WARNING: ODEBUG bug in get

WARNING: ODEBUG bug in get_signal
Status: upstream: reported syz repro on 2020/08/27 07:58
Reported-by: syzbot+e3cf8f93cf86936710db@syzkaller.appspotmail.com
First crash: 26d, last: 18d

Cause bisection: introduced by (bisect log):

commit a9ed4a6560b8562b7e2e2bed9527e88001f7b682
Author: Marc Zyngier <maz@kernel.org>
Date: Wed Aug 19 16:12:17 2020 +0000

epoll: Keep a reference on files added to the check list

Crash: WARNING in corrupted (log)
Repro: syz .config

similar bugs (2):
Kernel	Title	Repro	Bisected	Count	Last	Reported	Patched	Status
linux-4.14	WARNING: ODEBUG bug in get_signal			1	16d	16d	0/1	upstream: reported on 2020/09/05 14:38
linux-4.19	WARNING: ODEBUG bug in get_signal	syz		3	16d	25d	0/1	upstream: reported syz repro on 2020/08/27 09:14

Sample crash report:

------------[ cut here ]------------
ODEBUG: free active (active state 1) object type: rcu_head hint: 0x0
WARNING: CPU: 1 PID: 7102 at lib/debugobjects.c:485 debug_print_object+0x160/0x250 lib/debugobjects.c:485
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 7102 Comm: syz-executor.0 Not tainted 5.9.0-rc2-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+0x18f/0x20d lib/dump_stack.c:118
 panic+0x2e3/0x75c kernel/panic.c:231
 __warn.cold+0x20/0x4a kernel/panic.c:600
 report_bug+0x1bd/0x210 lib/bug.c:198
 handle_bug+0x38/0x90 arch/x86/kernel/traps.c:234
 exc_invalid_op+0x14/0x40 arch/x86/kernel/traps.c:254
 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536
RIP: 0010:debug_print_object+0x160/0x250 lib/debugobjects.c:485
Code: dd e0 26 94 88 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 bf 00 00 00 48 8b 14 dd e0 26 94 88 48 c7 c7 40 1c 94 88 e8 d2 36 a6 fd <0f> 0b 83 05 93 4f 13 07 01 48 83 c4 20 5b 5d 41 5c 41 5d c3 48 89
RSP: 0018:ffffc90001c37ba8 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: ffff888099c76180 RSI: ffffffff815dafc7 RDI: fffff52000386f67
RBP: 0000000000000001 R08: 0000000000000001 R09: ffff8880ae720f8b
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff89bd6780
R13: 0000000000000000 R14: dead000000000100 R15: dffffc0000000000
 __debug_check_no_obj_freed lib/debugobjects.c:967 [inline]
 debug_check_no_obj_freed+0x301/0x41c lib/debugobjects.c:998
 kmem_cache_free.part.0+0x16d/0x1f0 mm/slab.c:3692
 task_work_run+0xdd/0x190 kernel/task_work.c:141
 get_signal+0xd89/0x1f00 kernel/signal.c:2561
 arch_do_signal+0x82/0x2520 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:136 [inline]
 exit_to_user_mode_prepare+0x15d/0x1c0 kernel/entry/common.c:167
 syscall_exit_to_user_mode+0x59/0x2b0 kernel/entry/common.c:242
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45d5b9
Code: 5d b4 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 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f0391acbc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e9
RAX: 0000000000000000 RBX: 0000000000002ac0 RCX: 000000000045d5b9
RDX: 0000000000000005 RSI: 0000000000000001 RDI: 0000000000000006
RBP: 000000000118cf88 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000000 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffffcf2e40f R14: 00007f0391acc9c0 R15: 000000000118cf4c
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (9):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	Maintainers
ci-upstream-kasan-gce-selinux-root	2020/08/27 10:56	upstream	15bc20c6	816e0689	.config	log	report	syz	axboe@kernel.dk, linux-kernel@vger.kernel.org, oleg@redhat.com, peterz@infradead.org
ci-upstream-kasan-gce-root	2020/08/27 09:16	upstream	15bc20c6	816e0689	.config	log	report	syz	axboe@kernel.dk, linux-kernel@vger.kernel.org, oleg@redhat.com, peterz@infradead.org
ci-upstream-kasan-gce-smack-root	2020/08/27 08:10	upstream	15bc20c6	816e0689	.config	log	report	syz	axboe@kernel.dk, linux-kernel@vger.kernel.org, oleg@redhat.com, peterz@infradead.org
ci-upstream-kasan-gce-386	2020/08/27 05:40	upstream	15bc20c6	318430cb	.config	log	report	syz	axboe@kernel.dk, linux-kernel@vger.kernel.org, oleg@redhat.com, peterz@infradead.org
ci-upstream-net-kasan-gce	2020/09/03 18:49	net-next	22b330b6	abf9ba4f	.config	log	report	syz	axboe@kernel.dk, linux-kernel@vger.kernel.org, oleg@redhat.com, peterz@infradead.org
ci-upstream-linux-next-kasan-gce-root	2020/09/01 08:19	linux-next	b36c9697	d5a3ae1f	.config	log	report	syz	axboe@kernel.dk, linux-kernel@vger.kernel.org, oleg@redhat.com, peterz@infradead.org
ci-upstream-linux-next-kasan-gce-root	2020/08/27 04:51	linux-next	f37be724	318430cb	.config	log	report	syz	axboe@kernel.dk, linux-kernel@vger.kernel.org, oleg@redhat.com, peterz@infradead.org
ci-upstream-net-this-kasan-gce	2020/09/03 21:25	net	8b4a11c6	abf9ba4f	.config	log	report		axboe@kernel.dk, linux-kernel@vger.kernel.org, oleg@redhat.com, peterz@infradead.org
ci-upstream-net-kasan-gce	2020/08/26 21:41	net-next	ea416e27	318430cb	.config	log	report		axboe@kernel.dk, linux-kernel@vger.kernel.org, oleg@redhat.com, peterz@infradead.org