Re: [PATCH v4 tip/perf/core 3/4] uprobes: simplify find_active_uprobe_rcu() VMA checks

[Google]

On Sun, 27 Oct 2024 18:08:17 -0700
Andrii Nakryiko <andrii@xxxxxxxxxx> wrote:

> At the point where find_active_uprobe_rcu() is used we know that VMA in
> question has triggered software breakpoint, so we don't need to validate
> vma->vm_flags. Keep only vma->vm_file NULL check.
> 

Looks good to me.

Reviewed-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>

Thanks,

> Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> Suggested-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> ---
>  kernel/events/uprobes.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> index 4ef4b51776eb..290c445768fa 100644
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -2084,7 +2084,7 @@ static struct uprobe *find_active_uprobe_rcu(unsigned long bp_vaddr, int *is_swb
>  	mmap_read_lock(mm);
>  	vma = vma_lookup(mm, bp_vaddr);
>  	if (vma) {
> -		if (valid_vma(vma, false)) {
> +		if (vma->vm_file) {
>  			struct inode *inode = file_inode(vma->vm_file);
>  			loff_t offset = vaddr_to_offset(vma, bp_vaddr);
>  
> -- 
> 2.43.5
> 


-- 
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>