WARNING in remove_proc_entry

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f8a27f9e27b Linux 4.19.211
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=177e9df2880000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=10a66d5b0eea6f260c3a
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/98c0bdb4abb3/disk-3f8a27f9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ea228ff02669/vmlinux-3f8a27f9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+10a66d...@syzkaller.appspotmail.com

name 'info'
WARNING: CPU: 1 PID: 19962 at fs/proc/generic.c:695 remove_proc_entry+0x205/0x3a0 fs/proc/generic.c:695
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 19962 Comm: syz-executor.5 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
panic+0x26a/0x50e kernel/panic.c:186
__warn.cold+0x20/0x5a kernel/panic.c:541
report_bug+0x262/0x2b0 lib/bug.c:183
fixup_bug arch/x86/kernel/traps.c:178 [inline]
fixup_bug arch/x86/kernel/traps.c:173 [inline]
do_error_trap+0x1d7/0x310 arch/x86/kernel/traps.c:296
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1038
RIP: 0010:remove_proc_entry+0x205/0x3a0 fs/proc/generic.c:695
Code: 1b 57 06 e8 9d 48 a0 ff eb a3 e8 96 48 a0 ff 48 c7 c7 e0 a0 06 8a e8 3a 1b 57 06 4c 89 e6 48 c7 c7 80 ed 76 88 e8 60 80 30 06 <0f> 0b eb d5 e8 72 48 a0 ff 4c 8b 64 24 50 48 b8 00 00 00 00 00 fc
RSP: 0018:ffff888091f6f898 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 1ffff110123edf15 RCX: 0000000000000000
RDX: 0000000000040000 RSI: ffffffff814dff01 RDI: ffffed10123edf05
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: ffffffff887c1c40
R13: dffffc0000000000 R14: ffff888094861668 R15: ffff888094861650
jbd2_stats_proc_exit fs/jbd2/journal.c:1119 [inline]
jbd2_journal_destroy+0x449/0x790 fs/jbd2/journal.c:1789
ext4_load_journal fs/ext4/super.c:4960 [inline]
ext4_fill_super+0xaacf/0xc850 fs/ext4/super.c:4295
mount_bdev+0x2fc/0x3b0 fs/super.c:1158
mount_fs+0xa3/0x310 fs/super.c:1261
vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
vfs_kern_mount fs/namespace.c:951 [inline]
do_new_mount fs/namespace.c:2492 [inline]
do_mount+0x115c/0x2f50 fs/namespace.c:2822
ksys_mount+0xcf/0x130 fs/namespace.c:3038
__do_sys_mount fs/namespace.c:3052 [inline]
__se_sys_mount fs/namespace.c:3049 [inline]
__x64_sys_mount+0xba/0x150 fs/namespace.c:3049
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f34137adada
Code: 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 b8 04 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3411d1ef88 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 00007f34137adada
RDX: 00000000200000c0 RSI: 0000000020000100 RDI: 00007f3411d1efe0
RBP: 00007f3411d1f020 R08: 00007f3411d1f020 R09: 00000000200000c0
R10: 0000000000000000 R11: 0000000000000202 R12: 00000000200000c0
R13: 0000000020000100 R14: 00007f3411d1efe0 R15: 0000000020000180
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 3f8a27f9e27b Linux 4.19.211
git tree: linux-4.19.y

console output: https://syzkaller.appspot.com/x/log.txt?x=1721c4ca880000

kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=10a66d5b0eea6f260c3a
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15e76b26880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14efee5e880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/98c0bdb4abb3/disk-3f8a27f9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ea228ff02669/vmlinux-3f8a27f9.xz

mounted in repro: https://storage.googleapis.com/syzbot-assets/49181382b961/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+10a66d...@syzkaller.appspotmail.com

R13: 00007ffe750e53e0 R14: 0000000000000014 R15: 00000000200003e0
JBD2: no valid journal superblock found
EXT4-fs (loop0): error loading journal
------------[ cut here ]------------
name 'info'
WARNING: CPU: 0 PID: 8171 at fs/proc/generic.c:695 remove_proc_entry+0x205/0x3a0 fs/proc/generic.c:695

Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 8171 Comm: syz-executor283 Not tainted 4.19.211-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
panic+0x26a/0x50e kernel/panic.c:186
__warn.cold+0x20/0x5a kernel/panic.c:541
report_bug+0x262/0x2b0 lib/bug.c:183
fixup_bug arch/x86/kernel/traps.c:178 [inline]
fixup_bug arch/x86/kernel/traps.c:173 [inline]
do_error_trap+0x1d7/0x310 arch/x86/kernel/traps.c:296
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1038
RIP: 0010:remove_proc_entry+0x205/0x3a0 fs/proc/generic.c:695
Code: 1b 57 06 e8 9d 48 a0 ff eb a3 e8 96 48 a0 ff 48 c7 c7 e0 a0 06 8a e8 3a 1b 57 06 4c 89 e6 48 c7 c7 80 ed 76 88 e8 60 80 30 06 <0f> 0b eb d5 e8 72 48 a0 ff 4c 8b 64 24 50 48 b8 00 00 00 00 00 fc

RSP: 0018:ffff88809d697898 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 1ffff11013ad2f15 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff814dff01 RDI: ffffed1013ad2f05

RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: ffffffff887c1c40

R13: dffffc0000000000 R14: ffff8880a5f5d4a8 R15: ffff8880a5f5d490

jbd2_stats_proc_exit fs/jbd2/journal.c:1119 [inline]
jbd2_journal_destroy+0x449/0x790 fs/jbd2/journal.c:1789
ext4_load_journal fs/ext4/super.c:4960 [inline]
ext4_fill_super+0xaacf/0xc850 fs/ext4/super.c:4295
mount_bdev+0x2fc/0x3b0 fs/super.c:1158
mount_fs+0xa3/0x310 fs/super.c:1261
vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
vfs_kern_mount fs/namespace.c:951 [inline]
do_new_mount fs/namespace.c:2492 [inline]
do_mount+0x115c/0x2f50 fs/namespace.c:2822
ksys_mount+0xcf/0x130 fs/namespace.c:3038
__do_sys_mount fs/namespace.c:3052 [inline]
__se_sys_mount fs/namespace.c:3049 [inline]
__x64_sys_mount+0xba/0x150 fs/namespace.c:3049
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe

RIP: 0033:0x7f26e16b03fa
Code: 48 c7 c2 c0 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 a8 00 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe750e5388 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f26e16b03fa
RDX: 00000000200000c0 RSI: 0000000020000100 RDI: 00007ffe750e53a0
RBP: 00007ffe750e53a0 R08: 00007ffe750e53e0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000005
R13: 00007ffe750e53e0 R14: 0000000000000014 R15: 00000000200003e0