Re: [syzbot] [btrfs?] general protection fault in btrfs_orphan_cleanup

syzbot
2023-04-30T06:42:43Z

syzbot has found a reproducer for the following issue on:

HEAD commit: 1ae78a14516b Merge tag '6.4-rc-ksmbd-server-fixes' of git:..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1795c2f7c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=50dff7d7b2557ef1
dashboard link: https://syzkaller.appspot.com/bug?extid=2e15a1e4284bf8517741
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1255f594280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=165b28f8280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4818953c9914/disk-1ae78a14.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a78b3bf3e929/vmlinux-1ae78a14.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dae163980240/bzImage-1ae78a14.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/dd0e91b2ac87/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2e15a1e4284bf8517741@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc000000001a: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000000d0-0x00000000000000d7]
CPU: 0 PID: 5860 Comm: syz-executor269 Not tainted 6.3.0-syzkaller-11301-g1ae78a14516b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
RIP: 0010:iput+0x40/0x8f0 fs/inode.c:1763
Code: 06 2a 91 ff 48 85 ed 0f 84 56 03 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 9d d8 00 00 00 48 89 d9 48 c1 e9 03 48 89 4c 24 08 <80> 3c 01 00 74 08 48 89 df e8 f2 f4 e8 ff 48 89 1c 24 48 8b 1b 48
RSP: 0018:ffffc9000aa87a10 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 00000000000000d6 RCX: 000000000000001a
RDX: 0000000000000000 RSI: 0000000000000004 RDI: fffffffffffffffe
RBP: fffffffffffffffe R08: dffffc0000000000 R09: ffffed100dab82ef
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88806e6e0000
R13: fffffffffffffffc R14: 00000000fffffffe R15: dffffc0000000000
FS: 00007fbc4e794700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbc55c5d908 CR3: 0000000071785000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
btrfs_orphan_cleanup+0xa55/0xcf0 fs/btrfs/inode.c:3629
create_snapshot+0x520/0x7e0 fs/btrfs/ioctl.c:852
btrfs_mksubvol+0x5d0/0x750 fs/btrfs/ioctl.c:994
btrfs_mksnapshot+0xb5/0xf0 fs/btrfs/ioctl.c:1040
__btrfs_ioctl_snap_create+0x338/0x450 fs/btrfs/ioctl.c:1293
btrfs_ioctl_snap_create+0x136/0x190 fs/btrfs/ioctl.c:1320
btrfs_ioctl+0xbbc/0xd40
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fbc55c0cda9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 d1 15 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fbc4e7942f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fbc55c987f0 RCX: 00007fbc55c0cda9
RDX: 0000000020001380 RSI: 0000000050009401 RDI: 0000000000000007
RBP: 00007fbc55c645ec R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0030656c69662f2e
R13: 00007fbc55c635f0 R14: 697265765f666572 R15: 00007fbc55c987f8
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:iput+0x40/0x8f0 fs/inode.c:1763
Code: 06 2a 91 ff 48 85 ed 0f 84 56 03 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 9d d8 00 00 00 48 89 d9 48 c1 e9 03 48 89 4c 24 08 <80> 3c 01 00 74 08 48 89 df e8 f2 f4 e8 ff 48 89 1c 24 48 8b 1b 48
RSP: 0018:ffffc9000aa87a10 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 00000000000000d6 RCX: 000000000000001a
RDX: 0000000000000000 RSI: 0000000000000004 RDI: fffffffffffffffe
RBP: fffffffffffffffe R08: dffffc0000000000 R09: ffffed100dab82ef
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88806e6e0000
R13: fffffffffffffffc R14: 00000000fffffffe R15: dffffc0000000000
FS: 00007fbc4e794700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005578470fb7a0 CR3: 0000000071785000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 2a 91 ff 48 85 ed sub -0x127ab701(%rcx),%dl
6: 0f 84 56 03 00 00 je 0x362
c: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
13: fc ff df
16: 48 8d 9d d8 00 00 00 lea 0xd8(%rbp),%rbx
1d: 48 89 d9 mov %rbx,%rcx
20: 48 c1 e9 03 shr $0x3,%rcx
24: 48 89 4c 24 08 mov %rcx,0x8(%rsp)
* 29: 80 3c 01 00 cmpb $0x0,(%rcx,%rax,1) <-- trapping instruction
2d: 74 08 je 0x37
2f: 48 89 df mov %rbx,%rdi
32: e8 f2 f4 e8 ff callq 0xffe8f529
37: 48 89 1c 24 mov %rbx,(%rsp)
3b: 48 8b 1b mov (%rbx),%rbx
3e: 48 rex.W

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