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BUG: KASAN: stack-out-of-bounds in unwind_next_frame.part.0+0x872/0xa20 arch/x86/kernel/unwind_frame.c:327
Read of size 8 at addr ffff88805bce7a88 by task syz-executor.5/4708

CPU: 0 PID: 4708 Comm: syz-executor.5 Not tainted 5.1.0-rc6 #79
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+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
 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+0x46/0x60 arch/x86/kernel/stacktrace.c:69
 proc_pid_stack+0x1c4/0x2c0 fs/proc/base.c:442
 proc_single_show+0xf6/0x170 fs/proc/base.c:744
 seq_read+0x4db/0x1130 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+0x4a9/0x660 fs/read_write.c:922
 vfs_readv+0xf0/0x160 fs/read_write.c:984
 do_preadv+0x1c4/0x280 fs/read_write.c:1068
 __do_sys_preadv fs/read_write.c:1118 [inline]
 __se_sys_preadv fs/read_write.c:1113 [inline]
 __x64_sys_preadv+0x9a/0xf0 fs/read_write.c:1113
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x458c29
Code: ad b8 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 b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fd38676ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000458c29
RDX: 10000000000001b6 RSI: 0000000020000480 RDI: 0000000000000003
RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd38676b6d4
R13: 00000000004c5969 R14: 00000000004d9cc8 R15: 00000000ffffffff

The buggy address belongs to the page:
page:ffffea00016f39c0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x1fffc0000000000()
raw: 01fffc0000000000 0000000000000000 ffffffff016f0101 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88805bce7980: 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 f3 f3
 ffff88805bce7a00: f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88805bce7a80: f1 f1 f1 f1 00 f2 f2 f2 00 00 00 00 00 00 00 00
                      ^
 ffff88805bce7b00: 00 f2 f2 f2 f2 f2 00 00 00 00 00 00 00 00 00 00
 ffff88805bce7b80: 00 00 00 00 f3 f3 f3 f3 00 00 00 00 00 00 00 00
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