Message-ID: <000000000000914c1206002dc099@google.com>
Date:   Mon, 10 Jul 2023 20:32:44 -0700
From:   syzbot <syzbot+b592c1f562f0da80ce2c@...kaller.appspotmail.com>
To:     amir73il@...il.com, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-unionfs@...r.kernel.org,
        miklos@...redi.hu, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [overlayfs?] general protection fault in ovl_init_uuid_xattr

Hello,

syzbot found the following issue on:

HEAD commit:    123212f53f3e Add linux-next specific files for 20230707
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=12353b44a80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=15ec80b62f588543
dashboard link: https://syzkaller.appspot.com/bug?extid=b592c1f562f0da80ce2c
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15741e22a80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1105b4e2a80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/098f7ee2237c/disk-123212f5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/88defebbfc49/vmlinux-123212f5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d5e9343ec16a/bzImage-123212f5.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b592c1f562f0da80ce2c@...kaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc000000001c: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000000e0-0x00000000000000e7]
CPU: 1 PID: 5024 Comm: syz-executor280 Not tainted 6.4.0-next-20230707-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
RIP: 0010:ovl_do_getxattr fs/overlayfs/overlayfs.h:263 [inline]
RIP: 0010:ovl_path_getxattr fs/overlayfs/overlayfs.h:292 [inline]
RIP: 0010:ovl_init_uuid_xattr+0x1f6/0xa90 fs/overlayfs/util.c:695
Code: c1 ea 03 80 3c 02 00 0f 85 54 08 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 74 24 08 48 8d be e0 00 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 f2 07 00 00 4c 89 e1 48 8b 86 e0 00 00 00 48 ba
RSP: 0018:ffffc90003aafab8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff888014e67c00 RCX: 0000000000000005
RDX: 000000000000001c RSI: 0000000000000000 RDI: 00000000000000e0
RBP: ffff888029c04678 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88801927c480
R13: ffff888014e67c79 R14: ffff888014e67c60 R15: 0000000000000000
FS:  0000555556b13300(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001000 CR3: 0000000022580000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ovl_fill_super+0x1f94/0x5d70 fs/overlayfs/super.c:1437
 vfs_get_super+0xea/0x280 fs/super.c:1152
 vfs_get_tree+0x8d/0x350 fs/super.c:1519
 do_new_mount fs/namespace.c:3335 [inline]
 path_mount+0x136e/0x1e70 fs/namespace.c:3662
 do_mount fs/namespace.c:3675 [inline]
 __do_sys_mount fs/namespace.c:3884 [inline]
 __se_sys_mount fs/namespace.c:3861 [inline]
 __x64_sys_mount+0x283/0x300 fs/namespace.c:3861
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f60c9bc0b09
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc22c0ccf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 00007f60c9bc0b09
RDX: 00000000200000c0 RSI: 0000000020000200 RDI: 0000000000000000
RBP: 00007f60c9b84cb0 R08: 0000000020000480 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f60c9b84d40
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ovl_do_getxattr fs/overlayfs/overlayfs.h:263 [inline]
RIP: 0010:ovl_path_getxattr fs/overlayfs/overlayfs.h:292 [inline]
RIP: 0010:ovl_init_uuid_xattr+0x1f6/0xa90 fs/overlayfs/util.c:695
Code: c1 ea 03 80 3c 02 00 0f 85 54 08 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 74 24 08 48 8d be e0 00 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 f2 07 00 00 4c 89 e1 48 8b 86 e0 00 00 00 48 ba
RSP: 0018:ffffc90003aafab8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff888014e67c00 RCX: 0000000000000005
RDX: 000000000000001c RSI: 0000000000000000 RDI: 00000000000000e0
RBP: ffff888029c04678 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88801927c480
R13: ffff888014e67c79 R14: ffff888014e67c60 R15: 0000000000000000
FS:  0000555556b13300(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001000 CR3: 0000000022580000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	c1 ea 03             	shr    $0x3,%edx
   3:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   7:	0f 85 54 08 00 00    	jne    0x861
   d:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  14:	fc ff df
  17:	49 8b 74 24 08       	mov    0x8(%r12),%rsi
  1c:	48 8d be e0 00 00 00 	lea    0xe0(%rsi),%rdi
  23:	48 89 fa             	mov    %rdi,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2e:	0f 85 f2 07 00 00    	jne    0x826
  34:	4c 89 e1             	mov    %r12,%rcx
  37:	48 8b 86 e0 00 00 00 	mov    0xe0(%rsi),%rax
  3e:	48                   	rex.W
  3f:	ba                   	.byte 0xba


---
This report is generated by a bot. It may contain errors.
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