invalid opcode in do_journal_end

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cb690f5238d7 Merge tag 'for-5.16/drivers-2021-11-09' of gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12db95c1b00000
kernel config: https://syzkaller.appspot.com/x/.config?x=2897a869f0607967
dashboard link: https://syzkaller.appspot.com/bug?extid=5591d8fc6ecfa5f63f9e
compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.2
CC: [ja...@suse.cz linux-...@vger.kernel.org paskr...@gmail.com reiserf...@vger.kernel.org tian...@hisilicon.com]

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+5591d8...@syzkaller.appspotmail.com

invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 10214 Comm: syz-executor.3 Not tainted 5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:check_journal_end fs/reiserfs/journal.c:3642 [inline]
RIP: 0010:do_journal_end+0x459b/0x4610 fs/reiserfs/journal.c:4038
Code: 7c 24 18 48 c7 c6 e0 35 86 8a 48 c7 c2 e4 98 3f 8c 48 c7 c1 20 36 86 8a 41 89 e8 41 89 d9 31 c0 e8 ea fb fb ff e8 95 d4 65 ff <0f> 0b e8 8e d4 65 ff e8 39 9e b1 ff 48 8b 7c 24 18 48 c7 c6 e0 52
RSP: 0018:ffffc90002bef6b8 EFLAGS: 00010246
RAX: ffffffff821e77db RBX: ffffc90002d89048 RCX: 0000000000040000
RDX: ffffc9000fbbc000 RSI: 000000000003ffff RDI: 0000000000040000
RBP: 1ffff920005b1209 R08: ffffffff821e3835 R09: fffff520005b120c
R10: fffff520005b120c R11: 0000000000000000 R12: ffffc90002d89000
R13: 1ffff920005b120b R14: ffffc90002d89058 R15: 0000000000000000
FS: 00007f7469033700(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc30d140058 CR3: 0000000092a91000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<TASK>
reiserfs_fill_super+0x3100/0x37e0 fs/reiserfs/super.c:2166
mount_bdev+0x26c/0x3a0 fs/super.c:1370
legacy_get_tree+0xea/0x180 fs/fs_context.c:610
vfs_get_tree+0x86/0x270 fs/super.c:1500
do_new_mount fs/namespace.c:2988 [inline]
path_mount+0x1986/0x2c30 fs/namespace.c:3318
do_mount fs/namespace.c:3331 [inline]
__do_sys_mount fs/namespace.c:3539 [inline]
__se_sys_mount+0x308/0x3c0 fs/namespace.c:3516
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f746bae001a
Code: 48 c7 c2 bc 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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7469032fa8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 00007f746bae001a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f7469033000
RBP: 00007f7469033040 R08: 00007f7469033040 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000020000000
R13: 0000000020000100 R14: 00007f7469033000 R15: 0000000020011500
</TASK>
Modules linked in:
---[ end trace c08200142ae8b509 ]---
RIP: 0010:check_journal_end fs/reiserfs/journal.c:3642 [inline]
RIP: 0010:do_journal_end+0x459b/0x4610 fs/reiserfs/journal.c:4038
Code: 7c 24 18 48 c7 c6 e0 35 86 8a 48 c7 c2 e4 98 3f 8c 48 c7 c1 20 36 86 8a 41 89 e8 41 89 d9 31 c0 e8 ea fb fb ff e8 95 d4 65 ff <0f> 0b e8 8e d4 65 ff e8 39 9e b1 ff 48 8b 7c 24 18 48 c7 c6 e0 52
RSP: 0018:ffffc90002bef6b8 EFLAGS: 00010246
RAX: ffffffff821e77db RBX: ffffc90002d89048 RCX: 0000000000040000
RDX: ffffc9000fbbc000 RSI: 000000000003ffff RDI: 0000000000040000
RBP: 1ffff920005b1209 R08: ffffffff821e3835 R09: fffff520005b120c
R10: fffff520005b120c R11: 0000000000000000 R12: ffffc90002d89000
R13: 1ffff920005b120b R14: ffffc90002d89058 R15: 0000000000000000
FS: 00007f7469033700(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc30d140058 CR3: 0000000092a91000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600


---
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[Dmitry Vyukov]

