BUG: unable to handle kernel paging request in kernfs_refresh_inode

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 12ceaf8864c2 infiniband: nes: Fix more direct skb list acc..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=16bcdfbd400000
kernel config: https://syzkaller.appspot.com/x/.config?x=dcbea7daf3ea3e3e
dashboard link: https://syzkaller.appspot.com/bug?extid=434afadebe061dac2d7b
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
CC: [gre...@linuxfoundation.org linux-...@vger.kernel.org
t...@kernel.org]

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+434afa...@syzkaller.appspotmail.com

PANIC: double fault, error_code: 0x0
CPU: 1 PID: -1978242712 Comm: Not tainted 4.20.0-rc1+ #289
BUG: unable to handle kernel paging request at ffff8801d9a18db8
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
PGD be01067 P4D be01067 PUD 1d9a8a063
BAD
Oops: 0009 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 8063 Comm: blkid Not tainted 4.20.0-rc1+ #289
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:kernfs_refresh_inode+0x43/0x4c0 fs/kernfs/inode.c:188
Code: ff 49 8d bd 98 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1
ea 03 80 3c 02 00 0f 85 df 03 00 00 49 8d bd 92 00 00 00 <49> 8b 9d 98 00
00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1
RSP: 0018:ffff88019010f5d0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff8801cd18f620 RCX: 0000000000000000
RDX: 1ffff1003b3431b7 RSI: ffffffff81f875ca RDI: ffff8801d9a18db2
RBP: ffff88019010f5f8 R08: fffffbfff12cfa21 R09: fffffbfff12cfa20
R10: ffff88019010f5f8 R11: ffffffff8967d107 R12: ffff8801cd18f620
R13: ffff8801d9a18d20 R14: 0000000000000000 R15: ffff8801cd18f622
FS: 00007f31addde740(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff8801d9a8a668 CR3: 00000001c2ed2000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
kernfs_iop_permission+0x70/0xb0 fs/kernfs/inode.c:302
do_inode_permission fs/namei.c:386 [inline]
inode_permission+0x35e/0x560 fs/namei.c:451
may_lookup fs/namei.c:1702 [inline]
link_path_walk.part.40+0xabd/0x1530 fs/namei.c:2084
link_path_walk fs/namei.c:2072 [inline]
path_openat+0x270/0x5150 fs/namei.c:3533
do_filp_open+0x255/0x380 fs/namei.c:3564
do_sys_open+0x568/0x700 fs/open.c:1063
__do_sys_open fs/open.c:1081 [inline]
__se_sys_open fs/open.c:1076 [inline]
__x64_sys_open+0x7e/0xc0 fs/open.c:1076
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f31ad6e6120
Code: 48 8b 15 1b 4d 2b 00 f7 d8 64 89 02 83 c8 ff c3 90 90 90 90 90 90 90
90 90 90 83 3d d5 a4 2b 00 00 75 10 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff
ff 73 31 c3 48 83 ec 08 e8 5e 8c 01 00 48 89 04 24
RSP: 002b:00007ffef6a720e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007ffef6a73130 RCX: 00007f31ad6e6120
RDX: 00007ffef6a72102 RSI: 0000000000000000 RDI: 00007ffef6a720f0
RBP: 0000000000000704 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffef6a741a8
R13: 0000000000000000 R14: 00007f31adbc7820 R15: 00007f31ad9bd2a2
Modules linked in:
CR2: ffff8801d9a18db8
---[ end trace a3b192a12f30b4ac ]---
RIP: 0010:kernfs_refresh_inode+0x43/0x4c0 fs/kernfs/inode.c:188
Code: ff 49 8d bd 98 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1
ea 03 80 3c 02 00 0f 85 df 03 00 00 49 8d bd 92 00 00 00 <49> 8b 9d 98 00
00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1
RSP: 0018:ffff88019010f5d0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff8801cd18f620 RCX: 0000000000000000
RDX: 1ffff1003b3431b7 RSI: ffffffff81f875ca RDI: ffff8801d9a18db2
RBP: ffff88019010f5f8 R08: fffffbfff12cfa21 R09: fffffbfff12cfa20
R10: ffff88019010f5f8 R11: ffffffff8967d107 R12: ffff8801cd18f620
R13: ffff8801d9a18d20 R14: 0000000000000000 R15: ffff8801cd18f622
FS: 00007f31addde740(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff8801d9a8a668 CR3: 00000001c2ed2000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.