linux-kernel - Re: [syzbot] [bcachefs?] kernel BUG in vfs_get

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Message-ID: <66f33aad.050a0220.457fc.0030.GAE@google.com>
Date: Tue, 24 Sep 2024 15:18:21 -0700
From: syzbot <syzbot+c0360e8367d6d8d04a66@...kaller.appspotmail.com>
To: brauner@...nel.org, jack@...e.cz, jfs-discussion@...ts.sourceforge.net, 
	kent.overstreet@...ux.dev, linux-bcachefs@...r.kernel.org, 
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, 
	shaggy@...nel.org, syzkaller-bugs@...glegroups.com, viro@...iv.linux.org.uk
Subject: Re: [syzbot] [bcachefs?] kernel BUG in vfs_get_tree

syzbot has found a reproducer for the following issue on:

HEAD commit:    abf2050f51fd Merge tag 'media/v6.12-1' of git://git.kernel..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11f08a80580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=bc30a30374b0753
dashboard link: https://syzkaller.appspot.com/bug?extid=c0360e8367d6d8d04a66
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=15fad2a9980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17b7b107980000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-abf2050f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2179ebeade58/vmlinux-abf2050f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f05289b5cf7c/bzImage-abf2050f.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/326532b68b88/mount_1.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c0360e8367d6d8d04a66@...kaller.appspotmail.com

bcachefs: bch2_fs_get_tree() error: EPERM
Filesystem bcachefs get_tree() didn't set fc->root, returned 1
------------[ cut here ]------------
kernel BUG at fs/super.c:1810!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5200 Comm: syz-executor203 Not tainted 6.11.0-syzkaller-09959-gabf2050f51fd #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:vfs_get_tree+0x29f/0x2b0 fs/super.c:1810
Code: 1e 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 14 c4 ec ff 48 8b 33 48 c7 c7 20 d4 18 8c 44 89 e2 e8 22 b3 ae 09 90 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 90 90 90 90 90
RSP: 0018:ffffc9000b457d08 EFLAGS: 00010246
RAX: 000000000000003e RBX: ffffffff8ef58520 RCX: 12995cb9c2040600
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 1ffff11008249016 R08: ffffffff81746c8c R09: 1ffff11003f8519a
R10: dffffc0000000000 R11: ffffed1003f8519b R12: 0000000000000001
R13: dffffc0000000000 R14: ffff888041248098 R15: ffff8880412480b0
FS:  0000555567b69480(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555567b72918 CR3: 000000004ebe6000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 do_new_mount+0x2be/0xb40 fs/namespace.c:3507
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4055 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4032
 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: 0033:0x7ff4a950680a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 7e 09 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007ffdb635bea8 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffdb635bec0 RCX: 00007ff4a950680a
RDX: 0000000020005d80 RSI: 0000000020005dc0 RDI: 00007ffdb635bec0
RBP: 0000000000000004 R08: 00007ffdb635bf00 R09: 0000000000005dc5
R10: 0000000000000000 R11: 0000000000000282 R12: 0000000000000000
R13: 00007ffdb635bf00 R14: 0000000000000003 R15: 0000000001000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:vfs_get_tree+0x29f/0x2b0 fs/super.c:1810
Code: 1e 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 14 c4 ec ff 48 8b 33 48 c7 c7 20 d4 18 8c 44 89 e2 e8 22 b3 ae 09 90 <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 90 90 90 90 90
RSP: 0018:ffffc9000b457d08 EFLAGS: 00010246
RAX: 000000000000003e RBX: ffffffff8ef58520 RCX: 12995cb9c2040600
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 1ffff11008249016 R08: ffffffff81746c8c R09: 1ffff11003f8519a
R10: dffffc0000000000 R11: ffffed1003f8519b R12: 0000000000000001
R13: dffffc0000000000 R14: ffff888041248098 R15: ffff8880412480b0
FS:  0000555567b69480(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff4a1141000 CR3: 000000004ebe6000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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.