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imf13.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf13.hostedemail.com: domain of hch@lst.de designates 213.95.11.211 as permitted sender) smtp.mailfrom=hch@lst.de ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1705071299; a=rsa-sha256; cv=none; b=3qSpixzqg8a93ORctSzC1NU+PLbH93puXc6zRXd3Tjls7wK0u+7PUym+pr6GVN2fHt6iLE 0ybe+kbCLDcMrfRiPsuCCscjb1p/D+fCfgxXB9lQjiU+LDbGyWOIGMvca0Wj55i99qWH2N oLjvCK80J60kL7jcg++kcl2snUyp5ro= Received: by verein.lst.de (Postfix, from userid 2407) id 79EAD68CFE; Fri, 12 Jan 2024 15:54:53 +0100 (CET) Date: Fri, 12 Jan 2024 15:54:53 +0100 From: Christoph Hellwig To: Matthew Wilcox Cc: David Howells , "Jitindar Singh, Suraj" , "rohiths.msft@gmail.com" , "gregkh@linuxfoundation.org" , "linux-mm@kvack.org" , "stfrench@microsoft.com" , "pc@manguebit.com" , "jlayton@kernel.org" , "nspmangalore@gmail.com" , "stable-commits@vger.kernel.org" , Christoph Hellwig Subject: Re: Patch "cifs: Fix flushing, invalidation and file size with copy_file_range()" has been added to the 6.1-stable tree Message-ID: <20240112145453.GA8959@lst.de> References: <2023121124-trifle-uncharted-2622@gregkh> <2161774.1705069315@warthog.procyon.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-Rspamd-Queue-Id: AE1D720024 X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: zdoxy84hcfdut8fm5bj3b9hn63fb3d55 X-HE-Tag: 1705071298-123193 X-HE-Meta: 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 fPmd7c6i 36knHfHTivScYtcMri7aKW7mKJsdWQm+rspN2jAISSRb/xKQmxoh4gjSusUNBvCKw+bBL1Lrh4ivvWQWuJyPkLUoTVl0rE8ewbQkcPVv5XKIB/IVTqkdb845NQx2XPXU/S4uNDnLn0rHsEZ9k9/ChzxVmwYyA04givyiQfsmRmaZM9ugChHbUyF/AhLX2Ftn1ktZsvzxVLNW+3nzxC3BnJusxmcQErE+WXunHwjf0ASaudgrEOqwBuPc9nh+QpOjZkgzr X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Jan 12, 2024 at 02:44:35PM +0000, Matthew Wilcox wrote: > On Fri, Jan 12, 2024 at 02:21:55PM +0000, David Howells wrote: > > Jitindar Singh, Suraj wrote: > > > > > When testing the v6.1.69 kernel I bisected an issue to the below commit > > > which was added in v6.1.68. When running the xfstests[1] on cifs I > > > observe a null pointer dereference in cifs_flush_folio() because folio > > > is null and dereferenced in size = folio_size(folio). > > > > Yeah. __filemap_get_folio() works differently in v6.1.y. There it returns a > > Let's cc hch so he's aware of how much pain this change caused. > > Never change function semantics without changing its name or arguments. Maybe the maintainer should have pushed back if he feels strongly about that? That being said backporting any fs code without first having done a QA run just feels horribly dangerous to start with. People need to stop doing that.