WARNING: ODEBUG bug in free_task

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: d573e8a7 Linux 4.19.75
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=119f2b09600000
kernel config: https://syzkaller.appspot.com/x/.config?x=50b385e67c7b7cdf
dashboard link: https://syzkaller.appspot.com/bug?extid=af33a6610afb8054cf3f
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+af33a6...@syzkaller.appspotmail.com

------------[ cut here ]------------
ODEBUG: free active (active state 1) object type: rcu_head hint:
(null)
WARNING: CPU: 1 PID: 20260 at lib/debugobjects.c:325
debug_print_object+0x168/0x250 lib/debugobjects.c:325
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 20260 Comm: syz-executor.2 Not tainted 4.19.75 #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+0x172/0x1f0 lib/dump_stack.c:113
panic+0x263/0x507 kernel/panic.c:185
kobject: 'lo' (00000000541c3176): kobject_uevent_env
__warn.cold+0x20/0x4a kernel/panic.c:540
report_bug+0x263/0x2b0 lib/bug.c:186
sctp: [Deprecated]: syz-executor.0 (pid 20280) Use of struct
sctp_assoc_value in delayed_ack socket option.
Use struct sctp_sack_info instead
fixup_bug arch/x86/kernel/traps.c:178 [inline]
fixup_bug arch/x86/kernel/traps.c:173 [inline]
do_error_trap+0x204/0x360 arch/x86/kernel/traps.c:296
kobject: 'lo' (00000000541c3176): fill_kobj_path: path
= '/devices/virtual/net/lo'
kobject: 'queues' (0000000087a0a117): kobject_add_internal: parent: 'lo',
set: '<NULL>'
do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1037
RIP: 0010:debug_print_object+0x168/0x250 lib/debugobjects.c:325
kobject: '9p-21' (000000007c3620e2): kobject_add_internal: parent: 'bdi',
set: 'devices'
Code: dd 20 56 82 87 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 b5 00 00 00 48
8b 14 dd 20 56 82 87 48 c7 c7 60 4b 82 87 e8 d6 04 19 fe <0f> 0b 83 05 cb
83 17 06 01 48 83 c4 20 5b 41 5c 41 5d 41 5e 5d c3
RSP: 0018:ffff88809f44f9d0 EFLAGS: 00010082
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8155dbd6 RDI: ffffed1013e89f2c
RBP: ffff88809f44fa10 R08: ffff88809f9ca040 R09: ffffed1015d23ee3
kobject: '9p-21' (000000007c3620e2): kobject_uevent_env
R10: ffffed1015d23ee2 R11: ffff8880ae91f717 R12: 0000000000000001
R13: ffffffff8879f200 R14: 0000000000000000 R15: ffff88808ecf56a0
__debug_check_no_obj_freed lib/debugobjects.c:785 [inline]
debug_check_no_obj_freed+0x29f/0x464 lib/debugobjects.c:817
kobject: '9p-21' (000000007c3620e2): fill_kobj_path: path
= '/devices/virtual/bdi/9p-21'
kmem_cache_free+0x18f/0x260 mm/slab.c:3764
free_task_struct kernel/fork.c:162 [inline]
free_task+0xdd/0x120 kernel/fork.c:416
kobject: 'queues' (0000000087a0a117): kobject_uevent_env
__put_task_struct+0x20f/0x4c0 kernel/fork.c:689
put_task_struct include/linux/sched/task.h:96 [inline]
finish_task_switch+0x52b/0x780 kernel/sched/core.c:2710
context_switch kernel/sched/core.c:2829 [inline]
__schedule+0x86e/0x1dc0 kernel/sched/core.c:3474
kobject: 'queues' (0000000087a0a117): kobject_uevent_env: filter function
caused the event to drop!
schedule+0x92/0x1c0 kernel/sched/core.c:3518
freezable_schedule include/linux/freezer.h:172 [inline]
do_nanosleep+0x201/0x690 kernel/time/hrtimer.c:1688
kobject: 'rx-0' (00000000064c3552): kobject_add_internal: parent: 'queues',
set: 'queues'
kobject: 'rx-0' (00000000064c3552): kobject_uevent_env
hrtimer_nanosleep+0x2a6/0x570 kernel/time/hrtimer.c:1742
kobject: 'rx-0' (00000000064c3552): fill_kobj_path: path
= '/devices/virtual/net/lo/queues/rx-0'
__do_sys_nanosleep kernel/time/hrtimer.c:1776 [inline]
__se_sys_nanosleep kernel/time/hrtimer.c:1763 [inline]
__x64_sys_nanosleep+0x1a6/0x220 kernel/time/hrtimer.c:1763
kobject: 'tx-0' (00000000f9c6c5a5): kobject_add_internal: parent: 'queues',
set: 'queues'
kobject: 'tx-0' (00000000f9c6c5a5): kobject_uevent_env
do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457ed1
kobject: 'tx-0' (00000000f9c6c5a5): fill_kobj_path: path
= '/devices/virtual/net/lo/queues/tx-0'
Code: 75 14 b8 23 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 24 d3 fb ff c3 48
83 ec 08 e8 ea 46 00 00 48 89 04 24 b8 23 00 00 00 0f 05 <48> 8b 3c 24 48
89 c2 e8 33 47 00 00 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ffcc89c5060 EFLAGS: 00000293 ORIG_RAX: 0000000000000023
RAX: ffffffffffffffda RBX: 0000000000081c32 RCX: 0000000000457ed1
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffcc89c5070
RBP: 0000000000000001 R08: ffffffffffffffff R09: ffffffffffffffff
kobject: 'ip_vti0' (000000006fdcb711): kobject_cleanup, parent
(null)
R10: 00007ffcc89c5160 R11: 0000000000000293 R12: 000000000075bf20
R13: 000000000075c9a0 R14: 0000000000760f60 R15: 000000000075bf2c
Kernel Offset: disabled

