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From:   Sami Tolvanen <samitolvanen@google.com>
Date:   Wed, 1 May 2019 10:00:10 -0700
Message-ID: <CABCJKudfkFB4QGp4J6E5r2Td+Wqw0dTYfMZkxVh9DgR7N=JwyA@mail.gmail.com>
Subject: Re: fix filler_t callback type mismatches
To:     Christoph Hellwig <hch@lst.de>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        linux-mtd@lists.infradead.org, linux-nfs@vger.kernel.org,
        linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
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On Wed, May 1, 2019 at 9:07 AM Christoph Hellwig <hch@lst.de> wrote:
>
> Casting mapping->a_ops->readpage to filler_t causes an indirect call
> type mismatch with Control-Flow Integrity checking. This change fixes
> the mismatch in read_cache_page_gfp and read_mapping_page by adding
> using a NULL filler argument as an indication to call ->readpage
> directly, and by passing the right parameter callbacks in nfs and jffs2.
>

Thanks, Christoph! This looks much cleaner.

I tested the patches on a kernel compiled with clang's -fsanitize=cfi
and the fixes look good to me. However, you missed one more type
mismatch in v9fs_vfs_readpages (fs/9p/vfs_addr.c). Could you please
add that one to the series too?

Sami