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

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Message-ID: <aSf6T6z6f2YqQRPH@infradead.org>
Date: Wed, 26 Nov 2025 23:14:23 -0800
From: Christoph Hellwig <hch@...radead.org>
To: Stephen Zhang <starzhangzsd@...il.com>
Cc: Christoph Hellwig <hch@...radead.org>, 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

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

> 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.