[syzbot] [bcachefs?] general protection fault in gen_poly_key

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    4a4be1ad3a6e Revert "vfs: Delete the associated dentry whe..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11ae4d14980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=238430243a58f702
dashboard link: https://syzkaller.appspot.com/bug?extid=0c7a9c4a5a4b3730d4f6
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=101c3162980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1432099a980000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-4a4be1ad.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e90895495e65/vmlinux-4a4be1ad.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9e28d1589c72/bzImage-4a4be1ad.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/83e4344d1bf8/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0c7a9c4a5a4b3730d4f6@xxxxxxxxxxxxxxxxxxxxxxxxx

Oops: general protection fault, probably for non-canonical address 0xdffffc000000903d: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: probably user-memory-access in range [0x00000000000481e8-0x00000000000481ef]
CPU: 1 PID: 5189 Comm: syz-executor842 Not tainted 6.10.0-rc1-syzkaller-00027-g4a4be1ad3a6e #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:gen_poly_key.isra.0+0x10d/0x330 fs/bcachefs/checksum.c:191
Code: 00 00 00 00 05 00 00 00 80 89 44 24 0c e8 db 56 f0 fd 49 8d bd e8 81 04 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 ce 01 00 00 4c 89 fa 4d 8b 8d e8 81 04 00 48 b8
RSP: 0018:ffffc900031eee48 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 1ffff9200063ddcb RCX: 0000000000000000
RDX: 000000000000903d RSI: 0000000000000000 RDI: 00000000000481e8
RBP: ffffc900031eef20 R08: 0000000000000001 R09: 0000000000000000
R10: ffffc900031eee98 R11: 0000000000000000 R12: ffffc900031eee98
R13: 0000000000000000 R14: ffffc900031ef028 R15: ffffc900031eee84
FS:  0000555568ecb380(0000) GS:ffff88806b100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055954aed89d8 CR3: 00000000236b0000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 bch2_checksum+0x1f9/0x2e0 fs/bcachefs/checksum.c:227
 read_one_super+0x567/0x1530 fs/bcachefs/super-io.c:672
 __bch2_read_super+0xc81/0x12a0 fs/bcachefs/super-io.c:797
 bch2_fs_open+0x3e5/0x1110 fs/bcachefs/super.c:2070
 bch2_mount+0xdcc/0x1130 fs/bcachefs/fs.c:1917
 legacy_get_tree+0x109/0x220 fs/fs_context.c:662
 vfs_get_tree+0x8f/0x380 fs/super.c:1780
 do_new_mount fs/namespace.c:3352 [inline]
 path_mount+0x14e6/0x1f20 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount fs/namespace.c:3875 [inline]
 __x64_sys_mount+0x297/0x320 fs/namespace.c:3875
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc8c1cf78fa
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:00007ffdfeaaa7e8 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffdfeaaa800 RCX: 00007fc8c1cf78fa
RDX: 0000000020005d80 RSI: 0000000020005dc0 RDI: 00007ffdfeaaa800
RBP: 0000000000000004 R08: 00007ffdfeaaa840 R09: 0000000000005d9b
R10: 0000000000000480 R11: 0000000000000282 R12: 0000000000000480
R13: 00007ffdfeaaa840 R14: 0000000000000003 R15: 0000000001000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:gen_poly_key.isra.0+0x10d/0x330 fs/bcachefs/checksum.c:191
Code: 00 00 00 00 05 00 00 00 80 89 44 24 0c e8 db 56 f0 fd 49 8d bd e8 81 04 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 ce 01 00 00 4c 89 fa 4d 8b 8d e8 81 04 00 48 b8
RSP: 0018:ffffc900031eee48 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 1ffff9200063ddcb RCX: 0000000000000000
RDX: 000000000000903d RSI: 0000000000000000 RDI: 00000000000481e8
RBP: ffffc900031eef20 R08: 0000000000000001 R09: 0000000000000000
R10: ffffc900031eee98 R11: 0000000000000000 R12: ffffc900031eee98
R13: 0000000000000000 R14: ffffc900031ef028 R15: ffffc900031eee84
FS:  0000555568ecb380(0000) GS:ffff88806b100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055954aed89d8 CR3: 00000000236b0000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	00 00                	add    %al,(%rax)
   4:	05 00 00 00 80       	add    $0x80000000,%eax
   9:	89 44 24 0c          	mov    %eax,0xc(%rsp)
   d:	e8 db 56 f0 fd       	call   0xfdf056ed
  12:	49 8d bd e8 81 04 00 	lea    0x481e8(%r13),%rdi
  19:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  20:	fc ff df
  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 ce 01 00 00    	jne    0x202
  34:	4c 89 fa             	mov    %r15,%rdx
  37:	4d 8b 8d e8 81 04 00 	mov    0x481e8(%r13),%r9
  3e:	48                   	rex.W
  3f:	b8                   	.byte 0xb8


---
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