Hello, syzbot found the following issue on:
HEAD commit: b27cc623e01b Add linux-next specific files for 20250610 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=169ac60c580000 kernel config: https://syzkaller.appspot.com/x/.config?x=846e731334efc0f8 dashboard link: https://syzkaller.appspot.com/bug?extid=7c8101d4d0ba2eb511d7 compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/1c0c417339c8/disk-b27cc623.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/fa29c0f3a1fa/vmlinux-b27cc623.xz kernel image: https://storage.googleapis.com/syzbot-assets/b902a80b6e7e/bzImage-b27cc623.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: [email protected] loop2: detected capacity change from 0 to 32768 Oops: divide error: 0000 [#1] SMP KASAN PTI CPU: 0 UID: 0 PID: 6339 Comm: syz.2.181 Not tainted 6.16.0-rc1-next-20250610-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:bch2_sb_members_v2_to_text+0x10a/0x3c0 fs/bcachefs/sb-members.c:347 Code: 49 89 f4 49 c1 ec 03 43 0f b6 0c 34 84 c9 48 89 b4 24 a0 00 00 00 0f 85 67 02 00 00 0f b7 0e 48 89 c2 48 c1 ea 20 74 07 48 99 <48> f7 f9 eb 04 31 d2 f7 f1 48 89 84 24 b0 00 00 00 48 8b 84 24 c8 RSP: 0000:ffffc90003e5ed40 EFLAGS: 00010a02 RAX: ffff888029b58368 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffffffffffffffff RSI: ffff888029b58338 RDI: 0000000000001de6 RBP: ffffc90003e5ef70 R08: 000000000000003a R09: 000000000000003a R10: dffffc0000000000 R11: ffffffff844fcfb0 R12: 1ffff1100536b067 R13: 000000000000000b R14: dffffc0000000000 R15: 1ffff920007cbdc4 FS: 00007f61376166c0(0000) GS:ffff888125c4b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5581bb5f78 CR3: 000000007e792000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> bch2_sb_field_validate+0x1c6/0x280 fs/bcachefs/super-io.c:1380 bch2_sb_validate+0x14bd/0x1980 fs/bcachefs/super-io.c:552 __bch2_read_super+0xba4/0x1040 fs/bcachefs/super-io.c:925 bch2_fs_open+0x1fe/0x2570 fs/bcachefs/super.c:2382 bch2_fs_get_tree+0x437/0x14f0 fs/bcachefs/fs.c:2473 vfs_get_tree+0x8f/0x2b0 fs/super.c:1802 do_new_mount+0x24a/0xa40 fs/namespace.c:3885 do_mount fs/namespace.c:4222 [inline] __do_sys_mount fs/namespace.c:4433 [inline] __se_sys_mount+0x317/0x410 fs/namespace.c:4410 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f61367900ca Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f6137615e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f6137615ef0 RCX: 00007f61367900ca RDX: 0000200000000000 RSI: 0000200000011a40 RDI: 00007f6137615eb0 RBP: 0000200000000000 R08: 00007f6137615ef0 R09: 00000000028080c9 R10: 00000000028080c9 R11: 0000000000000246 R12: 0000200000011a40 R13: 00007f6137615eb0 R14: 00000000000119f9 R15: 0000200000013d00 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:bch2_sb_members_v2_to_text+0x10a/0x3c0 fs/bcachefs/sb-members.c:347 Code: 49 89 f4 49 c1 ec 03 43 0f b6 0c 34 84 c9 48 89 b4 24 a0 00 00 00 0f 85 67 02 00 00 0f b7 0e 48 89 c2 48 c1 ea 20 74 07 48 99 <48> f7 f9 eb 04 31 d2 f7 f1 48 89 84 24 b0 00 00 00 48 8b 84 24 c8 RSP: 0000:ffffc90003e5ed40 EFLAGS: 00010a02 RAX: ffff888029b58368 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffffffffffffffff RSI: ffff888029b58338 RDI: 0000000000001de6 RBP: ffffc90003e5ef70 R08: 000000000000003a R09: 000000000000003a R10: dffffc0000000000 R11: ffffffff844fcfb0 R12: 1ffff1100536b067 R13: 000000000000000b R14: dffffc0000000000 R15: 1ffff920007cbdc4 FS: 00007f61376166c0(0000) GS:ffff888125c4b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f961d79c000 CR3: 000000007e792000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 49 89 f4 mov %rsi,%r12 3: 49 c1 ec 03 shr $0x3,%r12 7: 43 0f b6 0c 34 movzbl (%r12,%r14,1),%ecx c: 84 c9 test %cl,%cl e: 48 89 b4 24 a0 00 00 mov %rsi,0xa0(%rsp) 15: 00 16: 0f 85 67 02 00 00 jne 0x283 1c: 0f b7 0e movzwl (%rsi),%ecx 1f: 48 89 c2 mov %rax,%rdx 22: 48 c1 ea 20 shr $0x20,%rdx 26: 74 07 je 0x2f 28: 48 99 cqto * 2a: 48 f7 f9 idiv %rcx <-- trapping instruction 2d: eb 04 jmp 0x33 2f: 31 d2 xor %edx,%edx 31: f7 f1 div %ecx 33: 48 89 84 24 b0 00 00 mov %rax,0xb0(%rsp) 3a: 00 3b: 48 rex.W 3c: 8b .byte 0x8b 3d: 84 24 c8 test %ah,(%rax,%rcx,8) --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at [email protected]. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
