linux-ext4 - Re: [PATCH 2/7] mm: Protect operations adding pages to page cache with i_mapping

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20210413125746.GB1366579@infradead.org>
Date:   Tue, 13 Apr 2021 13:57:46 +0100
From:   Christoph Hellwig <hch@...radead.org>
To:     Jan Kara <jack@...e.cz>
Cc:     linux-fsdevel@...r.kernel.org, linux-ext4@...r.kernel.org,
        linux-xfs@...r.kernel.org, Ted Tso <tytso@....edu>,
        Christoph Hellwig <hch@...radead.org>,
        Amir Goldstein <amir73il@...il.com>,
        Dave Chinner <david@...morbit.com>
Subject: Re: [PATCH 2/7] mm: Protect operations adding pages to page cache
 with i_mapping_lock

>  	if (error == AOP_TRUNCATED_PAGE)
>  		put_page(page);
> +	up_read(&mapping->host->i_mapping_sem);
>  	return error;

Please add an unlock_mapping label above this up_read and consolidate
most of the other unlocks by jumping there (put_and_wait_on_page_locked
probablt can't use it).

>  truncated:
>  	unlock_page(page);
> @@ -2309,6 +2324,7 @@ static int filemap_update_page(struct kiocb *iocb,
>  	return AOP_TRUNCATED_PAGE;

The trunated case actually seems to miss the unlock.

Similarly I think filemap_fault would benefit from a common
unlock path.