Re: usb stick removal panics

["Sepherosa Ziehau" <sepherosa@xxxxxxxxx>]

On 5/30/07, Simon 'corecode' Schubert <corecode@fs.ei.tum.de> wrote:
> hey,
>
> repeatable panic here when removing my usb stick (when I didn't load umass.ko before):

Since ugen(4) is not loaded at all, the USB device's structure is only
partially initialized, i.e. nameunit is not initialized at all.
Please test following patch:
http://leaf.dragonflybsd.org/~sephe/usb_no_ugen.diff

Best Regards,
sephe

> Unread portion of the kernel message buffer:
> uhub1: at uhub0 port 4 (addr 3) disconnected
> kernel trap 12 with interrupts disabled
>
>
> Fatal trap 12: page fault while in kernel mode
> fault virtual address   = 0xdeadc0de
> fault code              = supervisor read, page not present
> instruction pointer     = 0x8:0xc0264ce0
> stack pointer           = 0x10:0xd2465b20
> frame pointer           = 0x10:0xd2465b20
> code segment            = base 0x0, limit 0xfffff, type 0x1b
>                         = DPL 0, pres 1, def32 1, gran 1
> processor eflags        = resume, IOPL = 0
> current process         = Idle
> current thread          = pri 76 (CRIT)
>
> trap number             = 12
> panic: page fault
> [...]
> (kgdb) bt
> #0  dumpsys () at thread.h:83
> #1  0xc017c8a7 in boot (howto=256) at /usr/build/src/sys/kern/kern_shutdown.c:373
> #2  0xc017c9d1 in panic (fmt=Variable "fmt" is not available.
> ) at /usr/build/src/sys/kern/kern_shutdown.c:792
> #3  0xc029185a in trap_fatal (frame=0xd2465ad8, eva=Variable "eva" is not available.
> )
>     at /usr/build/src/sys/platform/pc32/i386/trap.c:1097
> #4  0xc02919ad in trap_pfault (frame=0xd2465ad8, usermode=0, eva=3735929054)
>     at /usr/build/src/sys/platform/pc32/i386/trap.c:998
> #5  0xc02922dc in trap (frame=0xd2465ad8) at /usr/build/src/sys/platform/pc32/i386/trap.c:681
> #6  0xc02830d6 in calltrap () at /usr/build/src/sys/platform/pc32/i386/exception.s:783
> #7  0xc0264ce0 in strlen (str=0xdeadc0de <Address 0xdeadc0de out of bounds>)
>     at /usr/build/src/sys/libkern/strlen.c:44
> #8  0xc0194fc8 in kvcprintf (fmt=0xc02c566d ": at %s", func=0xc01959de <kputchar>, arg=0xd2465c50,
>     radix=10, ap=0xd2465c78 "�u\036�) at /usr/build/src/sys/kern/subr_prf.c:655
> #9  0xc01959b0 in kprintf (fmt=0xc02c566b "%s: at %s") at /usr/build/src/sys/kern/subr_prf.c:304
> #10 0xc025c561 in usb_disconnect_port (up=0xd53d9c68, parent=0xd53d98d8)
>     at /usr/build/src/sys/bus/usb/usb_subr.c:1382
> #11 0xc025f3d2 in uhub_detach (self=0xd53d98d8) at /usr/build/src/sys/bus/usb/uhub.c:610
> #12 0xc018e850 in device_detach (dev=0xd53d98d8) at device_if.h:49
> #13 0xc018e943 in device_delete_child (dev=0xcfaea500, child=0xd53d98d8)
>     at /usr/build/src/sys/kern/subr_bus.c:600
> #14 0xc025c5b0 in usb_disconnect_port (up=0xd24a5c74, parent=0xcfaea500)
>     at /usr/build/src/sys/bus/usb/usb_subr.c:1387
> #15 0xc025f119 in uhub_explore (dev=0xcfa8a8b8) at /usr/build/src/sys/bus/usb/uhub.c:460
> #16 0xc025985f in usb_discover (v=Variable "v" is not available.
> ) at /usr/build/src/sys/bus/usb/usb.c:784
> #17 0xc0259bf6 in usb_event_thread (arg=0xc22491c0) at /usr/build/src/sys/bus/usb/usb.c:473
> #18 0xc017181a in suspend_kproc (td=Variable "td" is not available.
> ) at /usr/build/src/sys/kern/kern_kthread.c:158
>
> seems either some variable isn't being initialized correctly, or something is freed prematurely.  no time to investigate, though.
>
> The USB stick I'm using has an integrated USB hub (why is beyond my imagination).
>
> cheers
>   simon
>
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