Re: Executable loading issues with erofs on arm?

[Jan Kiszka <jan.kiszka@siemens.com>]

On 08.07.25 17:57, Gao Xiang wrote:
> 
> 
> On 2025/7/8 23:36, Gao Xiang wrote:
>>
>>
>> On 2025/7/8 23:32, Gao Xiang wrote:
>>>
>>>
>>> On 2025/7/8 23:22, Jan Kiszka wrote:
>>>> On 08.07.25 17:12, Gao Xiang wrote:
>>>>> Hi Jan,
>>>>>
>>>>> On 2025/7/8 20:43, Jan Kiszka wrote:
>>>>>> On 08.07.25 14:41, Jan Kiszka wrote:
>>>>>>> Hi all,
>>>>>>>
>>>>>>> for some days, I'm trying to understand if we have an integration
>>>>>>> issue
>>>>>>> with erofs or rather some upstream bug. After playing with various
>>>>>>> parameters, it rather looks like the latter:
>>>>>>>
>>>>>>> $ ls -l erofs-dir/
>>>>>>> total 132
>>>>>>> -rwxr-xr-x 1 1000 users 132868 Jul  8 10:50 dash
>>>>>>> (from Debian bookworm)
>>>>>>> $ mkfs.erofs -z lz4hc erofs.img erofs-dir/
>>>>>>> mkfs.erofs 1.8.6 (trixie version, but same happens with bookworm
>>>>>>> 1.5)
>>>>>>> Build completed.
>>>>>>> ------
>>>>>>> Filesystem UUID: aae0b2f0-4ee4-4850-af49-3c1aad7fa30c
>>>>>>> Filesystem total blocks: 17 (of 4096-byte blocks)
>>>>>>> Filesystem total inodes: 2
>>>>>>> Filesystem total metadata blocks: 1
>>>>>>> Filesystem total deduplicated bytes (of source files): 0
>>>>>>>
>>>>>>> Now I have 6.15-rc5 and a defconfig-close setting for the 32-bit ARM
>>>>>>> target BeagleBone Black. When booting into init=/bin/sh, then
>>>>>>> running
>>>>>>>
>>>>>>> # mount -t erofs /dev/mmcblk0p1 /mnt
>>>>>>> erofs (device mmcblk0p1): mounted with root inode @ nid 36.
>>>>>>> # /mnt/dash
>>>>>>> Segmentation fault
>>
>> Two extra quick questions:
>>   - If the segfault happens, then if you run /mnt/dash again, does
>>     segfault still happen?
>>
>>   - If the /mnt/dash segfault happens, then if you run
>>       cat /mnt/dash > /dev/null
>>       /mnt/dash
>>     does segfault still happen?
> 
> Oh, sorry I didn't read the full hints, could you check if
> the following patch resolve the issue (space-damaged)?
> 
> diff --git a/fs/erofs/data.c b/fs/erofs/data.c
> index 6a329c329f43..701490b3ef7d 100644
> --- a/fs/erofs/data.c
> +++ b/fs/erofs/data.c
> @@ -245,6 +245,7 @@ void erofs_onlinefolio_end(struct folio *folio, int
> err)
>         if (v & ~EROFS_ONLINEFOLIO_EIO)
>                 return;
>         folio->private = 0;
> +       flush_dcache_folio(folio);
>         folio_end_read(folio, !(v & EROFS_ONLINEFOLIO_EIO));
>  }
> 

Yeah, indeed that seem to have helped with the minimal test. Will do the
full scenario test (complete rootfs) next.

Jan

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