50896c4103
The syzkaller USB fuzzer identified a failure mode in which dummy-hcd would never give back an unlinked URB. This causes usb_kill_urb() to hang, leading to WARNINGs and unkillable threads. In dummy-hcd, all URBs are given back by the dummy_timer() routine as it scans through the list of pending URBS. Failure to give back URBs can be caused by failure to start or early exit from the scanning loop. The code currently has two such pathways: One is triggered when an unsupported bus transfer speed is encountered, and the other by exhausting the simulated bandwidth for USB transfers during a frame. This patch removes those two paths, thereby allowing all unlinked URBs to be given back in a timely manner. It adds a check for the bus speed when the gadget first starts running, so that dummy_timer() will never thereafter encounter an unsupported speed. And it prevents the loop from exiting as soon as the total bandwidth has been used up (the scanning loop continues, giving back unlinked URBs as they are found, but not transferring any more data). Thanks to Andrey Konovalov for manually running the syzkaller fuzzer to help track down the source of the bug. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-and-tested-by: syzbot+d919b0f29d7b5a4994b9@syzkaller.appspotmail.com CC: <stable@vger.kernel.org> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com> |
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| .. | ||
| function | ||
| legacy | ||
| udc | ||
| Kconfig | ||
| Makefile | ||
| composite.c | ||
| config.c | ||
| configfs.c | ||
| configfs.h | ||
| epautoconf.c | ||
| functions.c | ||
| u_f.c | ||
| u_f.h | ||
| u_os_desc.h | ||
| usbstring.c | ||