Re: [PATCH 1/1] arch/parisc: mm: fix uninitialized variable usage

[Johannes Weiner <hannes@cmpxchg.org>]

Hello Felipe,

On Sun, Sep 22, 2013 at 03:17:46PM -0300, Felipe Pena wrote:
> The FAULT_FLAG_WRITE flag has been set based on uninitialized variable

Oops, you are right.

> Signed-off-by: Felipe Pena <felipensp@gmail.com>
> ---
>  arch/parisc/mm/fault.c |    5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
> index d10d27a..6b38026 100644
> --- a/arch/parisc/mm/fault.c
> +++ b/arch/parisc/mm/fault.c
> @@ -182,8 +182,6 @@ void do_page_fault(struct pt_regs *regs, unsigned long code,
>  
>  	if (user_mode(regs))
>  		flags |= FAULT_FLAG_USER;
> -	if (acc_type & VM_WRITE)
> -		flags |= FAULT_FLAG_WRITE;
>  retry:
>  	down_read(&mm->mmap_sem);
>  	vma = find_vma_prev(mm, address, &prev_vma);
> @@ -201,6 +199,9 @@ good_area:
>  	if ((vma->vm_flags & acc_type) != acc_type)
>  		goto bad_area;
>  
> +	if (acc_type & VM_WRITE)
> +		flags |= FAULT_FLAG_WRITE;

Can acc_type actually change between between the first round and a
retry?  Otherwise, it might make sense to pull this up and place it
next to the flag initialization instead of pulling one flag down.