BUG: unable to handle kernel NULL pointer dereference in qlist_free_all (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3c8c2309 Linux 4.19.190
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=12705a65d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=d3c2572d41264a3d
dashboard link: https://syzkaller.appspot.com/bug?extid=dcdc3ad90e7e39bc0b5a

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dcdc3a...@syzkaller.appspotmail.com

BUG: unable to handle kernel NULL pointer dereference at 00000000000000fc
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 4696 Comm: systemd-udevd Not tainted 4.19.190-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:qlink_to_object mm/kasan/quarantine.c:136 [inline]
RIP: 0010:qlink_free mm/kasan/quarantine.c:141 [inline]
RIP: 0010:qlist_free_all+0x28/0x140 mm/kasan/quarantine.c:166
Code: 90 90 41 57 41 56 41 55 41 54 55 53 48 8b 1f 48 85 db 0f 84 08 01 00 00 48 89 f5 49 89 fd 48 85 ed 49 89 ee 0f 84 8b 00 00 00 <49> 63 86 fc 00 00 00 4c 8b 23 48 29 c3 48 83 3d b3 50 59 08 00 0f
RSP: 0018:ffff88809ce879c8 EFLAGS: 00010246
RAX: ffffea0000000000 RBX: ffff888000000000 RCX: ffffea0000000007
RDX: 0000000000000000 RSI: ffffffff812b5e9a RDI: 0000000000000007
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000007 R11: 0000000000000000 R12: ffff888000000000
R13: ffff88809ce87a00 R14: 0000000000000000 R15: 0000000000000282
FS: 00007f25739ec8c0(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000fc CR3: 000000009c981000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
quarantine_reduce+0x1a9/0x230 mm/kasan/quarantine.c:259
kasan_kmalloc+0xa2/0x160 mm/kasan/kasan.c:538
slab_post_alloc_hook mm/slab.h:445 [inline]
slab_alloc mm/slab.c:3397 [inline]
kmem_cache_alloc+0x110/0x370 mm/slab.c:3557
getname_flags+0xce/0x590 fs/namei.c:140
user_path_at_empty+0x2a/0x50 fs/namei.c:2609
user_path_at include/linux/namei.h:57 [inline]
vfs_statx+0x113/0x210 fs/stat.c:185
vfs_lstat include/linux/fs.h:3137 [inline]
__do_sys_newlstat fs/stat.c:350 [inline]
__se_sys_newlstat+0x96/0x120 fs/stat.c:344
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f257285e335
Code: 69 db 2b 00 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 83 ff 01 48 89 f0 77 30 48 89 c7 48 89 d6 b8 06 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 03 f3 c3 90 48 8b 15 31 db 2b 00 f7 d8 64 89
RSP: 002b:00007ffe1c8ef6d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000006
RAX: ffffffffffffffda RBX: 00005652b65468b0 RCX: 00007f257285e335
RDX: 00007ffe1c8ef710 RSI: 00007ffe1c8ef710 RDI: 00005652b65458b0
RBP: 00007ffe1c8ef7d0 R08: 00007f2572b1d1b8 R09: 0000000000001010
R10: 0000000000000100 R11: 0000000000000246 R12: 00005652b65458b0
R13: 00005652b65458ca R14: 00005652b6554fe5 R15: 00005652b6554fea
Modules linked in:
CR2: 00000000000000fc
audit: type=1804 audit(1621599717.626:4431): pid=7657 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.4" name="/root/syzkaller-testdir658732563/syzkaller.cFG3nK/2592/cgroup.controllers" dev="sda1" ino=15530 res=1
---[ end trace 704cf1ec12eb6f0e ]---
RIP: 0010:qlink_to_object mm/kasan/quarantine.c:136 [inline]
RIP: 0010:qlink_free mm/kasan/quarantine.c:141 [inline]
RIP: 0010:qlist_free_all+0x28/0x140 mm/kasan/quarantine.c:166
Code: 90 90 41 57 41 56 41 55 41 54 55 53 48 8b 1f 48 85 db 0f 84 08 01 00 00 48 89 f5 49 89 fd 48 85 ed 49 89 ee 0f 84 8b 00 00 00 <49> 63 86 fc 00 00 00 4c 8b 23 48 29 c3 48 83 3d b3 50 59 08 00 0f
RSP: 0018:ffff88809ce879c8 EFLAGS: 00010246
RAX: ffffea0000000000 RBX: ffff888000000000 RCX: ffffea0000000007
RDX: 0000000000000000 RSI: ffffffff812b5e9a RDI: 0000000000000007
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000007 R11: 0000000000000000 R12: ffff888000000000
audit: type=1804 audit(1621599718.086:4432): pid=7686 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.4" name="/root/syzkaller-testdir658732563/syzkaller.cFG3nK/2593/cgroup.controllers" dev="sda1" ino=15530 res=1
R13: ffff88809ce87a00 R14: 0000000000000000 R15: 0000000000000282
FS: 00007f25739ec8c0(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
audit: type=1804 audit(1621599718.136:4433): pid=7688 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir835264348/syzkaller.uP68Qh/2615/cgroup.controllers" dev="sda1" ino=15538 res=1
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000002f6d708 CR3: 000000009c981000 CR4: 00000000001426e0
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.