general protection fault in sysfs_kf_seq_show

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 399849e4 Linux 4.19.131
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14df5233100000
kernel config: https://syzkaller.appspot.com/x/.config?x=eada6d424d8bae1d
dashboard link: https://syzkaller.appspot.com/bug?extid=df3ae2a342832682ed0c
compiler: gcc (GCC) 10.1.0-syz 20200507

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+df3ae2...@syzkaller.appspotmail.com

EXT4-fs (sda1): re-mounted. Opts:
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: 26678 Comm: systemd-udevd Not tainted 4.19.131-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:sysfs_kf_seq_show+0x187/0x400 fs/sysfs/file.c:60
Code: 8f 01 00 00 e8 8a 5d 9d ff ba 00 10 00 00 31 f6 4c 89 ff e8 cb 6b d3 ff 48 8b 14 24 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 09 02 00 00 48 8b 04 24 4c 8b 20 4d 85 e4 0f 84
RSP: 0018:ffff8881ecc37b80 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff8880a7b6b000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8881fb159380
RBP: 0000000000001000 R08: 0000000000000001 R09: ffff8881fb158380
R10: ffff8881fb15937f R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000001000 R14: ffff8880821f6080 R15: ffff8881fb158380
FS: 00007fc22f8f48c0(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004ee8b0 CR3: 0000000089bc0000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 00000000000058a2
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
seq_read+0x4be/0x1160 fs/seq_file.c:229
kernfs_fop_read+0xe9/0x550 fs/kernfs/file.c:252
__vfs_read+0xf7/0x750 fs/read_write.c:416
vfs_read+0x194/0x3c0 fs/read_write.c:452
ksys_read+0x12b/0x2a0 fs/read_write.c:579
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fc22e767910
Code: b6 fe ff ff 48 8d 3d 0f be 08 00 48 83 ec 08 e8 06 db 01 00 66 0f 1f 44 00 00 83 3d f9 2d 2c 00 00 75 10 b8 00 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 de 9b 01 00 48 89 04 24
RSP: 002b:00007ffe1bd51648 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00005647ba740570 RCX: 00007fc22e767910
RDX: 0000000000001000 RSI: 00005647ba743c00 RDI: 0000000000000007
RBP: 00007fc22ea22440 R08: 00007fc22ea261d8 R09: 0000000000001010
R10: 00005647ba740570 R11: 0000000000000246 R12: 0000000000001000
R13: 0000000000000d68 R14: 00005647ba743c00 R15: 00007fc22ea21900
Modules linked in:
---[ end trace 4adccab908dd1738 ]---
RIP: 0010:sysfs_kf_seq_show+0x187/0x400 fs/sysfs/file.c:60
Code: 8f 01 00 00 e8 8a 5d 9d ff ba 00 10 00 00 31 f6 4c 89 ff e8 cb 6b d3 ff 48 8b 14 24 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 09 02 00 00 48 8b 04 24 4c 8b 20 4d 85 e4 0f 84
RSP: 0018:ffff8881ecc37b80 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff8880a7b6b000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8881fb159380
RBP: 0000000000001000 R08: 0000000000000001 R09: ffff8881fb158380
R10: ffff8881fb15937f R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000001000 R14: ffff8880821f6080 R15: ffff8881fb158380
FS: 00007fc22f8f48c0(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004ee8b0 CR3: 0000000089bc0000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 00000000000058a2
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.