kernel panic: This is bad! (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: bf9a9ba0d6af Add panic_hwtf() for kernel faults
git tree: https://github.com/akaros/akaros.git/master
console output: https://syzkaller.appspot.com/x/log.txt?x=10344d1c400000
kernel config: https://syzkaller.appspot.com/x/.config?x=efef8cf2939304d3
dashboard link: https://syzkaller.appspot.com/bug?extid=3299ff3288318dbc1a7a
compiler:

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+3299ff...@syzkaller.appspotmail.com

BIT16SZ 2, GBIT16(buf) 0 kernel panic at kern/arch/x86/trap.c:537, from
core 2: This is bad!
Double fault! Check the kernel stack pointer; you likely ran off the end
of the stack.
HW TRAP frame at 0xfffffff00001df40 on core 2
rax 0x000000000000003d
rbx 0xffffffffc8667ec0
rcx 0xffffffffc8667ec8
rdx 0x00000022841efc69
rbp 0xfffffff0000d6fd8
rsi 0x0000000000000003
rdi 0xffffffffc8667ec0
r8 0x0000000000000000
r9 0xffffffffc8667fb8
r10 0x0000000000000078
r11 0xffffffffc8667f78
r12 0xffff800002174020
r13 0x0000000000000002
r14 0x0000000000000000
r15 0x0000000000000002
trap 0x00000008 Double Fault
gsbs 0xffffffffc8667ec0
fsbs 0x0000000000000000
err 0x--------00000000
rip 0xffffffffc209f611
cs 0x------------0008
flag 0x0000000000010246
rsp 0xfffffff0000d6fd8
ss 0x------------0010
Backtrace of kernel context on Core 2:
#01 [<0xffffffffc209f611>] in cpu_halt at arch/x86/idle.c:20
#02 [<0xffffffffc2054696>] in __smp_idle at src/smp.c:84
kernel panic at kern/arch/x86/trap.c:537, from core 3: Double fault! Check
the kernel stack pointer; you likely ran off the end of the stack.
HW TRAP frame at 0xfffffff000026f40 on core 3
rax 0x0000000000000003
rbx 0x415d415c415b421a
rcx 0x0000000000000003
rdx 0x0000000000000000
rbp 0xfffffff0000beef8
rsi 0xffff80000d429100
rdi 0xffffffffc20ad035
r8 0x000030000003cee8
r9 0x0000000000000020
r10 0xffff8000000b8f00
r11 0x0000000000000000
r12 0xffff800002174f40
r13 0xffffffffc20ad04d
r14 0xffff80000d429100
r15 0xffffffffc20ad035
trap 0x00000008 Double Fault
gsbs 0xffffffffc8668140
fsbs 0x0000000000000000
err 0x--------00000000
rip 0xffffffffc2052d27
cs 0x------------0008
flag 0x0000000000010086
rsp 0xfffffff0000beec8
ss 0x------------0010
Backtrace of kernel context on Core 3:
#01 [<0xffffffffc2052d27>] in kmem_cache_free at src/slab.c:637
#02 [<0xffffffffc205a73d>] in process_routine_kmsg at src/trap.c:228
#03 [<0xffffffffc204d303>] in proc_restartcore at src/process.c:798
#04 [<0xffffffffc20ab2a0>] in sysenter_callwrapper at arch/x86/trap.c:853


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[Barret Rhoden]

On 2018-07-18 at 11:11 syzbot

#syz invalid