general protection fault in qlist_free_all (4)

[syzbot]

Hello,

syzbot hit the following crash on upstream commit
0b412605ef5f5c64b31f19e2910b1d5eba9929c3 (Thu Mar 29 01:07:23 2018 +0000)
Merge tag 'drm-fixes-for-v4.16-rc8' of
git://people.freedesktop.org/~airlied/linux
syzbot dashboard link:
https://syzkaller.appspot.com/bug?extid=ba1d1ac3385a34685c6d

So far this crash happened 4 times on net-next, upstream.
Unfortunately, I don't have any reproducer for this crash yet.
Raw console output:
https://syzkaller.appspot.com/x/log.txt?id=5074439628652544
Kernel config:
https://syzkaller.appspot.com/x/.config?id=-8440362230543204781
compiler: gcc (GCC) 7.1.1 20170620
CC: [adilger...@dilger.ca linux...@vger.kernel.org
linux-...@vger.kernel.org ty...@mit.edu]

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Reported-by: syzbot+ba1d1a...@syzkaller.appspotmail.com
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kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 12870 Comm: syz-executor5 Not tainted 4.16.0-rc7+ #5
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:virt_to_head_page include/linux/mm.h:615 [inline]
RIP: 0010:qlink_to_cache mm/kasan/quarantine.c:127 [inline]
RIP: 0010:qlist_free_all+0x12b/0x160 mm/kasan/quarantine.c:163
RSP: 0018:ffff8801b3f0f428 EFLAGS: 00010203
RAX: ff020601c7a79d80 RBX: 0000000000000282 RCX: ffffea0000000000
RDX: 03fbf3f8071e9e40 RSI: ffff8801c633a908 RDI: 0000000000000282
RBP: ffff8801b3f0f460 R08: 1ffff100367e1e53 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ff020601c7a79d80 R15: ffffffff87acabe0
FS: 0000000002231940(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004b9baf CR3: 00000001c4cd3005 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
quarantine_reduce+0x141/0x170 mm/kasan/quarantine.c:259
kasan_kmalloc+0xca/0xe0 mm/kasan/kasan.c:537
kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
slab_post_alloc_hook mm/slab.h:443 [inline]
slab_alloc mm/slab.c:3380 [inline]
kmem_cache_alloc+0x11b/0x760 mm/slab.c:3540
ext4_alloc_inode+0xc1/0x7e0 fs/ext4/super.c:968
alloc_inode+0x65/0x180 fs/inode.c:209
new_inode_pseudo+0x69/0x190 fs/inode.c:890
new_inode+0x1c/0x40 fs/inode.c:919
__ext4_new_inode+0x3a0/0x4e80 fs/ext4/ialloc.c:859
ext4_symlink+0x41e/0x1060 fs/ext4/namei.c:3094
vfs_symlink+0x323/0x560 fs/namei.c:4105
SYSC_symlinkat fs/namei.c:4132 [inline]
SyS_symlinkat fs/namei.c:4112 [inline]
SYSC_symlink fs/namei.c:4145 [inline]
SyS_symlink+0x1d2/0x240 fs/namei.c:4143
do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x454607
RSP: 002b:00007ffe337395b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 00000000000000f9 RCX: 0000000000454607
RDX: 0000000000000000 RSI: 00000000004b9bb8 RDI: 00007ffe3373a2f0
RBP: 00007ffe33739c60 R08: 0000000000000000 R09: 0000000002231940
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000013 R14: 0000000000000000 R15: 0000000000001380
Code: 00 00 00 80 48 01 c2 72 44 48 b9 00 00 00 80 ff 77 00 00 48 01 ca 48
b9 00 00 00 00 00 ea ff ff 48 c1 ea 0c 48 c1 e2 06 48 01 ca <48> 8b 4a 20
48 8d 71 ff 83 e1 01 48 0f 45 d6 4c 8b 6a 30 e9 f4
RIP: virt_to_head_page include/linux/mm.h:615 [inline] RSP: ffff8801b3f0f428
RIP: qlink_to_cache mm/kasan/quarantine.c:127 [inline] RSP: ffff8801b3f0f428
RIP: qlist_free_all+0x12b/0x160 mm/kasan/quarantine.c:163 RSP:
ffff8801b3f0f428
---[ end trace 0609162322ee12fa ]---


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[syzbot]

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