Panic in stable/11 (amd64) @r303903: page fault while in kernel mode

Wed Aug 10 16:55:01 UTC 2016

Happened after a few iterations of {"pkill dhclient" followed by
"dhclient wlan0"}.

Gory details (both "normal" and gzipped, and including the crash
dump and crashinfo) are in
<http://www.catwhisker.org/~david/FreeBSD/stable_11/2016.08.10/>.

Summary:
Wed Aug 10 15:56:26 UTC 2016

FreeBSD  11.0-BETA4 FreeBSD 11.0-BETA4 #69  r303902M/303903:1100120: Wed Aug 10 04:00:09 PDT 2016     root at g1-252.catwhisker.org:/common/S3/obj/usr/src/sys/CANARY  amd64

panic: page fault

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Unread portion of the kernel message buffer:

Fatal trap 12: page fault while in kernel mode
cpuid = 7; apic id = 07
fault virtual address	= 0x0
fault code		= supervisor read data, page not present
instruction pointer	= 0x20:0xffffffff80bdaaa1
stack pointer	        = 0x28:0xfffffe060bc956e0
frame pointer	        = 0x28:0xfffffe060bc957b0
code segment		= base 0x0, limit 0xfffff, type 0x1b
			= DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags	= interrupt enabled, resume, IOPL = 0
current process		= 20685 (wpa_supplicant)
trap number		= 12
panic: page fault
cpuid = 7
KDB: stack backtrace:
#0 0xffffffff80add787 at kdb_backtrace+0x67
#1 0xffffffff80a950e2 at vpanic+0x182
#2 0xffffffff80a94f53 at panic+0x43
#3 0xffffffff80eead51 at trap_fatal+0x351
#4 0xffffffff80eeaf43 at trap_pfault+0x1e3
#5 0xffffffff80eea4ec at trap+0x26c
#6 0xffffffff80ece0d1 at calltrap+0x8
#7 0xffffffff80b9811c at ifioctl+0x133c
#8 0xffffffff80afc914 at kern_ioctl+0x2d4
#9 0xffffffff80afc5d1 at sys_ioctl+0x171
#10 0xffffffff80eeb6c9 at amd64_syscall+0x4e9
#11 0xffffffff80ece3bb at Xfast_syscall+0xfb
Uptime: 3h0m4s
...
Reading symbols from /boot/kernel/linux64.ko...Reading symbols from /usr/lib/debug//boot/kernel/linux64.ko.debug...done.
done.
Loaded symbols for /boot/kernel/linux64.ko
#0  doadump (textdump=<value optimized out>) at pcpu.h:221
221	pcpu.h: No such file or directory.
	in pcpu.h
(kgdb) #0  doadump (textdump=<value optimized out>) at pcpu.h:221
#1  0xffffffff80a94b69 in kern_reboot (howto=260)
    at /usr/src/sys/kern/kern_shutdown.c:366
#2  0xffffffff80a9511b in vpanic (fmt=<value optimized out>, 
    ap=<value optimized out>) at /usr/src/sys/kern/kern_shutdown.c:759
#3  0xffffffff80a94f53 in panic (fmt=0x0)
    at /usr/src/sys/kern/kern_shutdown.c:690
#4  0xffffffff80eead51 in trap_fatal (frame=0xfffffe060bc95630, eva=0)
    at /usr/src/sys/amd64/amd64/trap.c:841
#5  0xffffffff80eeaf43 in trap_pfault (frame=0xfffffe060bc95630, usermode=0)
    at /usr/src/sys/amd64/amd64/trap.c:691
#6  0xffffffff80eea4ec in trap (frame=0xfffffe060bc95630)
    at /usr/src/sys/amd64/amd64/trap.c:442
#7  0xffffffff80ece0d1 in calltrap ()
    at /usr/src/sys/amd64/amd64/exception.S:236
#8  0xffffffff80bdaaa1 in ieee80211_ioctl (ifp=0xfffff80007991800, 
    cmd=<value optimized out>, data=<value optimized out>)
    at /usr/src/sys/net80211/ieee80211_ioctl.c:3398
#9  0xffffffff80b9811c in ifioctl (so=<value optimized out>, 
    cmd=<value optimized out>, data=<value optimized out>, 
    td=<value optimized out>) at /usr/src/sys/net/if.c:2447
#10 0xffffffff80afc914 in kern_ioctl (td=<value optimized out>, 
    fd=<value optimized out>, com=2149607696, data=0xfffffe060bc958e0 "wlan0")
    at file.h:327
#11 0xffffffff80afc5d1 in sys_ioctl (td=<value optimized out>, 
    uap=0xfffffe060bc95a40) at /usr/src/sys/kern/sys_generic.c:743
#12 0xffffffff80eeb6c9 in amd64_syscall (td=<value optimized out>, 
    traced=<value optimized out>) at subr_syscall.c:135
#13 0xffffffff80ece3bb in Xfast_syscall ()
    at /usr/src/sys/amd64/amd64/exception.S:396
#14 0x00000008015c448a in ?? ()
Previous frame inner to this frame (corrupt stack?)
Current language:  auto; currently minimal
(kgdb) 

This was on my laptop, which I'm actively using at work as I type
-- though it's now connected via wired NIC (em0).  I had experienced
no trouble with wlan0 at home (before coming in to work) or on the
bus (en route to work).  (I didn't attempt it while cycling to the
bus stop. :-})

Also, I had no issues running stable/11 (amd64) @303870 -- either
at home or at work -- yesterday.  On the other hand, this is (so
far) a one-off, so alleging a "pattern" at this point is not something
I'm willing to do.

Peace,
david
-- 
David H. Wolfskill				david at catwhisker.org
Those who would murder in the name of God or prophet are blasphemous cowards.

See http://www.catwhisker.org/~david/publickey.gpg for my public key.
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