WARNING: ODEBUG bug in exit_to_usermode_loop

Hello,

syzbot found the following issue on:

HEAD commit: d7e78d08 Linux 4.14.195
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=133466c1900000
kernel config: https://syzkaller.appspot.com/x/.config?x=6608b656f49b4e8c
dashboard link: https://syzkaller.appspot.com/bug?extid=de350037fbd1314911a8
compiler: gcc (GCC) 10.1.0-syz 20200507
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1152ca85900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

Bluetooth: hci2 command 0x0419 tx timeout
Bluetooth: hci1 command 0x0419 tx timeout
Bluetooth: hci3 command 0x0419 tx timeout
ODEBUG: free active (active state 1) object type: rcu_head hint: (null)
------------[ cut here ]------------
WARNING: CPU: 0 PID: 12040 at lib/debugobjects.c:287 debug_print_object.cold+0xa7/0xdb lib/debugobjects.c:287
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 12040 Comm: syz-executor.4 Not tainted 4.14.195-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x1b2/0x283 lib/dump_stack.c:58
panic+0x1f9/0x42d kernel/panic.c:183
__warn.cold+0x20/0x4b kernel/panic.c:547
report_bug+0x208/0x249 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:177 [inline]
fixup_bug arch/x86/kernel/traps.c:172 [inline]
do_error_trap+0x195/0x2d0 arch/x86/kernel/traps.c:295
invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:964
RIP: 0010:debug_print_object.cold+0xa7/0xdb lib/debugobjects.c:287
RSP: 0018:ffff88807d467d30 EFLAGS: 00010082
RAX: 0000000000000051 RBX: 0000000000000003 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff86ac12c0 RDI: ffffed100fa8cf9c
RBP: ffffffff86ab6440 R08: 0000000000000051 R09: 0000000000000000
R10: 0000000000000000 R11: ffff88808c22c040 R12: 0000000000000000
R13: 0000000000000001 R14: ffff88809eda9800 R15: ffff88808c4a57e0
__debug_check_no_obj_freed lib/debugobjects.c:747 [inline]
debug_check_no_obj_freed+0x3b7/0x674 lib/debugobjects.c:776
kmem_cache_free+0x156/0x2b0 mm/slab.c:3757
task_work_run+0x11f/0x190 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:191 [inline]
exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45d5b9
RSP: 002b:00007f0b5161ac78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e9
RAX: 0000000000000000 RBX: 0000000000002ac0 RCX: 000000000045d5b9
RDX: 0000000000000003 RSI: 0000000000000001 RDI: 0000000000000005
RBP: 000000000118cf88 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000000 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffee90cd3ef R14: 00007f0b5161b9c0 R15: 000000000118cf4c

======================================================


---
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HEAD commit: c37da90e Linux 4.19.143
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1682b7fe900000
kernel config: https://syzkaller.appspot.com/x/.config?x=d162ec57805c4e4d
dashboard link: https://syzkaller.appspot.com/bug?extid=55c67ce74d4586507d2f
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=116dc2f9900000
Reported-by: [email protected]

NOHZ: local_softirq_pending 08
Bluetooth: hci0: command 0x0406 tx timeout
------------[ cut here ]------------
WARNING: CPU: 0 PID: 16649 at lib/debugobjects.c:325 debug_print_object+0x160/0x250 lib/debugobjects.c:325
CPU: 0 PID: 16649 Comm: syz-executor.0 Not tainted 4.19.143-syzkaller #0
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2fe lib/dump_stack.c:118
panic+0x26a/0x50e kernel/panic.c:186
__warn.cold+0x20/0x61 kernel/panic.c:541
report_bug+0x262/0x2b0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:178 [inline]
fixup_bug arch/x86/kernel/traps.c:173 [inline]
do_error_trap+0x1d7/0x310 arch/x86/kernel/traps.c:296
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1038
RIP: 0010:debug_print_object+0x160/0x250 lib/debugobjects.c:325
Code: dd 40 1b cb 87 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 bf 00 00 00 48 8b 14 dd 40 1b cb 87 48 c7 c7 c0 10 cb 87 e8 bb f0 dc fd <0f> 0b 83 05 43 01 4e 06 01 48 83 c4 20 5b 5d 41 5c 41 5d c3 48 89
RSP: 0018:ffff88808f53fd98 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8154d001 RDI: ffffed1011ea7fa5
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000005 R11: ffffffff8ad3801b R12: ffffffff88d93700
R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000
__debug_check_no_obj_freed lib/debugobjects.c:785 [inline]
debug_check_no_obj_freed+0x271/0x482 lib/debugobjects.c:817
kmem_cache_free+0xff/0x260 mm/slab.c:3764
task_work_run+0x148/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:193 [inline]
exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167
prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
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:00007f3c511aec78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e9
R10: 0000000020000100 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007fff27b0030f R14: 00007f3c511af9c0 R15: 000000000118cf4c

syzbot suspects this issue was fixed by commit:

commit c5c6e00f6cc5d3ed0d6464b14e33f2f5c8505888
Author: Al Viro <[email protected]>
Date: Wed Sep 2 15:30:48 2020 +0000

fix regression in "epoll: Keep a reference on files added to the check list"

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=176d342b900000
start commit: 2f166cdc Linux 4.14.196
git tree: linux-4.14.y
kernel config: https://syzkaller.appspot.com/x/.config?x=e2677667b00dfecb
dashboard link: https://syzkaller.appspot.com/bug?extid=de350037fbd1314911a8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10e30001900000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: fix regression in "epoll: Keep a reference on files added to the check list"

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

commit dff6a2c2828bce13f32c62029def97195f8830f6
Author: Christophe JAILLET <[email protected]>
Date: Fri Aug 21 07:58:19 2020 +0000

nvmet-fc: Fix a missed _irqsave version of spin_lock in 'nvmet_fc_fod_op_done()'

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13f5a2e0500000
start commit: c37da90e Linux 4.19.143
git tree: linux-4.19.y
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1683c219900000
#syz fix: nvmet-fc: Fix a missed _irqsave version of spin_lock in 'nvmet_fc_fod_op_done()'