panic in sys_fstatat (?)

[Eric van Gyzen]

On 02/02/2015 12:59, Steve Kargl wrote:
> FreeBSD troutmask.apl.washington.edu 11.0-CURRENT FreeBSD 11.0-CURRENT
> #0 r278102M: Mon Feb  2 09:15:48 PST 2015
> kargl at troutmask.apl.washington.edu:/data/obj/usr/src/sys/SPEW  amd64
>
> Fatal trap 9: general protection fault while in kernel mode
> cpuid = 2; apic id = 12
> instruction pointer	= 0x20:0xffffffff80754567
> stack pointer	        = 0x28:0xfffffe0469290560
> frame pointer	        = 0x28:0xfffffe04692905a0
> 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		= 62150 (rm)
> trap number		= 9
> panic: general protection fault
> cpuid = 2
> KDB: stack backtrace:
> db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe0469290220
> panic() at panic+0x1c1/frame 0xfffffe04692902e0
> trap_fatal() at trap_fatal+0x380/frame 0xfffffe0469290340
> trap() at trap+0x6d1/frame 0xfffffe04692904a0
> calltrap() at calltrap+0x8/frame 0xfffffe04692904a0
> --- trap 0x9, rip = 0xffffffff80754567, rsp = 0xfffffe0469290560, rbp = 0xfffffe04692905a0 ---
> ufs_getattr() at ufs_getattr+0x87/frame 0xfffffe04692905a0
> VOP_GETATTR_APV() at VOP_GETATTR_APV+0x7a/frame 0xfffffe04692905d0
> vn_stat() at vn_stat+0x62/frame 0xfffffe04692906c0
> kern_statat() at kern_statat+0xe4/frame 0xfffffe0469290880
> sys_fstatat() at sys_fstatat+0x2c/frame 0xfffffe0469290920
> amd64_syscall() at amd64_syscall+0x289/frame 0xfffffe0469290a30
> Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe0469290a30
> --- syscall (493, FreeBSD ELF64, sys_fstatat), rip = 0x2008b3e9a, rsp = 0x7fffffffdc88, rbp = 0x7fffffffdd30 ---
> Uptime: 10m14s
>
>
> (kgdb) #0  doadump (textdump=Unhandled dwarf expression opcode 0x93
> ) at pcpu.h:219
> #1  0xffffffff80559f47 in kern_reboot (howto=260)
>     at /usr/src/sys/kern/kern_shutdown.c:448
> #2  0xffffffff8055a3b0 in panic (fmt=<value optimized out>)
>     at /usr/src/sys/kern/kern_shutdown.c:747
> #3  0xffffffff807a85c0 in trap_fatal (frame=<value optimized out>, 
>     eva=<value optimized out>) at /usr/src/sys/amd64/amd64/trap.c:861
> #4  0xffffffff807a8221 in trap (frame=<value optimized out>)
>     at /usr/src/sys/amd64/amd64/trap.c:201
> #5  0xffffffff8078d843 in calltrap ()
>     at /usr/src/sys/amd64/amd64/exception.S:235
> #6  0xffffffff80754567 in ufs_getattr (ap=<value optimized out>)
>     at /usr/src/sys/ufs/ufs/ufs_vnops.c:463
> #7  0xffffffff808074fa in VOP_GETATTR_APV (vop=<value optimized out>, 
>     a=<value optimized out>) at vnode_if.c:731
> #8  0xffffffff80607e62 in vn_stat (vp=0xfffff80088086000, 
>     sb=0xfffffe0469290710, active_cred=0xfffff8000b07d800, file_cred=0x1, 
>     td=0xfffff801b5063000) at vnode_if.h:309
> #9  0xffffffff806017e4 in kern_statat (td=0xfffff801b5063000, 
>     flag=<value optimized out>, fd=<value optimized out>, 
>     path=<value optimized out>, pathseg=UIO_USERSPACE, 
>     sbp=0xfffffe04692908a0, hook=0xfefff80034ba0700)
>     at /usr/src/sys/kern/vfs_syscalls.c:2241
> #10 0xffffffff80601acc in sys_fstatat (td=0xfffff802dbc03dc8, 
>     uap=0xfffffe04692909c0) at /usr/src/sys/kern/vfs_syscalls.c:2215
> #11 0xffffffff807a8db9 in amd64_syscall (td=0xfffff801b5063000, traced=0)
>     at subr_syscall.c:133
> #12 0xffffffff8078db2b in Xfast_syscall ()
>     at /usr/src/sys/amd64/amd64/exception.S:395

I probably can't help debug this, but someone who _can_ will likely ask
for this from kgdb:

f 6
x/i $rip
info reg

Eric