Bug 215000

Summary: webcamd panic
Product: Base System Reporter: Anton Shterenlikht <as>
Component: kernAssignee: freebsd-bugs (Nobody) <bugs>
Status: Closed FIXED    
Severity: Affects Only Me CC: hselasky, w.schwarzenfeld
Priority: ---    
Version: 11.0-STABLE   
Hardware: amd64   
OS: Any   
Attachments:
Description Flags
core.txt none

Description Anton Shterenlikht 2016-12-02 12:19:54 UTC 
Created attachment 177600 [details]
core.txt

FreeBSD 11.0-RELEASE-p2 #0: Mon Oct 24 06:55:27 UTC 2016
    root@amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC amd64

# cat /boot/loader.conf 
if_iwm_load="YES"
iwm3160fw_load="YES"
iwm7260fw_load="YES"
iwm7265fw_load="YES"
linux_load="YES"
cuse4bsd_load="YES"

Panics every time when webcamd_enable="YES" is added to
rc.conf. If webcamd is started manually, panic does not happen
immediately, and for a while the camera works, checked with pvcview.

See core.txt.7 attached.

Briefly:

Fatal trap 12: page fault while in kernel mode
cpuid = 2; apic id = 02
fault virtual address   = 0x100000019
fault code              = supervisor read data, page not present
instruction pointer     = 0x20:0xffffffff80b4392e
stack pointer           = 0x28:0xfffffe0234b714f0
frame pointer           = 0x28:0xfffffe0234b71540
code segment            = base rx0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 378 (webcamd)
trap number             = 12
panic: page fault
cpuid = 2
KDB: stack backtrace:
#0 0xffffffff80b24077 at kdb_backtrace+0x67
#1 0xffffffff80ad93e2 at vpanic+0x182
#2 0xffffffff80ad9253 at panic+0x43
#3 0xffffffff80fa0d51 at trap_fatal+0x351
#4 0xffffffff80fa0f43 at trap_pfault+0x1e3
#5 0xffffffff80fa04ec at trap+0x26c
#6 0xffffffff80f84141 at calltrap+0x8
#7 0xffffffff82581318 at cuse_server_close+0x178
#8 0xffffffff80985a35 at devfs_close+0x5e5
#9 0xffffffff8110ade9 at VOP_CLOSE_APV+0x89
#10 0xffffffff80bbdcce at vn_close+0x13e
#11 0xffffffff80bbc77a at vn_closefile+0x4a
#12 0xffffffff8098665c at devfs_close_f+0x2c
#13 0xffffffff80a735ca at _fdrop+0x1a
#14 0xffffffff80a770a4 at closef+0x2d4
#15 0xffffffff80a76b3d at fdescfree_fds+0x7d
#16 0xffffffff80a766f2 at fdescfree+0x6a2
#17 0xffffffff80a8855a at exit1+0x73a
Comment 1 Anton Shterenlikht 2016-12-07 10:28:33 UTC 
Suggested by scf@ in a private mail:

"I do suspect it is the specific cuse module you are loading.  It is possible that you are loading a module compiled for 10 when you are running 11.  Regardless, you should not be loading cuse4bsd any longer.  cuse(4) is part of FreeBSD 11 now. cuse_load="YES" is what you want."

Indeed changing to
cuse_load="YES"

fixed to the problem.

I think this PR can be closed.

However, the webcamd man page needs updating
because it still points to cuse4bsd:

WEBCAMD(8)              FreeBSD System Manager's Manual             WEBCAMD(8)

     webcamd requires the cuse4bsd(3) kernel module. To load the driver as a
     module at boot time, place the following line in loader.conf(5):

            cuse4bsd_load="YES"
Comment 2 Walter Schwarzenfeld 2018-01-13 22:18:18 UTC 
Is this still relevant?