Re: [PATCH AUTOSEL 6.9 02/15] md: Fix overflow in is_mddev_idle

Sasha Levin
2024-06-19T14:27:53Z

On Mon, May 27, 2024 at 09:08:27AM +0800, Yu Kuai wrote:
>Hi,
>
>在 2024/05/26 17:41, Sasha Levin 写道:
>>From: Li Nan <linan122@huawei.com>
>>
>>[ Upstream commit 3f9f231236ce7e48780d8a4f1f8cb9fae2df1e4e ]
>>
>>UBSAN reports this problem:
>>
>> UBSAN: Undefined behaviour in drivers/md/md.c:8175:15
>> signed integer overflow:
>> -2147483291 - 2072033152 cannot be represented in type 'int'
>> Call trace:
>> dump_backtrace+0x0/0x310
>> show_stack+0x28/0x38
>> dump_stack+0xec/0x15c
>> ubsan_epilogue+0x18/0x84
>> handle_overflow+0x14c/0x19c
>> __ubsan_handle_sub_overflow+0x34/0x44
>> is_mddev_idle+0x338/0x3d8
>> md_do_sync+0x1bb8/0x1cf8
>> md_thread+0x220/0x288
>> kthread+0x1d8/0x1e0
>> ret_from_fork+0x10/0x18
>>
>>'curr_events' will overflow when stat accum or 'sync_io' is greater than
>>INT_MAX.
>>
>>Fix it by changing sync_io, last_events and curr_events to 64bit.
>>
>>Signed-off-by: Li Nan <linan122@huawei.com>
>>Reviewed-by: Yu Kuai <yukuai3@huawei.com>
>>Link: https://lore.kernel.org/r/20240117031946.2324519-2-linan666@huaweicloud.com
>>Signed-off-by: Song Liu <song@kernel.org>
>>Signed-off-by: Sasha Levin <sashal@kernel.org>
>
>Hi, please notice that this patch doesn't fix real issue expect for
>the ubsan warning, and this patch is reverted:

I'll drop it, thanks!

--
Thanks,
Sasha