linux-kernel - [syzbot] [bcachefs?] general protection fault in __copy

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Message-ID: <66eea5a2.050a0220.3195df.004b.GAE@google.com>
Date: Sat, 21 Sep 2024 03:53:22 -0700
From: syzbot <syzbot+18a5c5e8a9c856944876@...kaller.appspotmail.com>
To: kent.overstreet@...ux.dev, linux-bcachefs@...r.kernel.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [bcachefs?] general protection fault in __copy_super

Hello,

syzbot found the following issue on:

HEAD commit:    a430d95c5efa Merge tag 'lsm-pr-20240911' of git://git.kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=124e6a77980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1653f803fffa3848
dashboard link: https://syzkaller.appspot.com/bug?extid=18a5c5e8a9c856944876
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=129f68a9980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1539e29f980000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-a430d95c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/66a65abf87c4/vmlinux-a430d95c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/09c88015f9aa/bzImage-a430d95c.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/97dbec0f4717/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+18a5c5e8a9c856944876@...kaller.appspotmail.com

bcachefs (/dev/loop0): error reading default superblock: checksum error, type crc32c_nonzero: got 151109cf should be 29d2fb78
bcachefs (/dev/loop0): error reading superblock: checksum error, type crc32c_nonzero: got 151109cf should be 29d2fb78
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 0 UID: 0 PID: 5098 Comm: syz-executor282 Not tainted 6.11.0-syzkaller-02574-ga430d95c5efa #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:__copy_super+0x59/0xe70 fs/bcachefs/super-io.c:552
Code: 44 24 10 80 3c 18 00 74 12 4c 89 f7 e8 90 71 b5 fd 48 ba 00 00 00 00 00 fc ff df 4d 8b 3e 49 8d 5c 24 10 48 89 d8 48 c1 e8 03 <0f> b6 04 10 84 c0 0f 85 2e 0c 00 00 0f b7 2b 49 8d 5f 10 48 89 d8
RSP: 0018:ffffc90002f8f2f0 EFLAGS: 00010202
RAX: 0000000000000002 RBX: 0000000000000010 RCX: ffff888000ebc880
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff888044d807d8
RBP: 0000000000000000 R08: ffffffff84457905 R09: 00000000ffffffff
R10: dffffc0000000000 R11: fffffbfff2845f24 R12: 0000000000000000
R13: ffff888044d80000 R14: ffff888044d807d8 R15: ffff88803fb32800
FS:  00005555893e4380(0000) GS:ffff88801fe00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555cf75a4000 CR3: 0000000011efe000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 bch2_sb_to_fs+0xab/0x150 fs/bcachefs/super-io.c:610
 bch2_fs_alloc+0xd5c/0x20b0 fs/bcachefs/super.c:828
 bch2_fs_open+0x8cc/0xdf0 fs/bcachefs/super.c:2115
 bch2_fs_get_tree+0x731/0x1700 fs/bcachefs/fs.c:1943
 vfs_get_tree+0x90/0x2b0 fs/super.c:1800
 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: 0033:0x7f2b30c1706a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 5e 04 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe211af6b8 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffe211af6d0 RCX: 00007f2b30c1706a
RDX: 0000000020000240 RSI: 0000000020005dc0 RDI: 00007ffe211af6d0
RBP: 0000000000000004 R08: 00007ffe211af710 R09: 0000000000005da0
R10: 0000000001000000 R11: 0000000000000282 R12: 0000000001000000
R13: 00007ffe211af710 R14: 0000000000000003 R15: 0000000001000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__copy_super+0x59/0xe70 fs/bcachefs/super-io.c:552
Code: 44 24 10 80 3c 18 00 74 12 4c 89 f7 e8 90 71 b5 fd 48 ba 00 00 00 00 00 fc ff df 4d 8b 3e 49 8d 5c 24 10 48 89 d8 48 c1 e8 03 <0f> b6 04 10 84 c0 0f 85 2e 0c 00 00 0f b7 2b 49 8d 5f 10 48 89 d8
RSP: 0018:ffffc90002f8f2f0 EFLAGS: 00010202
RAX: 0000000000000002 RBX: 0000000000000010 RCX: ffff888000ebc880
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff888044d807d8
RBP: 0000000000000000 R08: ffffffff84457905 R09: 00000000ffffffff
R10: dffffc0000000000 R11: fffffbfff2845f24 R12: 0000000000000000
R13: ffff888044d80000 R14: ffff888044d807d8 R15: ffff88803fb32800
FS:  00005555893e4380(0000) GS:ffff88801fe00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555cf75a4000 CR3: 0000000011efe000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	44 24 10             	rex.R and $0x10,%al
   3:	80 3c 18 00          	cmpb   $0x0,(%rax,%rbx,1)
   7:	74 12                	je     0x1b
   9:	4c 89 f7             	mov    %r14,%rdi
   c:	e8 90 71 b5 fd       	call   0xfdb571a1
  11:	48 ba 00 00 00 00 00 	movabs $0xdffffc0000000000,%rdx
  18:	fc ff df
  1b:	4d 8b 3e             	mov    (%r14),%r15
  1e:	49 8d 5c 24 10       	lea    0x10(%r12),%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	0f b6 04 10          	movzbl (%rax,%rdx,1),%eax <-- trapping instruction
  2e:	84 c0                	test   %al,%al
  30:	0f 85 2e 0c 00 00    	jne    0xc64
  36:	0f b7 2b             	movzwl (%rbx),%ebp
  39:	49 8d 5f 10          	lea    0x10(%r15),%rbx
  3d:	48 89 d8             	mov    %rbx,%rax


---
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