From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Matthew Wilcox <willy@infradead.org>
Cc: Josef Bacik <josef@toxicpanda.com>,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org
Subject: Re: filemap_fault can lose errors
Date: Wed, 11 Sep 2019 18:23:38 +0300 [thread overview]
Message-ID: <20190911152338.gqqgxrmqycodfocb@box> (raw)
In-Reply-To: <20190911025158.GG29434@bombadil.infradead.org>
On Tue, Sep 10, 2019 at 07:51:58PM -0700, Matthew Wilcox wrote:
>
> If we encounter an error on a page, we can lose the error if we've
> dropped the mmap_sem while we wait for the I/O. That can result in
> taking the fault multiple times, and retrying the read multiple times.
> Spotted by inspection.
But does the patch make any difference?
Looking into x86 code, VM_FAULT_RETRY makes it retry the fault or return
to userspace before it checks for VM_FAULT_SIGBUS bit.
--
Kirill A. Shutemov
prev parent reply other threads:[~2019-09-11 15:23 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-11 2:51 filemap_fault can lose errors Matthew Wilcox
2019-09-11 15:23 ` Kirill A. Shutemov [this message]
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