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


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit: d573e8a7 Linux 4.19.75
git tree: linux-4.19.y

console output: https://syzkaller.appspot.com/x/log.txt?x=17e2bdad600000

kernel config: https://syzkaller.appspot.com/x/.config?x=50b385e67c7b7cdf
dashboard link: https://syzkaller.appspot.com/bug?extid=af33a6610afb8054cf3f
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13b443ad600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+af33a6...@syzkaller.appspotmail.com

8021q: adding VLAN 0 to HW filter on device batadv0
audit: type=1400 audit(1569208280.896:38): avc: denied { associate } for
pid=7553 comm="syz-executor.0" name="syz0"
scontext=unconfined_u:object_r:unlabeled_t:s0
tcontext=system_u:object_r:unlabeled_t:s0 tclass=filesystem permissive=1

------------[ cut here ]------------
ODEBUG: free active (active state 1) object type: rcu_head hint:
(null)

WARNING: CPU: 0 PID: 8157 at lib/debugobjects.c:325

debug_print_object+0x168/0x250 lib/debugobjects.c:325
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 8157 Comm: syz-executor.0 Not tainted 4.19.75 #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+0x172/0x1f0 lib/dump_stack.c:113
panic+0x263/0x507 kernel/panic.c:185

__warn.cold+0x20/0x4a kernel/panic.c:540
report_bug+0x263/0x2b0 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+0x204/0x360 arch/x86/kernel/traps.c:296

do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1037
RIP: 0010:debug_print_object+0x168/0x250 lib/debugobjects.c:325

Code: dd 20 56 82 87 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 b5 00 00 00 48
8b 14 dd 20 56 82 87 48 c7 c7 60 4b 82 87 e8 d6 04 19 fe <0f> 0b 83 05 cb
83 17 06 01 48 83 c4 20 5b 41 5c 41 5d 41 5e 5d c3

RSP: 0018:ffff8880a38f76f8 EFLAGS: 00010086

RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000

RDX: 0000000000000000 RSI: ffffffff8155dbd6 RDI: ffffed101471eed1
RBP: ffff8880a38f7738 R08: ffff888092f203c0 R09: ffffed1015d03ee3
R10: ffffed1015d03ee2 R11: ffff8880ae81f717 R12: 0000000000000001
R13: ffffffff8879f200 R14: 0000000000000000 R15: ffff88808eb235a0

__debug_check_no_obj_freed lib/debugobjects.c:785 [inline]
debug_check_no_obj_freed+0x29f/0x464 lib/debugobjects.c:817

kmem_cache_free+0x18f/0x260 mm/slab.c:3764
free_task_struct kernel/fork.c:162 [inline]
free_task+0xdd/0x120 kernel/fork.c:416

