14 +0530)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 6 Dec 2025 21:25:01 +0000 (06:25 +0900)
commit7cfb62888eba292fa35cd9ddbd28ce595f60e139
tree00672faa5fd8defdaff8dda371e264bc48724cbc
parent61fcb9833071f36e4229b09f3549dc6cbab02c10
usb: dwc3: Fix race condition between concurrent dwc3_remove_requests() call paths

commit e4037689a366743c4233966f0e74bc455820d316 upstream.

This patch addresses a race condition caused by unsynchronized
execution of multiple call paths invoking `dwc3_remove_requests()`,
leading to premature freeing of USB requests and subsequent crashes.

Three distinct execution paths interact with `dwc3_remove_requests()`:
Path 1:
Triggered via `dwc3_gadget_reset_interrupt()` during USB reset
handling. The call stack includes:
- `dwc3_ep0_reset_state()`
- `dwc3_ep0_stall_and_restart()`
- `dwc3_ep0_out_start()`
- `dwc3_remove_requests()`
- `dwc3_gadget_del_and_unmap_request()`

Path 2:
Also initiated from `dwc3_gadget_reset_interrupt()`, but through
`dwc3_stop_active_transfers()`. The call stack includes:
- `dwc3_stop_active_transfers()`
- `dwc3_remove_requests()`
- `dwc3_gadget_del_and_unmap_request()`

Path 3:
Occurs independently during `adb root` execution, which triggers
USB function unbind and bind operations. The sequence includes:
- `gserial_disconnect()`
- `usb_ep_disable()`
- `dwc3_gadget_ep_disable()`
- `dwc3_remove_requests()` with `-ESHUTDOWN` status

Path 3 operates asynchronously and lacks synchronization with Paths
1 and 2. When Path 3 completes, it disables endpoints and frees 'out'
requests. If Paths 1 or 2 are still processing these requests,
accessing freed memory leads to a crash due to use-after-free conditions.

To fix this added check for request completion and skip processing
if already completed and added the request status for ep0 while queue.

Fixes: 72246da40f37 ("usb: Introduce DesignWare USB3 DRD Driver")
Cc: stable <stable@kernel.org>
Suggested-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Manish Nagar <manish.nagar@oss.qualcomm.com>
Link: https://patch.msgid.link/20251120074435.1983091-1-manish.nagar@oss.qualcomm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/dwc3/ep0.c
drivers/usb/dwc3/gadget.c