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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 ffff8881a34776c0 by task syz-executor.2/22900

CPU: 1 PID: 22900 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_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:152
 alloc_object lib/debugobjects.c:150 [inline]
 __debug_object_init+0x1d2/0x7d0 lib/debugobjects.c:349
 __init_work+0x3f/0x50 kernel/workqueue.c:506
 alloc_tty_struct+0x3f5/0x7d0 drivers/tty/tty_io.c:2853
 pty_common_install drivers/tty/pty.c:399 [inline]
 pty_unix98_install+0x18d/0x730 drivers/tty/pty.c:740
 tty_driver_install_tty drivers/tty/tty_io.c:1225 [inline]
 tty_init_dev drivers/tty/tty_io.c:1338 [inline]
 tty_init_dev+0xe3/0x3a0 drivers/tty/tty_io.c:1315
 ptmx_open drivers/tty/pty.c:845 [inline]
 ptmx_open+0xe8/0x300 drivers/tty/pty.c:811
 chrdev_open+0x20e/0x560 fs/char_dev.c:423
 do_dentry_open+0x44e/0xe20 fs/open.c:789
 vfs_open+0x105/0x230 fs/open.c:903
 do_last fs/namei.c:3539 [inline]
 path_openat+0xb6c/0x2be0 fs/namei.c:3681
 do_filp_open+0x1a1/0x280 fs/namei.c:3715
 do_sys_open+0x2ca/0x590 fs/open.c:1096
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a679
RSP: 002b:00007f10fc46cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045a679
RDX: 0000000000000000 RSI: 0000000020000080 RDI: ffffffffffffff9c
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f10fc46d6d4
R13: 00000000004c7edc R14: 00000000004df0e0 R15: 00000000ffffffff

The buggy address belongs to the page:
page:ffffea00068d1dc0 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:
 ffff8881a3477580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881a3477600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f1
>ffff8881a3477680: f1 f1 f1 f1 f1 04 f2 00 f3 f3 f3 00 00 00 00 00
                                           ^
 ffff8881a3477700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881a3477780: 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00
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