__put_task_struct+0x20f/0x4c0 kernel/fork.c:689
put_task_struct include/linux/sched/task.h:96 [inline]
finish_task_switch+0x52b/0x780 kernel/sched/core.c:2710
context_switch kernel/sched/core.c:2829 [inline]
__schedule+0x86e/0x1dc0 kernel/sched/core.c:3474

schedule+0x92/0x1c0 kernel/sched/core.c:3518
freezable_schedule include/linux/freezer.h:172 [inline]

futex_wait_queue_me+0x30c/0x600 kernel/futex.c:2607
futex_wait+0x228/0x5e0 kernel/futex.c:2722
do_futex+0x175/0x1d70 kernel/futex.c:3646
__do_sys_futex kernel/futex.c:3707 [inline]
__se_sys_futex kernel/futex.c:3675 [inline]
__x64_sys_futex+0x400/0x590 kernel/futex.c:3675
do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459a09
Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f59f398ccf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 000000000075c078 RCX: 0000000000459a09
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000075c078
RBP: 000000000075c070 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000075c07c
R13: 00007fff88cee39f R14: 00007f59f398d9c0 R15: 000000000075c07c

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

[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit: d573e8a7 Linux 4.19.75
git tree: linux-4.19.y

console output: https://syzkaller.appspot.com/x/log.txt?x=13ac9f03600000

kernel config: https://syzkaller.appspot.com/x/.config?x=50b385e67c7b7cdf
dashboard link: https://syzkaller.appspot.com/bug?extid=af33a6610afb8054cf3f
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11a4344d600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17c93de9600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+af33a6...@syzkaller.appspotmail.com

------------[ cut here ]------------
ODEBUG: free active (active state 1) object type: rcu_head hint:
(null)

WARNING: CPU: 0 PID: 0 at lib/debugobjects.c:325

debug_print_object+0x168/0x250 lib/debugobjects.c:325
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.19.75 #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+0x172/0x1f0 lib/dump_stack.c:113
panic+0x263/0x507 kernel/panic.c:185

__warn.cold+0x20/0x4a kernel/panic.c:540
report_bug+0x263/0x2b0 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+0x204/0x360 arch/x86/kernel/traps.c:296

do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1037
RIP: 0010:debug_print_object+0x168/0x250 lib/debugobjects.c:325

Code: dd 20 56 82 87 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 b5 00 00 00 48
8b 14 dd 20 56 82 87 48 c7 c7 60 4b 82 87 e8 d6 04 19 fe <0f> 0b 83 05 cb
83 17 06 01 48 83 c4 20 5b 41 5c 41 5d 41 5e 5d c3

RSP: 0018:ffffffff88607a58 EFLAGS: 00010082

RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000

RDX: 0000000000000000 RSI: ffffffff8155dbd6 RDI: fffffbfff10c0f3d
RBP: ffffffff88607a98 R08: ffffffff88679ec0 R09: ffffed1015d03ee3
R10: ffffed1015d03ee2 R11: ffff8880ae81f717 R12: 0000000000000001
R13: ffffffff8879f200 R14: 0000000000000000 R15: ffff88807a9078a0

__debug_check_no_obj_freed lib/debugobjects.c:785 [inline]
debug_check_no_obj_freed+0x29f/0x464 lib/debugobjects.c:817

kmem_cache_free+0x18f/0x260 mm/slab.c:3764
free_task_struct kernel/fork.c:162 [inline]
free_task+0xdd/0x120 kernel/fork.c:416

__put_task_struct+0x20f/0x4c0 kernel/fork.c:689
put_task_struct include/linux/sched/task.h:96 [inline]
finish_task_switch+0x52b/0x780 kernel/sched/core.c:2710
context_switch kernel/sched/core.c:2829 [inline]
__schedule+0x86e/0x1dc0 kernel/sched/core.c:3474

schedule_idle+0x58/0x80 kernel/sched/core.c:3545
do_idle+0x192/0x560 kernel/sched/idle.c:286
cpu_startup_entry+0xc8/0xe0 kernel/sched/idle.c:368
rest_init+0x219/0x222 init/main.c:442
start_kernel+0x88c/0x8c5 init/main.c:738
x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:472
x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:453
secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243

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

[syzbot]

syzbot suspects this bug was fixed by commit:

commit 4eb92a1148342af1d6f82018d20cd862e1d3ab7e
Author: Leon Romanovsky <leo...@mellanox.com>
Date: Thu Oct 11 19:10:10 2018 +0000

RDMA/restrack: Protect from reentry to resource return path

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1290842ae00000
start commit: d573e8a7 Linux 4.19.75
git tree: linux-4.19.y

kernel config: https://syzkaller.appspot.com/x/.config?x=50b385e67c7b7cdf
dashboard link: https://syzkaller.appspot.com/bug?extid=af33a6610afb8054cf3f

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11a4344d600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17c93de9600000

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

#syz fix: RDMA/restrack: Protect from reentry to resource return path

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