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BUG: KASAN: stack-out-of-bounds in unwind_next_frame+0x169f/0x1810 arch/x86/kernel/unwind_orc.c:470
Read of size 8 at addr ffff88819b7afcd8 by task syz-executor.2/3898

CPU: 0 PID: 3898 Comm: syz-executor.2 Not tainted 4.14.157-syzkaller #0
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xe5/0x154 lib/dump_stack.c:58
 print_address_description+0x60/0x226 mm/kasan/report.c:187
 __kasan_report.cold+0x1a/0x41 mm/kasan/report.c:316
 unwind_next_frame+0x169f/0x1810 arch/x86/kernel/unwind_orc.c:470
 perf_callchain_kernel+0x3a0/0x540 arch/x86/events/core.c:2338
 get_perf_callchain+0x2f5/0x770 kernel/events/callchain.c:217
 perf_callchain+0x147/0x190 kernel/events/callchain.c:190
 perf_prepare_sample+0x6a8/0x1360 kernel/events/core.c:6149
 __perf_event_output kernel/events/core.c:6265 [inline]
 perf_event_output_forward+0xdc/0x220 kernel/events/core.c:6283
 __perf_event_overflow+0x12d/0x340 kernel/events/core.c:7541
 perf_swevent_overflow+0x7a/0xf0 kernel/events/core.c:7617
 perf_swevent_event+0x112/0x270 kernel/events/core.c:7655
 perf_tp_event+0x633/0x7f0 kernel/events/core.c:8079
 perf_trace_run_bpf_submit kernel/events/core.c:8049 [inline]
 perf_trace_run_bpf_submit+0x113/0x170 kernel/events/core.c:8035
 perf_trace_lock_acquire+0x341/0x4e0 include/trace/events/lock.h:13
 trace_lock_acquire include/trace/events/lock.h:13 [inline]
 lock_acquire+0x279/0x360 kernel/locking/lockdep.c:3993
 __raw_spin_trylock include/linux/spinlock_api_smp.h:90 [inline]
 _raw_spin_trylock kernel/locking/spinlock.c:136 [inline]
 _raw_spin_trylock+0x60/0x70 kernel/locking/spinlock.c:134
 spin_trylock include/linux/spinlock.h:327 [inline]
 dentry_kill fs/dcache.c:620 [inline]
 dput.part.0+0x45c/0x710 fs/dcache.c:847
 dput+0x1b/0x30 fs/dcache.c:811
 __fput+0x429/0x710 fs/file_table.c:228
 task_work_run+0x125/0x1a0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x13b/0x160 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x3a3/0x520 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a679
RSP: 002b:00007fc7f28edc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 000000000045a679
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000000b
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc7f28ee6d4
R13: 00000000004fd772 R14: 00000000004d4958 R15: 00000000ffffffff

The buggy address belongs to the page:
page:ffffea00066debc0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x4000000000000000()
raw: 4000000000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 dead000000000200 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88819b7afb80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88819b7afc00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88819b7afc80: 00 00 f1 f1 f1 f1 f1 f1 04 f2 00 f3 f3 f3 00 00
                                                    ^
 ffff88819b7afd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88819b7afd80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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