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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 ffff88819a67f3c0 by task syz-executor.5/2477

CPU: 1 PID: 2477 Comm: syz-executor.5 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_backward+0xdc/0x220 kernel/events/core.c:6291
 __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_write_lock include/linux/rwlock_api_smp.h:210 [inline]
 _raw_write_lock+0x2a/0x40 kernel/locking/spinlock.c:296
 ext4_es_insert_extent+0x15b/0x570 fs/ext4/extents_status.c:722
 ext4_da_map_blocks fs/ext4/inode.c:1907 [inline]
 ext4_da_get_block_prep+0x758/0x1040 fs/ext4/inode.c:1972
 __block_write_begin_int+0x316/0x1070 fs/buffer.c:2027
 ext4_da_write_begin+0x49b/0x10c0 fs/ext4/inode.c:3121
 generic_perform_write+0x1d2/0x460 mm/filemap.c:3133
 __generic_file_write_iter+0x32e/0x550 mm/filemap.c:3258
 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:00007f92860eac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a679
RDX: 00000000175d900f RSI: 0000000020000200 RDI: 0000000000000004
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f92860eb6d4
R13: 00000000004cbb1d R14: 00000000004e5760 R15: 00000000ffffffff

The buggy address belongs to the page:
page:ffffea0006699fc0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x4000000000000000()
raw: 4000000000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 ffffea0006699fe0 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88819a67f280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88819a67f300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f1
>ffff88819a67f380: f1 f1 f1 f1 f1 04 f2 00 f3 f3 f3 00 00 00 00 00
                                           ^
 ffff88819a67f400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88819a67f480: 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 f1 f1 00
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