general protection fault in locks_remove_flock

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: d881de30d29e Add linux-next specific files for 20181107
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1594d983400000
kernel config: https://syzkaller.appspot.com/x/.config?x=caa433e1c8778437
dashboard link: https://syzkaller.appspot.com/bug?extid=2400c924363a9a43d116
compiler: gcc (GCC) 8.0.1 20180413 (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+2400c9...@syzkaller.appspotmail.com

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 13218 Comm: syz-executor3 Not tainted 4.20.0-rc1-next-20181107+
#107
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:locks_remove_flock+0x216/0x350 fs/locks.c:2567
Code: 00 0f 85 3a 01 00 00 48 8b 5b 98 48 85 db 74 3a e8 1f 41 92 ff 48 8d
7b 08 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
85 17 01 00 00 48 8b 5b 08 48 85 db 74 0d e8 f2 40
RSP: 0018:ffff8801895a7880 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000041b58ab3 RCX: ffffffff81ed555d
RDX: 000000000836b157 RSI: ffffffff81ed5c71 RDI: 0000000041b58abb
RBP: ffff8801895a7a60 R08: ffff880194096140 R09: ffffed003b5c5b67
R10: ffffed003b5c5b67 R11: ffff8801dae2db3b R12: ffff8801cb266ac0
R13: ffff8801895a78f8 R14: 1ffff100312b4f13 R15: dffffc0000000000
FS: 0000000002927940(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000400200 CR3: 00000001bd0d5000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
locks_remove_file+0x148/0x5c0 fs/locks.c:2607
__fput+0x2f0/0xa70 fs/file_table.c:271
____fput+0x15/0x20 fs/file_table.c:312
task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x411021
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 34 19 00 00 c3 48
83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48
89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ffe309feb50 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000411021
RDX: 0000000000000000 RSI: 0000000000730420 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffe309fea70 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000001 R14: 000000000000010d R15: 0000000000000003
Modules linked in:
---[ end trace 69f886046d36502a ]---
RIP: 0010:locks_remove_flock+0x216/0x350 fs/locks.c:2567
kasan: CONFIG_KASAN_INLINE enabled
Code: 00 0f 85 3a 01 00 00 48 8b 5b 98 48 85 db 74 3a e8 1f 41 92 ff 48 8d
7b 08 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
85 17 01 00 00 48 8b 5b 08 48 85 db 74 0d e8 f2 40
kasan: GPF could be caused by NULL-ptr deref or user memory access
RSP: 0018:ffff8801895a7880 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000041b58ab3 RCX: ffffffff81ed555d
kasan: CONFIG_KASAN_INLINE enabled
RDX: 000000000836b157 RSI: ffffffff81ed5c71 RDI: 0000000041b58abb
RBP: ffff8801895a7a60 R08: ffff880194096140 R09: ffffed003b5c5b67
R10: ffffed003b5c5b67 R11: ffff8801dae2db3b R12: ffff8801cb266ac0
kasan: GPF could be caused by NULL-ptr deref or user memory access
R13: ffff8801895a78f8 R14: 1ffff100312b4f13 R15: dffffc0000000000
FS: 0000000002927940(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000072c000 CR3: 00000001bd0d5000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit: d881de30d29e Add linux-next specific files for 20181107
git tree: linux-next

console output: https://syzkaller.appspot.com/x/log.txt?x=10a0102b400000

kernel config: https://syzkaller.appspot.com/x/.config?x=caa433e1c8778437
dashboard link: https://syzkaller.appspot.com/bug?extid=2400c924363a9a43d116
compiler: gcc (GCC) 8.0.1 20180413 (experimental)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14b42f5b400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=151777e5400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+2400c9...@syzkaller.appspotmail.com

audit: type=1800 audit(1541602996.121:30): pid=5502 uid=0 auid=4294967295
ses=4294967295 subj==unconfined op=collect_data cause=failed(directio)
comm="startpar" name="rmnologin" dev="sda1" ino=2423 res=0

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN

CPU: 1 PID: 5657 Comm: syz-executor710 Not tainted

4.20.0-rc1-next-20181107+ #107
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:locks_remove_flock+0x216/0x350 fs/locks.c:2567
Code: 00 0f 85 3a 01 00 00 48 8b 5b 98 48 85 db 74 3a e8 1f 41 92 ff 48 8d
7b 08 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
85 17 01 00 00 48 8b 5b 08 48 85 db 74 0d e8 f2 40

RSP: 0018:ffff8801b9dc72c0 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 1ffff100373b8e89 RCX: ffffffff81ed555d
RDX: 03fffe2006e771d2 RSI: ffffffff81ed5c71 RDI: 1ffff100373b8e91
RBP: ffff8801b9dc74a0 R08: ffff8801b9dbc480 R09: ffffed003b5e5b67
R10: ffffed003b5e5b67 R11: ffff8801daf2db3b R12: ffff8801d88f9c80
R13: ffff8801b9dc7338 R14: 1ffff100373b8e5b R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 000000002001d000 CR3: 000000000946a000 CR4: 00000000001406e0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Call Trace:
locks_remove_file+0x148/0x5c0 fs/locks.c:2607
__fput+0x2f0/0xa70 fs/file_table.c:271
____fput+0x15/0x20 fs/file_table.c:312
task_work_run+0x1e8/0x2a0 kernel/task_work.c:113

exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x1ad1/0x26d0 kernel/exit.c:867
do_group_exit+0x177/0x440 kernel/exit.c:970
__do_sys_exit_group kernel/exit.c:981 [inline]
__se_sys_exit_group kernel/exit.c:979 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:979
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x43ede8
Code: Bad RIP value.
RSP: 002b:00007ffe7a46fe78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ede8
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00000000004beea8 R08: 00000000000000e7 R09: ffffffffffffffd0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000006d1180 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace a84b3ae501385451 ]---

RIP: 0010:locks_remove_flock+0x216/0x350 fs/locks.c:2567

Code: 00 0f 85 3a 01 00 00 48 8b 5b 98 48 85 db 74 3a e8 1f 41 92 ff 48 8d
7b 08 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
85 17 01 00 00 48 8b 5b 08 48 85 db 74 0d e8 f2 40

RSP: 0018:ffff8801b9dc72c0 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 1ffff100373b8e89 RCX: ffffffff81ed555d
RDX: 03fffe2006e771d2 RSI: ffffffff81ed5c71 RDI: 1ffff100373b8e91
RBP: ffff8801b9dc74a0 R08: ffff8801b9dbc480 R09: ffffed003b5e5b67
R10: ffffed003b5e5b67 R11: ffff8801daf2db3b R12: ffff8801d88f9c80
R13: ffff8801b9dc7338 R14: 1ffff100373b8e5b R15: dffffc0000000000
FS: 000000000229b880(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 000000000043edbe CR3: 000000000946a000 CR4: 00000000001406e0

[Dmitry Vyukov]

On Wed, Nov 7, 2018 at 7:09 AM, syzbot
<syzbot+2400c9...@syzkaller.appspotmail.com> wrote:
> syzbot has found a reproducer for the following crash on:
>
> HEAD commit: d881de30d29e Add linux-next specific files for 20181107
> git tree: linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=10a0102b400000
> kernel config: https://syzkaller.appspot.com/x/.config?x=caa433e1c8778437
> dashboard link: https://syzkaller.appspot.com/bug?extid=2400c924363a9a43d116
> compiler: gcc (GCC) 8.0.1 20180413 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14b42f5b400000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=151777e5400000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+2400c9...@syzkaller.appspotmail.com

Assuming this is another manifestation of the following report.

#syz dup: KASAN: use-after-free Read in locks_delete_block

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