Re: [syzbot] WARNING: ODEBUG bug in batadv_nc_mesh_free

From: Pavel Skripkin
Date: Fri Oct 22 2021 - 15:36:13 EST


On 10/22/21 21:41, syzbot wrote:
Hello,

syzbot found the following issue on:

HEAD commit: e0bfcf9c77d9 Merge tag 'mlx5-fixes-2021-10-20' of git://gi..
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=17900a0cb00000
kernel config: https://syzkaller.appspot.com/x/.config?x=bab9d35f204746a7
dashboard link: https://syzkaller.appspot.com/bug?extid=1dca817d274a3fb19f2b
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=144d76b4b00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14732b80b00000

Bisection is inconclusive: the issue happens on the oldest tested release.

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=14093652b00000
final oops: https://syzkaller.appspot.com/x/report.txt?x=16093652b00000
console output: https://syzkaller.appspot.com/x/log.txt?x=12093652b00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1dca817d274a3fb19f2b@xxxxxxxxxxxxxxxxxxxxxxxxx

R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
------------[ cut here ]------------
ODEBUG: assert_init not available (active state 0) object type: timer_list hint: 0x0
WARNING: CPU: 0 PID: 6548 at lib/debugobjects.c:505 debug_print_object+0x16e/0x250 lib/debugobjects.c:505
Modules linked in:
CPU: 0 PID: 6548 Comm: syz-executor286 Not tainted 5.15.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:debug_print_object+0x16e/0x250 lib/debugobjects.c:505
Code: ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 af 00 00 00 48 8b 14 dd 80 3e e4 89 4c 89 ee 48 c7 c7 80 32 e4 89 e8 5e 1d 15 05 <0f> 0b 83 05 d5 39 90 09 01 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e c3
RSP: 0018:ffffc90002d7ecc0 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000000000
RDX: ffff8880163c8000 RSI: ffffffff815e88a8 RDI: fffff520005afd8a
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815e264e R11: 0000000000000000 R12: ffffffff898de560
R13: ffffffff89e43900 R14: ffffffff81658550 R15: 1ffff920005afda3
FS: 0000555555c03300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fef3003e098 CR3: 0000000073ad0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
debug_object_assert_init lib/debugobjects.c:895 [inline]
debug_object_assert_init+0x1f4/0x2e0 lib/debugobjects.c:866
debug_timer_assert_init kernel/time/timer.c:739 [inline]
debug_assert_init kernel/time/timer.c:784 [inline]
del_timer+0x6d/0x110 kernel/time/timer.c:1204
try_to_grab_pending+0x6d/0xd0 kernel/workqueue.c:1270
__cancel_work_timer+0xa6/0x570 kernel/workqueue.c:3129
batadv_nc_mesh_free+0x41/0x120 net/batman-adv/network-coding.c:1869
batadv_mesh_free+0x7d/0x170 net/batman-adv/main.c:245
batadv_mesh_init+0x62f/0x710 net/batman-adv/main.c:226

Same fault injection, same backtrace, same warning... Looks like duplicate.

#syz dup: WARNING in batadv_nc_mesh_free


With regards,
Pavel Skripkin