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Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20240821024301.1058918-9-wozizhi@huawei.com> References: <20240821024301.1058918-9-wozizhi@huawei.com> <20240821024301.1058918-1-wozizhi@huawei.com> To: Zizhi Wo Cc: dhowells@redhat.com, netfs@lists.linux.dev, jlayton@kernel.org, hsiangkao@linux.alibaba.com, jefflexu@linux.alibaba.com, zhujia.zj@bytedance.com, linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, libaokun1@huawei.com, yangerkun@huawei.com, houtao1@huawei.com, yukuai3@huawei.com Subject: Re: [PATCH 8/8] netfs/fscache: Add a memory barrier for FSCACHE_VOLUME_CREATING Precedence: bulk X-Mailing-List: netfs@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <303925.1728559457.1@warthog.procyon.org.uk> Content-Transfer-Encoding: quoted-printable Date: Thu, 10 Oct 2024 12:24:17 +0100 Message-ID: <303926.1728559457@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Zizhi Wo wrote: > In fscache_create_volume(), there is a missing memory barrier between th= e > bit-clearing operation and the wake-up operation. This may cause a > situation where, after a wake-up, the bit-clearing operation hasn't been > detected yet, leading to an indefinite wait. The triggering process is a= s > follows: > ... > By combining the clear and wake operations into clear_and_wake_up_bit() = to > fix this issue. > = > Fixes: bfa22da3ed65 ("fscache: Provide and use cache methods to lookup/c= reate/free a volume") > Signed-off-by: Zizhi Wo Acked-by: David Howells