potential riscv special bug maybe found

[Aurelien Jarno]

Hi,

On 2023-03-09 23:18, Bo YU wrote:
> Hi,
> 
> I am sorry if this is noise.
> 
> Some days ago I noticed strace 6.2 was built failed on riscv64 due to
> test cases[0]. There is one program from strace can reproduce it:
> 
> ```
> ./tests/read-write ```
> 
> It will be hang.
> 
> In fact, the issue has existed since 5.18. I `git bisect` and finally
> found out the issue was introduced by the commit[1]:
> 
> commit 631f871f071746789e9242e514ab0f49067fa97a
> Author: Andreas Gruenbacher <agruenba at redhat.com>
> Date:   Tue Nov 9 12:56:06 2021 +0100
> 
>     fs/iomap: Fix buffered write page prefaulting
> 
> I do not think there is a problem with this commit, because it does not
> affect others arch expect riscv and after I reverted it, it will pass
> all test cases from strace(There is still one case failed on qemu, but
> this is another store).
> 
> I try to debug something but failed.
> Would be appreciated it any help.

Please find attached a simpler reproducer extracted from strace, which
should make the issue easier to reproduce. It hangs on riscv64 and needs
to be killed with -9, while it works fine on amd64.

Regards
Aurelien

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien at aurel32.net                     http://aurel32.net
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