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BUG: KASAN: out-of-bounds in unwind_next_frame.part.0+0x872/0xa20 arch/x86/kernel/unwind_frame.c:327
Read of size 8 at addr ffff88808a64faa8 by task syz-executor.0/18514

CPU: 1 PID: 18514 Comm: syz-executor.0 Not tainted 4.19.85-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report mm/kasan/report.c:412 [inline]
 kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:396
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 unwind_next_frame.part.0+0x872/0xa20 arch/x86/kernel/unwind_frame.c:327
 unwind_next_frame+0x3b/0x50 arch/x86/kernel/unwind_frame.c:287
 __save_stack_trace+0x83/0x100 arch/x86/kernel/stacktrace.c:44
 save_stack_trace_tsk arch/x86/kernel/stacktrace.c:76 [inline]
 save_stack_trace_tsk+0x9e/0xd0 arch/x86/kernel/stacktrace.c:69
 proc_pid_stack+0x1c4/0x2c0 fs/proc/base.c:456
 proc_single_show+0xf0/0x180 fs/proc/base.c:755
 seq_read+0x4ca/0x1110 fs/seq_file.c:229
 do_loop_readv_writev fs/read_write.c:701 [inline]
 do_loop_readv_writev fs/read_write.c:688 [inline]
 do_iter_read+0x490/0x640 fs/read_write.c:925
 vfs_readv+0xf0/0x160 fs/read_write.c:987
 do_preadv+0x1c4/0x280 fs/read_write.c:1071
 __do_sys_preadv fs/read_write.c:1121 [inline]
 __se_sys_preadv fs/read_write.c:1116 [inline]
 __x64_sys_preadv+0x9a/0xf0 fs/read_write.c:1116
 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45a639
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f797b9d1c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045a639
RDX: 10000000000002a1 RSI: 0000000020000480 RDI: 0000000000000004
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f797b9d26d4
R13: 00000000004c7eb1 R14: 00000000004dddd0 R15: 00000000ffffffff

The buggy address belongs to the page:
page:ffffea00022993c0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x1fffc0000000000()
raw: 01fffc0000000000 0000000000000000 ffffffff02290101 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808a64f980: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00
 ffff88808a64fa00: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88808a64fa80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                     ^
 ffff88808a64fb00: 00 00 00 00 f1 f1 f1 f1 00 f3 f3 f3 00 00 00 00
 ffff88808a64fb80: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
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