From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1516382199; cv=none; d=google.com; s=arc-20160816; b=E21I3+8zl8afnm4rpa/cSu18jravUCBzOqheKRFZFnjHPh+rp0/9DZ91sb33ZBVqwJ xolYMuzcAONRYnzC19sOQZv8YB9g32ROVjAA+DKeb5+rivGCCKYlVcvINA/MMqEpRxZT oRD04wGCJUPnyTYbH7mj3nwG+nFcI98Sessg5ktJxtkB7/j7LmaMdKF9xKej9AqiMeZN P727Bj8JJ+5VloLcf88BGzgGaloheFZU54hIOrNytCwVvoSLpPmhuIYjbPTYOx896EQr zXl3Cgo+JH9gYi7aI56+mwkj9ebQp4cwRTkL8+JU1cjFJbFDU2ip1tHCghUbDKz9NfBR YVDA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:sender:dkim-signature :arc-authentication-results; bh=e+42sYQc7Y+YIpCJT3NnNLxrhssWIQ9gO582Evushd8=; b=q2/lyPd3XzQGuRcC+vSEAOyqx8X9zcha6XPJ/fU3hTq0tLkcnE40kZpqMatXElWeDT OWWN4J04XsVc22q8Yfic9TznmNHx1eDIMSocD2Ft31s2Zk3IYM0xXZfAiF9ukcr0Kxvm ApVgCuvKbqrqXMypTysIuFiPNJgWD7MwiawaAIOQqKsH0tF3O/Ol3pl78mIFo+C4XlGo ciC9ziqHWH7UraF9YBciUq/a65kCvHaWvNZa3Rfh4U/Sa/WD1kHYYn4JF2HqgO6Pf+I2 UZWmGtqTHofkroURUAQgFjDEEto1Eq8HwNE/6aQQStQBsJZ7Z1nfNY1JcNr0YVH4NFK3 x7/Q== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=XtjQ+pDs; spf=pass (google.com: domain of htejun@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=htejun@gmail.com Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=XtjQ+pDs; spf=pass (google.com: domain of htejun@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=htejun@gmail.com X-Google-Smtp-Source: ACJfBouCDvOStvuRS5zMHC7GGGCuv662ej4hBQYn0w9QfdU/gzrjoJeOzn9Jx3THbU13UwjIYENsgA== Sender: Tejun Heo Date: Fri, 19 Jan 2018 09:16:36 -0800 From: Tejun Heo To: Ivan Vecera Cc: linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org, viro@zeniv.linux.org.uk Subject: Re: [PATCH driver-core] kernfs: fix regression in kernfs_fop_write caused by wrong type Message-ID: <20180119171636.GE3460072@devbig577.frc2.facebook.com> References: <20180119081854.13609-1-ivecera@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180119081854.13609-1-ivecera@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1590008152180270660?= X-GMAIL-MSGID: =?utf-8?q?1590041981025656940?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Fri, Jan 19, 2018 at 09:18:54AM +0100, Ivan Vecera wrote: > Commit b7ce40cff0b9 ("kernfs: cache atomic_write_len in > kernfs_open_file") changes type of local variable 'len' from ssize_t > to size_t. This change caused that the *ppos value is updated also > when the previous write callback failed. > > Mentioned snippet: > ... > len = ops->write(...); <- return value can be negative > ... > if (len > 0) <- true here in this case > *ppos += len; > ... > > Fixes: b7ce40cff0b9 ("kernfs: cache atomic_write_len in kernfs_open_file") > Signed-off-by: Ivan Vecera Oops. Acked-by: Tejun Heo Thanks. -- tejun