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UBSAN: division-overflow in ./include/linux/math64.h:69:18
division by zero
CPU: 1 UID: 0 PID: 5621 Comm: sh Not tainted 6.12.0-rc4 #1
Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x180/0x1b0 lib/dump_stack.c:120
 ubsan_epilogue lib/ubsan.c:231 [inline]
 __ubsan_handle_divrem_overflow+0x13d/0x1d0 lib/ubsan.c:325
 div64_u64 include/linux/math64.h:69 [inline]
 bdi_ratio_from_pages mm/page-writeback.c:695 [inline]
 bdi_set_min_bytes.cold+0x16/0x1b mm/page-writeback.c:799
 min_bytes_store+0xbc/0x130 mm/backing-dev.c:385
 dev_attr_store+0x57/0x80 drivers/base/core.c:2447
 sysfs_kf_write+0x117/0x170 fs/sysfs/file.c:136
 kernfs_fop_write_iter+0x33c/0x500 fs/kernfs/file.c:334
 new_sync_write fs/read_write.c:590 [inline]
 vfs_write+0xbcb/0x10d0 fs/read_write.c:683
 ksys_write+0x122/0x250 fs/read_write.c:736
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xbf/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1cb2a144b3
Code: 8b 15 e1 29 0e 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 64 8b 04 25 18 00 00 00 85 c0 75 14 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 55 c3 0f 1f 40 00 48 83 ec 28 48 89 54 24 18
RSP: 002b:00007ffc1fcfe238 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00005627eaeeb6b0 RCX: 00007f1cb2a144b3
RDX: 0000000000000002 RSI: 00005627eaeeb6b0 RDI: 0000000000000001
RBP: 0000000000000002 R08: 00005627eaeeb6b0 R09: 00007f1cb2af7be0
R10: 0000000000000070 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000002 R14: 7fffffffffffffff R15: 0000000000000000
 </TASK>
---[ end trace ]---
Oops: divide error: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 1 UID: 0 PID: 5621 Comm: sh Not tainted 6.12.0-rc4 #1
Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:div64_u64 include/linux/math64.h:69 [inline]
RIP: 0010:bdi_ratio_from_pages mm/page-writeback.c:695 [inline]
RIP: 0010:bdi_set_min_bytes+0xcf/0x240 mm/page-writeback.c:799
Code: f4 ff ff 4c 8b 6c 24 40 31 ff 4c 89 ee e8 b9 4f e4 ff 4d 85 ed 0f 84 9c 1c 02 03 e8 4b 4c e4 ff 48 89 d8 31 d2 bf 40 42 0f 00 <49> f7 f5 48 89 c3 89 c6 e8 64 4f e4 ff 81 fb 40 42 0f 00 0f 87 39
RSP: 0018:ffff8881090dfb58 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8119c0fe
RDX: 0000000000000000 RSI: ffffffff816f00e5 RDI: 00000000000f4240
RBP: ffff888103a6e000 R08: 0000000000000001 R09: fffffbfff0f4f600
R10: 0000000000000000 R11: 0000000000000001 R12: 1ffff1102121bf6b
R13: 0000000000000000 R14: ffff888103a6e000 R15: ffffffff81b7fc00
FS:  00007f1cb2afe580(0000) GS:ffff888117e80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005627eaeed6b8 CR3: 000000010c21a000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 min_bytes_store+0xbc/0x130 mm/backing-dev.c:385
 dev_attr_store+0x57/0x80 drivers/base/core.c:2447
 sysfs_kf_write+0x117/0x170 fs/sysfs/file.c:136
 kernfs_fop_write_iter+0x33c/0x500 fs/kernfs/file.c:334
 new_sync_write fs/read_write.c:590 [inline]
 vfs_write+0xbcb/0x10d0 fs/read_write.c:683
 ksys_write+0x122/0x250 fs/read_write.c:736
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xbf/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1cb2a144b3
Code: 8b 15 e1 29 0e 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 64 8b 04 25 18 00 00 00 85 c0 75 14 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 55 c3 0f 1f 40 00 48 83 ec 28 48 89 54 24 18
RSP: 002b:00007ffc1fcfe238 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00005627eaeeb6b0 RCX: 00007f1cb2a144b3
RDX: 0000000000000002 RSI: 00005627eaeeb6b0 RDI: 0000000000000001
RBP: 0000000000000002 R08: 00005627eaeeb6b0 R09: 00007f1cb2af7be0
R10: 0000000000000070 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000002 R14: 7fffffffffffffff R15: 0000000000000000
 </TASK>
Modules linked in:
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	ff 4c 8b 6c          	decl   0x6c(%rbx,%rcx,4)
   4:	24 40                	and    $0x40,%al
   6:	31 ff                	xor    %edi,%edi
   8:	4c 89 ee             	mov    %r13,%rsi
   b:	e8 b9 4f e4 ff       	call   0xffe44fc9
  10:	4d 85 ed             	test   %r13,%r13
  13:	0f 84 9c 1c 02 03    	je     0x3021cb5
  19:	e8 4b 4c e4 ff       	call   0xffe44c69
  1e:	48 89 d8             	mov    %rbx,%rax
  21:	31 d2                	xor    %edx,%edx
  23:	bf 40 42 0f 00       	mov    $0xf4240,%edi
* 28:	49 f7 f5             	div    %r13 <-- trapping instruction
  2b:	48 89 c3             	mov    %rax,%rbx
  2e:	89 c6                	mov    %eax,%esi
  30:	e8 64 4f e4 ff       	call   0xffe44f99
  35:	81 fb 40 42 0f 00    	cmp    $0xf4240,%ebx
  3b:	0f                   	.byte 0xf
  3c:	87 39                	xchg   %edi,(%rcx)