Subject: Re: WARNING: ODEBUG bug in __do_softirq

From: syzbot <[email-masked]>
Date: Wed, 26 Aug 2020 01:54:16 -0700

syzbot has found a reproducer for the following issue on:

HEAD commit:    3a00d3df Add linux-next specific files for 20200825
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=15080fa9900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9ef0a5f95935d447
dashboard link: https://syzkaller.appspot.com/bug?extid=51c9bdfa559769d2f897
compiler:       gcc (GCC) 10.1.0-syz 20200507
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17927a2e900000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=132b8ede900000

The issue was bisected to:

commit 5b317cbf2bcb85a1e96ce87717cb991ecab1dd4d
Author: Rafael J. Wysocki <[email-masked]>
Date:   Fri Feb 22 09:17:11 2019 +0000

    Merge branch 'pm-cpufreq-fixes'

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=171ead5d200000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=149ead5d200000
console output: https://syzkaller.appspot.com/x/log.txt?x=109ead5d200000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]
Fixes: 5b317cbf2bcb ("Merge branch 'pm-cpufreq-fixes'")

------------[ cut here ]------------
ODEBUG: free active (active state 0) object type: work_struct hint: afs_manage_cell+0x0/0x11c0 fs/afs/cell.c:498
WARNING: CPU: 1 PID: 16 at lib/debugobjects.c:485 debug_print_object+0x160/0x250 lib/debugobjects.c:485
Modules linked in:
CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.9.0-rc2-next-20200825-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:debug_print_object+0x160/0x250 lib/debugobjects.c:485
Code: dd 60 56 94 88 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 bf 00 00 00 48 8b 14 dd 60 56 94 88 48 c7 c7 c0 4b 94 88 e8 eb bd a4 fd <0f> 0b 83 05 13 50 1b 07 01 48 83 c4 20 5b 5d 41 5c 41 5d c3 48 89
RSP: 0018:ffffc90000d7fbf8 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: ffff8880a9686440 RSI: ffffffff815da937 RDI: fffff520001aff71
RBP: 0000000000000001 R08: 0000000000000001 R09: ffff8880ae720f8b
R10: 0000000000000000 R11: 203a47554245444f R12: ffffffff89ba35e0
R13: ffffffff814b6290 R14: dead000000000100 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9120aabe78 CR3: 0000000088b2e000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __debug_check_no_obj_freed lib/debugobjects.c:967 [inline]
 debug_check_no_obj_freed+0x301/0x41c lib/debugobjects.c:998
 kfree+0xf0/0x2c0 mm/slab.c:3755
 rcu_do_batch kernel/rcu/tree.c:2474 [inline]
 rcu_core+0x61e/0x1220 kernel/rcu/tree.c:2709
 __do_softirq+0x2de/0xa24 kernel/softirq.c:298
 run_ksoftirqd kernel/softirq.c:652 [inline]
 run_ksoftirqd+0x89/0x100 kernel/softirq.c:644
 smpboot_thread_fn+0x655/0x9e0 kernel/smpboot.c:165
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294