Bug 212332

I've had multiple panics recently with 11, where I did get a kernel dump stored, but where kgdb complains about a corrupt stack:

kgdb /boot/kernel/kernel /var/crash/vmcore.0
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This GDB was configured as "amd64-marcel-freebsd"...(no debugging symbols found)...
Attempt to extract a component of a value that is not a structure pointer.
Attempt to extract a component of a value that is not a structure pointer.
#0  0xffffffff80ad6e1f in doadump ()
(kgdb) bt
#0  0xffffffff80ad6e1f in doadump ()
#1  0xffffffff80ad6e48 in doadump ()
#2  0xfffffe0841422490 in ?? ()
#3  0xffffffff80ad6ab9 in kern_reboot ()
Previous frame identical to this frame (corrupt stack?)


The dmesg output is more helpful:
Sleeping thread (tid 101191, pid 1063) owns a non-sleepable lock
KDB: stack backtrace of thread 101191:
#0 0xffffffff80ae23a2 at mi_switch+0xd2
#1 0xffffffff80b301f7 at sleepq_catch_signals+0xb7
#2 0xffffffff80b308b4 at sleepq_timedwait_sig+0x14
#3 0xffffffff80a645b4 at _cv_timedwait_sig_sbt+0x1c4
#4 0xffffffff80b40c67 at seltdwait+0xc7
#5 0xffffffff80b40759 at kern_select+0x979
#6 0xffffffff80b40b94 at sys_select+0x54
#7 0xffffffff80fa06b8 at amd64_syscall+0x4d8
#8 0xffffffff80f82c9b at Xfast_syscall+0xfb
panic: sleeping thread
cpuid = 11
KDB: stack backtrace:
#0 0xffffffff80b220c7 at kdb_backtrace+0x67
#1 0xffffffff80ad7032 at vpanic+0x182
#2 0xffffffff80ad6ea3 at panic+0x43
#3 0xffffffff80b37ac9 at propagate_priority+0x299
#4 0xffffffff80b385cf at turnstile_wait+0x3ef
#5 0xffffffff80ab24bd at __mtx_lock_sleep+0x13d
#6 0xffffffff80b41a92 at doselwakeup+0x162
#7 0xffffffff80b6cd6e at sowakeup+0x1e
#8 0xffffffff80b7f18a at uipc_send+0xe3a
#9 0xffffffff80b71be7 at sosend_generic+0x5e7
#10 0xffffffff80b49b59 at soo_write+0x49
#11 0xffffffff80b3f307 at dofilewrite+0x87
#12 0xffffffff80b3efe8 at kern_writev+0x68
#13 0xffffffff80b3f256 at sys_writev+0x36
#14 0xffffffff80fa06b8 at amd64_syscall+0x4d8
#15 0xffffffff80f82c9b at Xfast_syscall+0xfb

This system is current to 11-stable as of today:
At revision 305285.

System is used as Xorg workstation, using Linux emulation (specifically skype client with /proc and /sys filesystems). 
If I can extract further data from the kernel dump than what kgdb reports, please let me know. Using the ports kgdb 
doesn't yield more details, either:

kgdb7111 /boot/kernel/kernel /var/crash/vmcore.0 
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Reading symbols from /boot/kernel/kernel...(no debugging symbols found)...done.
Reading symbols from /boot/kernel/linprocfs.ko...(no debugging symbols found)...done.
Reading symbols from /boot/kernel/linux_common.ko...(no debugging symbols found)...done.
Reading symbols from /boot/kernel/linsysfs.ko...(no debugging symbols found)...done.
Reading symbols from /boot/kernel/zfs.ko...(no debugging symbols found)...done.
Reading symbols from /boot/kernel/opensolaris.ko...(no debugging symbols found)...done.
Reading symbols from /boot/kernel/linux.ko...(no debugging symbols found)...done.
Reading symbols from /boot/kernel/coretemp.ko...(no debugging symbols found)...done.
Reading symbols from /boot/modules/nvidia.ko...(no debugging symbols found)...done.
Reading symbols from /boot/kernel/sem.ko...(no debugging symbols found)...done.
Reading symbols from /boot/kernel/tmpfs.ko...(no debugging symbols found)...done.
Reading symbols from /boot/kernel/ums.ko...(no debugging symbols found)...done.
Reading symbols from /boot/kernel/uhid.ko...(no debugging symbols found)...done.
Reading symbols from /boot/modules/vboxdrv.ko...(no debugging symbols found)...done.
Reading symbols from /boot/modules/vboxnetflt.ko...(no debugging symbols found)...done.
Reading symbols from /boot/kernel/netgraph.ko...(no debugging symbols found)...done.
Reading symbols from /boot/kernel/ng_ether.ko...(no debugging symbols found)...done.
Reading symbols from /boot/modules/vboxnetadp.ko...(no debugging symbols found)...done.
Reading symbols from /boot/kernel/linux64.ko...(no debugging symbols found)...done.
0xffffffff80ad6e1f in doadump ()
(kgdb) bt
#0  0xffffffff80ad6e1f in doadump ()
#1  0xffffffff80ad6e48 in doadump ()
#2  0xfffffe0841422490 in ?? ()
#3  0xffffffff80ad6ab9 in kern_reboot ()
Backtrace stopped: frame did not save the PC



Kind regards,
Markus