Re: [Patch 1/2] ia32: use generic sys_pipe()

[Amerigo Wang]

Ingo Molnar wrote:
> * Amerigo Wang <amwang@xxxxxxxxxx> wrote:
>
>   
> > As suggested by Al, it's better to use the generic sys_pipe() for 
> > ia32.
> >
> > Signed-off-by: WANG Cong <amwang@xxxxxxxxxx>
> > Cc: Ingo Molnar <mingo@xxxxxxx>
> > Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> > CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> >     
>
>   
> > --- a/arch/x86/ia32/sys_ia32.c
> > +++ b/arch/x86/ia32/sys_ia32.c
> > @@ -189,20 +189,6 @@ asmlinkage long sys32_mprotect(unsigned long start, size_t len,
> >  	return sys_mprotect(start, len, prot);
> >  }
> >  
> > -asmlinkage long sys32_pipe(int __user *fd)
> > -{
> > -	int retval;
> > -	int fds[2];
> > -
> > -	retval = do_pipe_flags(fds, 0);
> > -	if (retval)
> > -		goto out;
> > -	if (copy_to_user(fd, fds, sizeof(fds)))
> > -		retval = -EFAULT;
> > -out:
> > -	return retval;
> > -}
> >     
>
> Please _ALWAYS_ mention the change in behavior in the changelog, 
> just in case someone ends up bisecting it. I only found out when i 
> reviewed the two syscalls out of caution.
>
> The syscall you remove kept stale fd's around in case of -EFAULT 
> from copy_to_user(). The generic version does an explicit close of 
> those files:
>
>                         sys_close(fd[0]);
>                         sys_close(fd[1]);
>                         error = -EFAULT;
>
> The generic version looks like the better choice to me but this 
> difference should be mentioned in the changelog nevertheless, just 
> in case some buggy app runs into this issue.
>   

Hi, yes, exactly.
Thank you! I will be careful next time.

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