On Wed, 10 Nov 2021 at 18:01, syzbot
<syzbot+5591d8...@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: cb690f5238d7 Merge tag 'for-5.16/drivers-2021-11-09' of gi..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=12db95c1b00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=2897a869f0607967
> dashboard link: https://syzkaller.appspot.com/bug?extid=5591d8fc6ecfa5f63f9e
> compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.2
> CC: [ja...@suse.cz linux-...@vger.kernel.org paskr...@gmail.com reiserf...@vger.kernel.org tian...@hisilicon.com]
>
> 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+5591d8...@syzkaller.appspotmail.com
>
> invalid opcode: 0000 [#1] PREEMPT SMP KASAN
> CPU: 1 PID: 10214 Comm: syz-executor.3 Not tainted 5.15.0-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:check_journal_end fs/reiserfs/journal.c:3642 [inline]
> RIP: 0010:do_journal_end+0x459b/0x4610 fs/reiserfs/journal.c:4038
> Code: 7c 24 18 48 c7 c6 e0 35 86 8a 48 c7 c2 e4 98 3f 8c 48 c7 c1 20 36 86 8a 41 89 e8 41 89 d9 31 c0 e8 ea fb fb ff e8 95 d4 65 ff <0f> 0b e8 8e d4 65 ff e8 39 9e b1 ff 48 8b 7c 24 18 48 c7 c6 e0 52

+Aleksandr, why didn't we provide code disassembly for this one?
It says "invalid opcode", so I actually wanted to look at the code disasm.

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[Marco Elver]

On Wed, 10 Nov 2021 at 18:41, 'Dmitry Vyukov' via
syzkaller-upstream-moderation

<syzkaller-upst...@googlegroups.com> wrote:
>
> On Wed, 10 Nov 2021 at 18:01, syzbot
> <syzbot+5591d8...@syzkaller.appspotmail.com> wrote:
> >
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit: cb690f5238d7 Merge tag 'for-5.16/drivers-2021-11-09' of gi..
> > git tree: upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=12db95c1b00000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=2897a869f0607967
> > dashboard link: https://syzkaller.appspot.com/bug?extid=5591d8fc6ecfa5f63f9e
> > compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.2
> > CC: [ja...@suse.cz linux-...@vger.kernel.org paskr...@gmail.com reiserf...@vger.kernel.org tian...@hisilicon.com]
> >
> > 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+5591d8...@syzkaller.appspotmail.com
> >
> > invalid opcode: 0000 [#1] PREEMPT SMP KASAN
> > CPU: 1 PID: 10214 Comm: syz-executor.3 Not tainted 5.15.0-syzkaller #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> > RIP: 0010:check_journal_end fs/reiserfs/journal.c:3642 [inline]
> > RIP: 0010:do_journal_end+0x459b/0x4610 fs/reiserfs/journal.c:4038
> > Code: 7c 24 18 48 c7 c6 e0 35 86 8a 48 c7 c2 e4 98 3f 8c 48 c7 c1 20 36 86 8a 41 89 e8 41 89 d9 31 c0 e8 ea fb fb ff e8 95 d4 65 ff <0f> 0b e8 8e d4 65 ff e8 39 9e b1 ff 48 8b 7c 24 18 48 c7 c6 e0 52
>
> +Aleksandr, why didn't we provide code disassembly for this one?
> It says "invalid opcode", so I actually wanted to look at the code disasm.

I think something else went wrong. "0f 0b" is ud2, and journal.c:3642
is "BUG_ON(journal->j_len == 0)". Did BUG_ON() break?

[Marco Elver]

On Wed, 10 Nov 2021 at 19:19, Marco Elver <el...@google.com> wrote:
>
> On Wed, 10 Nov 2021 at 18:41, 'Dmitry Vyukov' via
> syzkaller-upstream-moderation
> <syzkaller-upst...@googlegroups.com> wrote:
> >
> > On Wed, 10 Nov 2021 at 18:01, syzbot
> > <syzbot+5591d8...@syzkaller.appspotmail.com> wrote:
> > >
> > > Hello,
> > >
> > > syzbot found the following issue on:
> > >
> > > HEAD commit: cb690f5238d7 Merge tag 'for-5.16/drivers-2021-11-09' of gi..
> > > git tree: upstream
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=12db95c1b00000
> > > kernel config: https://syzkaller.appspot.com/x/.config?x=2897a869f0607967
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=5591d8fc6ecfa5f63f9e
> > > compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.2
> > > CC: [ja...@suse.cz linux-...@vger.kernel.org paskr...@gmail.com reiserf...@vger.kernel.org tian...@hisilicon.com]
> > >
> > > 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+5591d8...@syzkaller.appspotmail.com
> > >

There should be a "kernel BUG at" line here. I think it was somehow
cut, which led to this report.

I checked and the BUG() format between 5.15 and what's in 5.16 now is
identical. It's still:

[ 0.286769] ------------[ cut here ]------------
[ 0.287357] kernel BUG at foo/bar.c:1234!
[ 0.287751] invalid opcode: 0000 [#1] PREEMPT SMP PTI

So the only explanation is that it got lost. I would probably mark
this as invalid and hope that syzbot finds it again.

[syzbot]

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