KASAN: stack-out-of-bounds Read in unwind_next_frame

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 47350a9f ANDROID: x86_64_cuttlefish_defconfig: Enable lz4 ..
git tree: android-4.14
console output: https://syzkaller.appspot.com/x/log.txt?x=1265013e400000
kernel config: https://syzkaller.appspot.com/x/.config?x=10d236078f3378a3
dashboard link: https://syzkaller.appspot.com/bug?extid=a9b06fe7ffe73fed771b
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16f16f0e400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12e42951400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+a9b06f...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: stack-out-of-bounds in deref_stack_regs
arch/x86/kernel/unwind_orc.c:290 [inline]
BUG: KASAN: stack-out-of-bounds in unwind_next_frame+0x1595/0x1930
arch/x86/kernel/unwind_orc.c:420
Read of size 8 at addr ffff8801c690f6d0 by task syz-executor901/2295

CPU: 0 PID: 2295 Comm: syz-executor901 Not tainted 4.14.67+ #1
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0xb9/0x11b lib/dump_stack.c:53
print_address_description+0x60/0x22b mm/kasan/report.c:252
kasan_report_error mm/kasan/report.c:351 [inline]
kasan_report.cold.6+0x11b/0x2dd mm/kasan/report.c:409
deref_stack_regs arch/x86/kernel/unwind_orc.c:290 [inline]
unwind_next_frame+0x1595/0x1930 arch/x86/kernel/unwind_orc.c:420
perf_callchain_kernel+0x39c/0x540 arch/x86/events/core.c:2354
get_perf_callchain+0x2eb/0x760 kernel/events/callchain.c:217
perf_callchain+0x14a/0x190 kernel/events/callchain.c:190
perf_prepare_sample+0x704/0x13c0 kernel/events/core.c:6130
__perf_event_output kernel/events/core.c:6246 [inline]
perf_event_output_forward+0xeb/0x230 kernel/events/core.c:6264
__perf_event_overflow+0x116/0x320 kernel/events/core.c:7500
perf_swevent_overflow+0x166/0x1f0 kernel/events/core.c:7576
perf_swevent_event+0x112/0x270 kernel/events/core.c:7614
perf_tp_event+0x5e5/0x790 kernel/events/core.c:8038
perf_trace_run_bpf_submit+0x10f/0x170 kernel/events/core.c:8008
perf_trace_lock+0x2f6/0x4c0 include/trace/events/lock.h:39
trace_lock_release include/trace/events/lock.h:58 [inline]
lock_release+0x4dc/0x720 kernel/locking/lockdep.c:4009
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:158 [inline]
_raw_spin_unlock_irqrestore+0x1b/0x70 kernel/locking/spinlock.c:192
__debug_check_no_obj_freed lib/debugobjects.c:758 [inline]
debug_check_no_obj_freed+0x2b2/0x77c lib/debugobjects.c:774
slab_free_hook mm/slub.c:1382 [inline]
slab_free_freelist_hook mm/slub.c:1410 [inline]
slab_free mm/slub.c:2966 [inline]
kmem_cache_free+0x218/0x350 mm/slub.c:2988
kfree_skbmem+0x9e/0x100 net/core/skbuff.c:582
__kfree_skb net/core/skbuff.c:642 [inline]
kfree_skb+0xd0/0x340 net/core/skbuff.c:659
tun_queue_purge+0x108/0x300 drivers/net/tun.c:531
__tun_detach+0x3b9/0xa10 drivers/net/tun.c:571
tun_detach drivers/net/tun.c:594 [inline]
tun_chr_close+0x40/0x50 drivers/net/tun.c:2662
__fput+0x25e/0x6f0 fs/file_table.c:210
task_work_run+0x116/0x190 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x8f8/0x2800 kernel/exit.c:865
do_group_exit+0x100/0x2e0 kernel/exit.c:968
get_signal+0x4e5/0x1470 kernel/signal.c:2348
do_signal+0x8f/0x1660 arch/x86/kernel/signal.c:809
exit_to_usermode_loop+0x116/0x150 arch/x86/entry/common.c:159
prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
syscall_return_slowpath arch/x86/entry/common.c:267 [inline]
do_syscall_64+0x35d/0x4b0 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x447679
RSP: 002b:00007f2ef2c5ecf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00000000006ddc28 RCX: 0000000000447679
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00000000006ddc28
RBP: 00000000006ddc20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006ddc2c
R13: 00007ffc61b7646f R14: 00007f2ef2c5f9c0 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea00071a43c0 count:0 mapcount:0 mapping: (null) index:0x0
flags: 0x4000000000000000()
raw: 4000000000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 ffffea00071a43e0 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8801c690f580: 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 04 f2
ffff8801c690f600: f2 f2 f2 f2 f2 f2 00 f2 f2 f2 00 00 00 00 00 00
> ffff8801c690f680: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 04 f2 f2 f2
^
ffff8801c690f700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8801c690f780: 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 f2 f2
==================================================================


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches