linux-kernel - Re: [PATCH] mm/memory-failure: Poison read receives SIGKILL instead of SIGBUS if mmaped more than once

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Message-ID: <20190724013840.GS363@bombadil.infradead.org>
Date:   Tue, 23 Jul 2019 18:38:40 -0700
From:   Matthew Wilcox <willy@...radead.org>
To:     Jane Chu <jane.chu@...cle.com>
Cc:     n-horiguchi@...jp.nec.com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, linux-nvdimm@...ts.01.org
Subject: Re: [PATCH] mm/memory-failure: Poison read receives SIGKILL instead
 of SIGBUS if mmaped more than once

On Tue, Jul 23, 2019 at 05:38:30PM -0600, Jane Chu wrote:
> @@ -331,16 +330,21 @@ static void add_to_kill(struct task_struct *tsk, struct page *p,
>  		tk->size_shift = compound_order(compound_head(p)) + PAGE_SHIFT;
>  
>  	/*
> -	 * In theory we don't have to kill when the page was
> -	 * munmaped. But it could be also a mremap. Since that's
> -	 * likely very rare kill anyways just out of paranoia, but use
> -	 * a SIGKILL because the error is not contained anymore.
> +	 * Indeed a page could be mmapped N times within a process. And it's possible

You should run this patch through checkpatch.pl so I don't have to tell
you whats wrong with the trivial aspects of it ;-)