Den tor. 25. feb. 2021 kl. 10.57 skrev Oliver Neukum <oneukum@xxxxxxxx>: > > Am Mittwoch, den 24.02.2021, 16:21 +0100 schrieb Bruno Thomsen: > > Hi, > > > No, this is not a regression from 5.10. It seems that many attempts to > > fix cdc-acm in the 5.x kernel series have failed to fix the root cause of > > these oops. I have not seen this on 4.14 and 4.19, but I have observed > > it on at least 5.3 and newer kernels in slight variations. > > I guess this is because cdc-acm is very common in the embedded > > ARM world and rarely used on servers or laptops. Combined with > > ARM devices still commonly use 4.x LTS kernels. Not sure if > > hardening options on the kernel has increased change of reproducing > > oops. > > OK, so this is not an additional problem. > According to your logs, an URB that should have been killed wasn't. Thanks for looking into this bug rapport. > > I am ready to test new patches and will continue to report oops > > Could you test the attached patches? Yes, I am already running tests on the patches. I have not seen any oops yet and it seems the USB cdc-acm driver is still working as intended. The only notable trace I have seen is this new error from the cdc-acm driver but everything kept on working. kernel: cdc_acm 1-1.1:1.7: acm_start_wb - usb_submit_urb(write bulk) failed: -19 Other then that I see this common error (should probably be a warning) during device enumeration: kernel: cdc_acm 1-1.2:1.0: failed to set dtr/rts I will post an update next week when the patches have survived some more runtime. /Bruno
