Executable loading issues with erofs on arm?

[Gao Xiang]

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));
  }

Thanks,
Gao Xiang