linux-kernel - Re: [PATCH v4 tip/perf/core 3/4] uprobes: simplify find_active_uprobe

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Message-Id: <20241028105123.c97544285c7e3304138c5a40@kernel.org>
Date: Mon, 28 Oct 2024 10:51:23 +0900
From: Masami Hiramatsu (Google) <mhiramat@...nel.org>
To: Andrii Nakryiko <andrii@...nel.org>
Cc: linux-trace-kernel@...r.kernel.org, linux-mm@...ck.org,
 akpm@...ux-foundation.org, peterz@...radead.org, oleg@...hat.com,
 rostedt@...dmis.org, mhiramat@...nel.org, bpf@...r.kernel.org,
 linux-kernel@...r.kernel.org, jolsa@...nel.org, paulmck@...nel.org,
 willy@...radead.org, surenb@...gle.com, mjguzik@...il.com,
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 shakeel.butt@...ux.dev, hannes@...xchg.org, Liam.Howlett@...cle.com,
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 richard.weiyang@...il.com, zhangpeng.00@...edance.com,
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Subject: Re: [PATCH v4 tip/perf/core 3/4] uprobes: simplify
 find_active_uprobe_rcu() VMA checks

On Sun, 27 Oct 2024 18:08:17 -0700
Andrii Nakryiko <andrii@...nel.org> 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@...nel.org>

Thanks,

> Acked-by: Oleg Nesterov <oleg@...hat.com>
> Suggested-by: Oleg Nesterov <oleg@...hat.com>
> Signed-off-by: Andrii Nakryiko <andrii@...nel.org>
> ---
>  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@...nel.org>