From: "Darrick J. Wong" <djwong@kernel.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>,
brauner@kernel.org, cem@kernel.org, akpm@linux-foundation.org,
vbabka@kernel.org, surenb@google.com, mhocko@suse.com,
brendan.jackman@linux.dev, hannes@cmpxchg.org, ziy@nvidia.com,
david@kernel.org, qi.zheng@linux.dev, shakeel.butt@linux.dev,
ljs@kernel.org, linux-xfs@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
Yun Zhou <yun.zhou@windriver.com>
Subject: Re: [PATCH] xfs: fix NOFS state corruption in btree split worker
Date: Wed, 9 Sep 2026 23:07:05 -0700 [thread overview]
Message-ID: <20260910060705.GB6253@frogsfrogsfrogs> (raw)
In-Reply-To: <aqJEWmUN3Jsajoyl@infradead.org>
On Wed, Sep 09, 2026 at 10:47:06PM -0700, Christoph Hellwig wrote:
> Adding Yun Zhou, whoch touched this area recently.
>
> On Thu, Sep 03, 2026 at 09:37:56PM +0800, Kefeng Wang wrote:
> > xfs_btree_split_worker() calls xfs_trans_set_context() and
> > xfs_trans_clear_context() on the caller's transaction, overwriting
> > tp->t_pflags with the worker's NOFS state. When the caller already has
> > PF_MEMALLOC_NOFS set (e.g. xfs_end_ioend_write, xfs_dio_write_end_io),
> > the corrupted tp->t_pflags causes xfs_trans_free() to erroneously clear
> > the caller's NOFS protection.
> >
> > Use memalloc_nofs_save/restore with a local variable instead so
> > tp->t_pflags is never touched.
>
> Looks good:
>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
>
> Btw, if you have some spare time, it would be nice to kill
> xfs_trans_set_context/xfs_trans_clear_context as follow up given that
> they keep causing confusion.
Yes please, the wrappers have not been useful for making anyone's life
easier. :/
--D
next prev parent reply other threads:[~2026-09-10 6:07 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-02 13:16 [PATCH 0/4] mm: replace PF_KCOMPACTD/PF_KSWAPD with kthread_func() Kefeng Wang
2026-09-02 13:16 ` [PATCH 1/4] xfs: remove dead kswapd flag inheritance from btree split worker Kefeng Wang
2026-09-02 14:32 ` Christoph Hellwig
2026-09-02 15:33 ` Shakeel Butt
2026-09-02 13:16 ` [PATCH 2/4] iomap: simplify writepages reclaim guard Kefeng Wang
2026-09-02 14:32 ` Christoph Hellwig
2026-09-03 13:46 ` Kefeng Wang
2026-09-02 15:34 ` Shakeel Butt
2026-09-02 13:16 ` [PATCH 3/4] mm: replace PF_KSWAPD flag with kthread_func() check Kefeng Wang
2026-09-02 15:36 ` Shakeel Butt
2026-09-02 16:35 ` Vlastimil Babka (SUSE)
2026-09-02 16:39 ` Zi Yan
2026-09-10 11:56 ` David Hildenbrand (Arm)
2026-09-02 13:16 ` [PATCH 4/4] mm: replace PF_KCOMPACTD " Kefeng Wang
2026-09-02 15:37 ` Shakeel Butt
2026-09-02 16:36 ` Vlastimil Babka (SUSE)
2026-09-02 16:40 ` Zi Yan
2026-09-10 11:57 ` David Hildenbrand (Arm)
2026-09-02 15:31 ` [PATCH 0/4] mm: replace PF_KCOMPACTD/PF_KSWAPD with kthread_func() Shakeel Butt
2026-09-02 20:44 ` Andrew Morton
2026-09-03 13:37 ` [PATCH] xfs: fix NOFS state corruption in btree split worker Kefeng Wang
2026-09-03 13:52 ` Brian Foster
2026-09-04 0:41 ` Kefeng Wang
2026-09-04 11:57 ` Brian Foster
2026-09-10 5:47 ` Christoph Hellwig
2026-09-10 6:07 ` Darrick J. Wong [this message]
[not found] ` <20260910140742.833170-1-wangkefeng.wang@huawei.com>
[not found] ` <aqLqeTsbKBMEsl-G@bfoster>
2026-09-11 0:57 ` [PATCH] xfs: kill xfs_trans_set/clear_context() helpers Kefeng Wang
2026-09-11 7:12 ` Christoph Hellwig
2026-09-11 10:51 ` Kefeng Wang
2026-09-03 13:40 ` [PATCH 0/4] mm: replace PF_KCOMPACTD/PF_KSWAPD with kthread_func() Kefeng Wang
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