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BUG: KASAN: stack-out-of-bounds in ptrace_reparented include/linux/ptrace.h:92 [inline]
BUG: KASAN: stack-out-of-bounds in wait_consider_task+0x3792/0x39b0 kernel/exit.c:1374
Read of size 8 at addr ffff88019dc068e8 by task syz-executor7/4494

CPU: 1 PID: 4494 Comm: syz-executor7 Not tainted 4.18.0-rc3+ #46
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+0x1c9/0x2b4 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 ptrace_reparented include/linux/ptrace.h:92 [inline]
 wait_consider_task+0x3792/0x39b0 kernel/exit.c:1374
 do_wait_thread kernel/exit.c:1451 [inline]
 do_wait+0x477/0xb80 kernel/exit.c:1522
 kernel_wait4+0x247/0x3f0 kernel/exit.c:1665
 __do_sys_wait4+0x137/0x150 kernel/exit.c:1677
 __se_sys_wait4 kernel/exit.c:1673 [inline]
 __x64_sys_wait4+0x97/0xf0 kernel/exit.c:1673
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x40fdba
Code: 0f 83 1a 17 00 00 c3 66 0f 1f 84 00 00 00 00 00 8b 05 de 61 63 00 85 c0 75 36 45 31 d2 48 63 d2 48 63 ff b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 06 c3 0f 1f 44 00 00 48 c7 c2 d4 ff ff ff f7 
RSP: 002b:00007ffc015eb998 EFLAGS: 00000246 ORIG_RAX: 000000000000003d
RAX: ffffffffffffffda RBX: 000000000000e552 RCX: 000000000040fdba
RDX: 0000000040000001 RSI: 00007ffc015eb9b4 RDI: ffffffffffffffff
RBP: 0000000000000000 R08: 0000000000000001 R09: 000000000141a940
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000b
R13: 000000000000012e R14: 00007ffc015ec040 R15: 000000000000e531

Allocated by task 4494:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
 kmem_cache_alloc_node+0x144/0x780 mm/slab.c:3644
 alloc_task_struct_node kernel/fork.c:157 [inline]
 dup_task_struct kernel/fork.c:779 [inline]
 copy_process.part.40+0x16b5/0x7220 kernel/fork.c:1641
 copy_process kernel/fork.c:1616 [inline]
 _do_fork+0x291/0x12a0 kernel/fork.c:2099
 __do_sys_clone kernel/fork.c:2206 [inline]
 __se_sys_clone kernel/fork.c:2200 [inline]
 __x64_sys_clone+0xbf/0x150 kernel/fork.c:2200
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff88019dc06440
 which belongs to the cache task_struct(49:syz7) of size 5952
The buggy address is located 1192 bytes inside of
 5952-byte region [ffff88019dc06440, ffff88019dc07b80)
The buggy address belongs to the page:
page:ffffea0006770180 count:1 mapcount:0 mapping:ffff88019e8627c0 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffffea0007214388 ffffea0007221108 ffff88019e8627c0
raw: 0000000000000000 ffff88019dc06440 0000000100000001 ffff8801d889c180
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff8801d889c180

Memory state around the buggy address:
 ffff88019dc06780: f2 f2 f2 f2 f2 f8 f2 f2 f2 f2 f2 f2 f2 00 f2 f2
 ffff88019dc06800: f2 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88019dc06880: 00 00 00 00 00 00 f1 f1 f1 f1 00 f2 f2 f2 f2 f2
                                                          ^
 ffff88019dc06900: f2 f2 00 f2 f2 f2 f2 f2 f2 f2 00 f2 f2 f2 f2 f2
 ffff88019dc06980: f2 f2 f8 f2 f2 f2 f2 f2 f2 f2 00 f2 f2 f2 00 00
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