syzbot

loop3: detected capacity change from 0 to 32768
Oops: divide error: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 1 UID: 0 PID: 5591 Comm: syz.3.64 Not tainted 6.11.0-syzkaller-07462-g1868f9d0260e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
RIP: 0010:div_u64_rem include/linux/math64.h:29 [inline]
RIP: 0010:div_u64 include/linux/math64.h:130 [inline]
RIP: 0010:__bch2_strtou64_h fs/bcachefs/util.c:143 [inline]
RIP: 0010:__bch2_strtoh+0xb59/0xeb0 fs/bcachefs/util.c:168
Code: ff 0f 88 8f 00 00 00 4c 89 74 24 08 44 89 f8 48 01 c5 48 89 2c 24 e8 56 40 49 fd 4d 89 e6 44 89 e1 48 c7 c0 ff ff ff ff 31 d2 <48> f7 f1 48 89 c5 48 8b 5c 24 18 48 89 df 48 89 c6 e8 91 42 49 fd
RSP: 0018:ffffc900096278e8 EFLAGS: 00010246
RAX: ffffffffffffffff RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 000000000000079e RDI: 000000000000079f
RBP: ffff888027f2ffc2 R08: ffffffff844b7ead R09: 0000000000000000
R10: 0000000000000009 R11: ffff888024b09e00 R12: 1000000000000000
R13: ffff888027f2ffc0 R14: 1000000000000000 R15: 0000000000000001
FS:  00007efc3fb456c0(0000) GS:ffff8880b8900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efc3ed60700 CR3: 000000002681a000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 bch2_strtou64_h+0xa5/0x120 fs/bcachefs/util.c:205
 bch2_opt_parse+0x2dd/0x4c0 fs/bcachefs/opts.c:353
 bch2_parse_one_mount_opt+0x2d3/0x5e0 fs/bcachefs/opts.c:501
 bch2_fs_parse_param+0x137/0x180 fs/bcachefs/fs.c:2095
 vfs_parse_fs_param+0x1a7/0x420 fs/fs_context.c:146
 vfs_parse_fs_string fs/fs_context.c:188 [inline]
 vfs_parse_monolithic_sep fs/fs_context.c:230 [inline]
 generic_parse_monolithic+0x2c8/0x400 fs/fs_context.c:258
 do_new_mount+0x28f/0xb40 fs/namespace.c:3503
 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: 0033:0x7efc3ed7f69a
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:00007efc3fb44e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007efc3fb44ef0 RCX: 00007efc3ed7f69a
RDX: 0000000020000040 RSI: 000000002000f680 RDI: 00007efc3fb44eb0
RBP: 0000000020000040 R08: 00007efc3fb44ef0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000002000f680
R13: 00007efc3fb44eb0 R14: 000000000000f633 R15: 00000000200000c0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:div_u64_rem include/linux/math64.h:29 [inline]
RIP: 0010:div_u64 include/linux/math64.h:130 [inline]
RIP: 0010:__bch2_strtou64_h fs/bcachefs/util.c:143 [inline]
RIP: 0010:__bch2_strtoh+0xb59/0xeb0 fs/bcachefs/util.c:168
Code: ff 0f 88 8f 00 00 00 4c 89 74 24 08 44 89 f8 48 01 c5 48 89 2c 24 e8 56 40 49 fd 4d 89 e6 44 89 e1 48 c7 c0 ff ff ff ff 31 d2 <48> f7 f1 48 89 c5 48 8b 5c 24 18 48 89 df 48 89 c6 e8 91 42 49 fd
RSP: 0018:ffffc900096278e8 EFLAGS: 00010246
RAX: ffffffffffffffff RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 000000000000079e RDI: 000000000000079f
RBP: ffff888027f2ffc2 R08: ffffffff844b7ead R09: 0000000000000000
R10: 0000000000000009 R11: ffff888024b09e00 R12: 1000000000000000
R13: ffff888027f2ffc0 R14: 1000000000000000 R15: 0000000000000001
FS:  00007efc3fb456c0(0000) GS:ffff8880b8800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020003142 CR3: 000000002681a000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess):
   0:	ff 0f                	decl   (%rdi)
   2:	88 8f 00 00 00 4c    	mov    %cl,0x4c000000(%rdi)
   8:	89 74 24 08          	mov    %esi,0x8(%rsp)
   c:	44 89 f8             	mov    %r15d,%eax
   f:	48 01 c5             	add    %rax,%rbp
  12:	48 89 2c 24          	mov    %rbp,(%rsp)
  16:	e8 56 40 49 fd       	call   0xfd494071
  1b:	4d 89 e6             	mov    %r12,%r14
  1e:	44 89 e1             	mov    %r12d,%ecx
  21:	48 c7 c0 ff ff ff ff 	mov    $0xffffffffffffffff,%rax
  28:	31 d2                	xor    %edx,%edx
* 2a:	48 f7 f1             	div    %rcx <-- trapping instruction
  2d:	48 89 c5             	mov    %rax,%rbp
  30:	48 8b 5c 24 18       	mov    0x18(%rsp),%rbx
  35:	48 89 df             	mov    %rbx,%rdi
  38:	48 89 c6             	mov    %rax,%rsi
  3b:	e8 91 42 49 fd       	call   0xfd4942d1