Message-ID: <CANp29Y6S=qD8-j869gHcNYM3ArXs03BxYBEB0c=Zb9mJvDGCCA@mail.gmail.com>
Date: Fri, 16 Aug 2024 18:43:38 +0200
From: Aleksandr Nogikh <nogikh@...gle.com>
To: Kent Overstreet <kent.overstreet@...ux.dev>
Cc: Dmitry Vyukov <dvyukov@...gle.com>, linux-bcachefs@...r.kernel.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [bcachefs?] WARNING in discard_new_inode

On Fri, Aug 16, 2024 at 6:30 PM Kent Overstreet
<kent.overstreet@...ux.dev> wrote:
>
> On Fri, Aug 16, 2024 at 02:50:23AM GMT, syzbot wrote:
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    d7a5aa4b3c00 Merge tag 'perf-tools-fixes-for-v6.11-2024-08..
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=131e27c5980000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=7229118d88b4a71b
> > dashboard link: https://syzkaller.appspot.com/bug?extid=95e40eae71609e40d851
> > compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=150be3c5980000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=165c93cb980000
> >
> > Downloadable assets:
> > disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-d7a5aa4b.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/af15738cca6c/vmlinux-d7a5aa4b.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/62dacb1384ee/bzImage-d7a5aa4b.xz
> > mounted in repro: https://storage.googleapis.com/syzbot-assets/92de1b01cc1a/mount_0.gz
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+95e40eae71609e40d851@...kaller.appspotmail.com
> >
> > R13: 00007f7d2a233210 R14: 0000000000000001 R15: 0032656c69662f2e
> >  </TASK>
>
> Dmitry, this bug has been fixed upstream, and I've been seeing others
> where syzbot appears to be generating reports for bugs that have been
> fixed (e.g. BUG() in bch2_fs_journal_stop() long after that was changed
> to a warning).
>
> I don't know what's going on, but the report appears to be in error.

Did those fixes already reach the latest torvalds?
I've just tried to run the C reproducer from the report on
d7a5aa4b3c00 several times and it eventually did crash the kernel.

[   42.746251][ T5239] ------------[ cut here ]------------
[   42.747210][ T5239] WARNING: CPU: 0 PID: 5239 at fs/inode.c:1143
discard_new_inode+0x217/0x2a0
[   42.748401][ T5239] Modules linked in:
[   42.748948][ T5239] CPU: 0 UID: 0 PID: 5239 Comm: repro Not tainted
6.11.0-rc3-syzkaller-00156-gd7a5aa4b3c00 #0
[   42.750331][ T5239] Hardware name: QEMU Standard PC (Q35 + ICH9,
2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[   42.751806][ T5239] RIP: 0010:discard_new_inode+0x217/0x2a0

--
Aleksandr

>
> > ------------[ cut here ]------------
> > WARNING: CPU: 0 PID: 5116 at fs/inode.c:1143 discard_new_inode+0x217/0x2a0 fs/inode.c:1143
> > Modules linked in:
> > CPU: 0 UID: 0 PID: 5116 Comm: syz-executor345 Not tainted 6.11.0-rc3-syzkaller-00156-gd7a5aa4b3c00 #0
> > Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
> > RIP: 0010:discard_new_inode+0x217/0x2a0 fs/inode.c:1143
> > Code: 00 e8 ad d7 59 ff 4c 89 f7 e8 e5 98 ad 09 4c 89 e7 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d e9 9f 00 00 00 e8 ba 6e 80 ff 90 <0f> 0b 90 42 80 3c 2b 00 75 ae eb b4 44 89 e1 80 e1 07 fe c1 38 c1
> > RSP: 0018:ffffc90002d1f1e0 EFLAGS: 00010293
> > RAX: ffffffff82131c36 RBX: 1ffff110078521f2 RCX: ffff888018a94880
> > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
> > RBP: 0000000000000000 R08: ffffffff82131bdd R09: fffff520005a3e2c
> > R10: dffffc0000000000 R11: fffff520005a3e2c R12: ffff88803c290ec0
> > R13: dffffc0000000000 R14: ffff88803c290f40 R15: ffff88803c290f90
> > FS:  00007f7d2a2336c0(0000) GS:ffff888020800000(0000) knlGS:0000000000000000
> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00007f4c62ac2440 CR3: 000000003a4be000 CR4: 0000000000350ef0
> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > Call Trace:
> >  <TASK>
> >  bch2_inode_insert+0x35b/0x3d0 fs/bcachefs/fs.c:203
> >  bch2_lookup_trans fs/bcachefs/fs.c:465 [inline]
> >  bch2_lookup+0x1014/0x16c0 fs/bcachefs/fs.c:483
> >  lookup_open fs/namei.c:3556 [inline]
> >  open_last_lookups fs/namei.c:3647 [inline]
> >  path_openat+0x11cc/0x3470 fs/namei.c:3883
> >  do_filp_open+0x235/0x490 fs/namei.c:3913
> >  do_sys_openat2+0x13e/0x1d0 fs/open.c:1416
> >  do_sys_open fs/open.c:1431 [inline]
> >  __do_sys_openat fs/open.c:1447 [inline]
> >  __se_sys_openat fs/open.c:1442 [inline]
> >  __x64_sys_openat+0x247/0x2a0 fs/open.c:1442
> >  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> >  do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
> >  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> > RIP: 0033:0x7f7d2a2861a9
> > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 71 1d 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
> > RSP: 002b:00007f7d2a233208 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
> > RAX: ffffffffffffffda RBX: 00007f7d2a30c6a8 RCX: 00007f7d2a2861a9
> > RDX: 0000000000000000 RSI: 0000000020004280 RDI: ffffffffffffff9c
> > RBP: 00007f7d2a30c6a0 R08: 00007f7d2a232fa7 R09: 0000000000000038
> > R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7d2a2d9090
> > R13: 00007f7d2a233210 R14: 0000000000000001 R15: 0032656c69662f2e
> >  </TASK>
> >
> >
> > ---
> > This report is generated by a bot. It may contain errors.
> > See https://goo.gl/tpsmEJ for more information about syzbot.
> > syzbot engineers can be reached at syzkaller@...glegroups.com.
> >
> > syzbot will keep track of this issue. See:
> > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> >
> > If the report is already addressed, let syzbot know by replying with:
> > #syz fix: exact-commit-title
> >
> > If you want syzbot to run the reproducer, reply with:
> > #syz test: git://repo/address.git branch-or-commit-hash
> > If you attach or paste a git patch, syzbot will apply it before testing.
> >
> > If you want to overwrite report's subsystems, reply with:
> > #syz set subsystems: new-subsystem
> > (See the list of subsystem names on the web dashboard)
> >
> > If the report is a duplicate of another one, reply with:
> > #syz dup: exact-subject-of-another-report
> >
> > If you want to undo deduplication, reply with:
> > #syz undup
>
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