linux-kernel - Re: Fix potential data loss and corruption due to Incorrect BIO Chain Handling

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Message-ID: <CANubcdVhDZ+G5brj6g+mBBOHLyeyM9gWaLJ+EKwyWXJjSoi1SQ@mail.gmail.com>
Date: Fri, 28 Nov 2025 09:29:52 +0800
From: Stephen Zhang <starzhangzsd@...il.com>
To: Christoph Hellwig <hch@...radead.org>
Cc: Ming Lei <ming.lei@...hat.com>, Andreas Gruenbacher <agruenba@...hat.com>, 
	linux-kernel@...r.kernel.org, linux-block@...r.kernel.org, 
	nvdimm@...ts.linux.dev, virtualization@...ts.linux.dev, 
	linux-nvme@...ts.infradead.org, gfs2@...ts.linux.dev, ntfs3@...ts.linux.dev, 
	linux-xfs@...r.kernel.org, zhangshida@...inos.cn
Subject: Re: Fix potential data loss and corruption due to Incorrect BIO Chain Handling

Christoph Hellwig <hch@...radead.org> 于2025年11月27日周四 15:17写道：
>
> On Thu, Nov 27, 2025 at 03:05:29PM +0800, Stephen Zhang wrote:
> > No, they are not using bcache.
>
> Then please figure out how bio_chain_endio even gets called in this
> setup.  I think for mainline the approach should be to fix bcache
> and eorfs to not call into ->bi_end_io and add a BUG_ON() to
> bio_chain_endio to ensure no new callers appear.  I
>

Okay, thanks for the suggestion.

> > If there are no further objections or other insights regarding this issue,
> > I will proceed with creating a v2 of this series.
>
> Not sure how that is helpful.  You have a problem on a kernel from stone
> age, can't explain what actually happens and propose something that is
> mostly a no-op in mainline, with the callers that could even reach the
> area being clear API misuse.
>

Analysis of the 4.19 kernel bug confirmed it was not caused by the
->bi_end_io call. Instead, this investigation led us to discover a different bug
in the upstream kernel. The v2 patch series is dedicated to fixing this newly
found upstream issue.

Thanks,
shida
>