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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 ffff8881144c6c48 by task syz-executor.0/13352

CPU: 1 PID: 13352 Comm: syz-executor.0 Not tainted 4.14.156-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
 rq_lock kernel/sched/sched.h:1046 [inline]
 __schedule+0x1a8/0x1f80 kernel/sched/core.c:3385
 preempt_schedule_common+0x4f/0xd0 kernel/sched/core.c:3579
 ___preempt_schedule+0x16/0x18
 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock+0x3b/0x40 kernel/locking/spinlock.c:184
 spin_unlock include/linux/spinlock.h:357 [inline]
 ext4_unlock_group fs/ext4/ext4.h:3063 [inline]
 ext4_mb_regular_allocator+0x8ab/0xee0 fs/ext4/mballoc.c:2230
 ext4_mb_new_blocks+0x1575/0x39b0 fs/ext4/mballoc.c:4573
 ext4_ext_map_blocks+0x2307/0x4a40 fs/ext4/extents.c:4492
 ext4_map_blocks+0x7f4/0x1600 fs/ext4/inode.c:636
 _ext4_get_block+0x1ea/0x4c0 fs/ext4/inode.c:789
 ext4_get_block_trans+0x159/0x250 fs/ext4/inode.c:850
 ext4_dio_get_block+0x6a/0xb0 fs/ext4/inode.c:867
 get_more_blocks fs/direct-io.c:718 [inline]
 do_direct_IO fs/direct-io.c:1003 [inline]
 do_blockdev_direct_IO fs/direct-io.c:1336 [inline]
 __blockdev_direct_IO+0x30bd/0xe24e fs/direct-io.c:1422
 ext4_direct_IO_write fs/ext4/inode.c:3730 [inline]
 ext4_direct_IO+0xa4f/0x2820 fs/ext4/inode.c:3885
 generic_file_direct_write+0x1e4/0x430 mm/filemap.c:3036
 __generic_file_write_iter+0x209/0x550 mm/filemap.c:3215
 ext4_file_write_iter+0x58f/0xdb0 fs/ext4/file.c:268
 call_write_iter include/linux/fs.h:1798 [inline]
 new_sync_write fs/read_write.c:471 [inline]
 __vfs_write+0x401/0x5a0 fs/read_write.c:484
 vfs_write+0x17f/0x4d0 fs/read_write.c:546
 SYSC_write fs/read_write.c:594 [inline]
 SyS_write+0x102/0x250 fs/read_write.c:586
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a679
RSP: 002b:00007fda847b6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a679
RDX: 00000000175d900f RSI: 0000000020000200 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fda847b76d4
R13: 00000000004cb1ff R14: 00000000004e3fe8 R15: 00000000ffffffff

The buggy address belongs to the page:
page:ffffea0004513180 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:
 ffff8881144c6b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881144c6b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881144c6c00: f1 f1 f1 f1 f1 f1 04 f2 00 f3 f3 f3 00 00 00 00
                                              ^
 ffff8881144c6c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881144c6d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f1
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