I had dig a bit future and setup a breakpoint at usbd_ref_decr.
It was called from uvideo_vs_start_bulk_thread, but still it crahses:
Breakpoint at usbd_ref_decr: endbr64
ddb{0}> bt
usbd_ref_decr(ffff800002177400) at usbd_ref_decr
uvideo_vs_start_bulk_thread(ffff80000021bf000) at
uvideo_vs_start_bulk_thread+0xc2
end trace frame: 0x0, count: -1
ddb{0}> c
uvm_fault(0xfffffffff027c89c8, 0x3f, 0, 2) -> e
kernel: page fault trap, code=2
Stopped at usbd_close_pipe+0x91: movq %rcx,0x40(%rax)
TID PID UID PRFLAGS PFLAGS CPU COMMAND
121458 83085 1000 0x100002 0 2 xconsole
210971 28938 0 0x14000 0x200 3 reaper
*468258 76766 0 0x14000 0x200 0K usbtask
512899 87028 0 0x14000 0x40000200 1 sensors
usbd_close_pipe(ffff800001e54000) at usbd_close_pipe+0x91
uvideo_close(ffff80000021bf000) at uvideo_close+0x57
videoclose(2c01,4,2000,ffff80003ab096e0) at videoclose+0x63
spec_close(ffff80003ab8f6c8) at spec_close+0x2b2
VOP_CLOSE(fffffdb23c0922c8,4,ffffffffffffff,ffff80003ab096e0) at
VOP_CLOSE+0x59
vclean(fffffdb23c0922c8,0,ffff80003ab096e0) at vclean+0x147
vgonel(fffffdb23c0922c8,ffff80003ab096e0) at vgonel+0x67
vop_generic_revoke(ffff80003ab8f7f8) at vop_generic_revoke+0x1a2
VOP_REVOKE(fffffdb23c0922c8,1) at VOP_REVOKE+0x3b
vdevgone(2c,1,1,4) at vdevgone+0xd5
videodetach(ffff800001fe4400,1) at videodetach+0x67
config_detach(ffff800001fe4400,1) at config_detach+0x166
uvideo_detach(ffff80000021bf000,1) at uvideo_detach+0x4a
config_detach(ffff80000021bf000,1) at config_detach+0x166
end trace frame: 0xffff80003ab8fa20, count: 0
https://www.openbsd.org/ddb.html describes the minimum info required in
bug
reports. Insufficient info makes it difficult to find and fix bugs.
ddb{0}>
and here the photo which I've captured with this stacktrace:
https://kirill.korins.ky/pub/openbsd-webcam-deattach-crash.jpg
--
wbr, Kirill
