On 2022-07-26 6:24 p.m., Keith Seitz wrote:

> I've taken your patch and updated mine (now trivial):
> 
> diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
> index 0a93ab5..95732a6 100644
> --- a/gdb/linux-nat.c
> +++ b/gdb/linux-nat.c
> @@ -3710,8 +3712,10 @@ enum target_xfer_status
>        if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
>         offset &= ((ULONGEST) 1 << addr_bit) - 1;
>  
> -      return linux_proc_xfer_memory_partial (readbuf, writebuf,
> -                                            offset, len, xfered_len);
> +      if (proc_mem_file_is_writable ())
> +       return linux_proc_xfer_memory_partial (readbuf, writebuf,
> +                                              offset, len, xfered_len);
> +      /* Fallthrough to ptrace  */
>      }
>  
>    return inf_ptrace_target::xfer_partial (object, annex, readbuf, writebuf,
> 
> I've re-run this through all my testing, and all looks good.

Great, thanks.

> 
> However, I suspect you already knew that. :-)

I was actually curious whether that would work (or rather fail quietly) on the
older kernels!

> 
> If/when you push your patch, and there are no further concerns, I will push mine,
> with your approval.
> 

As discussed off list, I merged both patches to master at once, to avoid "unused"
warnings.

I've attached both patches, as merged.  In my patch, I fixed a bad usage
of gdb::optional (need to emplace once before doing "*opt" ...), and removed
the "static" from the written-to variable (I don't know why I added it in the
first place).  In your patch, I added a comment explaining why not to fallback
to ptrace, in case someone changes this code in the future.

> Thank you for your follow-up!

np.

Pedro Alves.