panic on epair destroy in current as of r349853, jail related

Hi,

I updated from r347365 to r349853. Now I get a panic on epair destroy  
(one end needs to be in a jail, and inside the jail an IP address  
needs to be assigned to the epair. If no ifconfig is used inside the  
jail, there is no panic.

Another user reported something similar (but for him it was enough to  
list the interfaces inside the jail with ifconfig) in PR 234985:
     https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=234985

Backtrace (here I also renamed the interface before attaching it to  
the jail, as I detected the issue with interfaces which are renamed):
Fatal trap 9: general protection fault while in kernel mode
cpuid = 13; apic id = 33
instruction pointer     = 0x20:0xffffffff805f2045
stack pointer           = 0x28:0xfffffe0159822880
frame pointer           = 0x28:0xfffffe0159822880
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         = 43334 (ifconfig)
trap number             = 9
panic: general protection fault
cpuid = 13
time = 1562695289
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe0159822590
vpanic() at vpanic+0x19d/frame 0xfffffe01598225e0
panic() at panic+0x43/frame 0xfffffe0159822640
trap_fatal() at trap_fatal+0x39c/frame 0xfffffe01598226a0
trap() at trap+0x6c/frame 0xfffffe01598227b0
calltrap() at calltrap+0x8/frame 0xfffffe01598227b0
--- trap 0x9, rip = 0xffffffff805f2045, rsp = 0xfffffe0159822880, rbp  
= 0xfffffe0159822880 ---
strncmp() at strncmp+0x15/frame 0xfffffe0159822880
ifunit_ref() at ifunit_ref+0x51/frame 0xfffffe01598228c0
ifioctl() at ifioctl+0x508/frame 0xfffffe0159822990
kern_ioctl() at kern_ioctl+0x26d/frame 0xfffffe0159822a00
sys_ioctl() at sys_ioctl+0x15d/frame 0xfffffe0159822ad0
amd64_syscall() at amd64_syscall+0x23a/frame 0xfffffe0159822bf0
fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe0159822bf0
--- syscall (54, FreeBSD ELF64, sys_ioctl), rip = 0x8004690da, rsp =  
0x7fffffffe448, rbp = 0x7fffffffe4b0 ---
Uptime: 3h34m59s
Dumping 5294 out of 61352 MB:..1%..11%..21%..31%..41%..51%..61%..71%..81%..91%

__curthread () at /space/system/usr_src/sys/amd64/include/pcpu.h:246
246             __asm("movq %%gs:%P1,%0" : "=r" (td) : "n"  
(OFFSETOF_CURTHREAD));
(kgdb) #0  __curthread () at  
/space/system/usr_src/sys/amd64/include/pcpu.h:246
#1  doadump (textdump=1) at /space/system/usr_src/sys/kern/kern_shutdown.c:392
#2  0xffffffff8050cf70 in kern_reboot (howto=260)
     at /space/system/usr_src/sys/kern/kern_shutdown.c:479
#3  0xffffffff8050d3e9 in vpanic (fmt=<optimized out>, ap=<optimized out>)
     at /space/system/usr_src/sys/kern/kern_shutdown.c:905
#4  0xffffffff8050d123 in panic (fmt=<unavailable>)
     at /space/system/usr_src/sys/kern/kern_shutdown.c:832
#5  0xffffffff807e758c in trap_fatal (frame=0xfffffe01598227c0, eva=0)
     at /space/system/usr_src/sys/amd64/amd64/trap.c:943
#6  0xffffffff807e698c in trap (frame=0xfffffe01598227c0)
     at /space/system/usr_src/sys/amd64/amd64/trap.c:221
#7  <signal handler called>
#8  0xffffffff805f2045 in strncmp (s1=<optimized out>, s2=<optimized out>,
     n=<optimized out>) at /space/system/usr_src/sys/libkern/strncmp.c:44
#9  0xffffffff80605d31 in ifunit_ref (name=0xfffffe0159822a20 "panic_test1b")
     at /space/system/usr_src/sys/net/if.c:2434
#10 0xffffffff80607ef8 in ifioctl (so=0xfffff809a1afd368, cmd=3223349536,
     data=0xfffffe0159822a20 "panic_test1b", td=0xfffff8014c83e5a0)
     at /space/system/usr_src/sys/net/if.c:3093
#11 0xffffffff8057658d in fo_ioctl (fp=<optimized out>, com=3223349536,
     data=0xfffff800020e2180, active_cred=0x0, td=0xfffff8014c83e5a0)
     at /space/system/usr_src/sys/sys/file.h:333
#12 kern_ioctl (td=0xfffff8014c83e5a0, fd=3, com=3223349536,
     data=0xfffff800020e2180 "")
     at /space/system/usr_src/sys/kern/sys_generic.c:800
#13 0xffffffff805762ad in sys_ioctl (td=0xfffff8014c83e5a0,
     uap=0xfffff8014c83e968) at  
/space/system/usr_src/sys/kern/sys_generic.c:712
#14 0xffffffff807e801a in syscallenter (td=0xfffff8014c83e5a0)
     at /space/system/usr_src/sys/amd64/amd64/../../kern/subr_syscall.c:135
#15 amd64_syscall (td=0xfffff8014c83e5a0, traced=0)
     at /space/system/usr_src/sys/amd64/amd64/trap.c:1181
#16 <signal handler called>
#17 0x00000008004690da in ?? ()
Backtrace stopped: Cannot access memory at address 0x7fffffffe448

Bye,
Alexander.

-- 
http://www.Leidinger.net Alexander_at_Leidinger.net: PGP 0x8F31830F9F2772BF
http://www.FreeBSD.org    netchild_at_FreeBSD.org  : PGP 0x8F31830F9F2772BF