Re: [PATCH 1/X] uprobes: write_opcode: the new page needsPG_uptodate

[Srikar Dronamraju]

* Oleg Nesterov <oleg@xxxxxxxxxx> [2011-10-15 21:00:37]:

> write_opcode()->__replace_page() installs the new anonymous page,
> this new_page is PageSwapBacked() and it can be swapped out.
> 
> However it forgets to do SetPageUptodate(), fix write_opcode().
> 
> For example, this is needed if do_swap_page() finds that orginial
> page in the the swap cache (and doesn't try to read it back), in
> this case it returns VM_FAULT_SIGBUS.
> ---
>  kernel/uprobes.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/kernel/uprobes.c b/kernel/uprobes.c
> index 3928bcc..52b20c8 100644
> --- a/kernel/uprobes.c
> +++ b/kernel/uprobes.c
> @@ -200,6 +200,8 @@ static int write_opcode(struct task_struct *tsk, struct uprobe * uprobe,
>  		goto put_out;
>  	}
> 
> +	__SetPageUptodate(new_page);
> +

Agree. 

>  	/*
>  	 * lock page will serialize against do_wp_page()'s
>  	 * PageAnon() handling

-- 
Thanks and Regards
Srikar

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