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[198.145.29.99]) by mx.google.com with ESMTPS id y11si11856288plr.381.2019.06.17.21.26.07 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 17 Jun 2019 21:26:07 -0700 (PDT) Received-SPF: pass (google.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) client-ip=198.145.29.99; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=R6ur39y7; spf=pass (google.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org Received: from localhost.localdomain (c-73-223-200-170.hsd1.ca.comcast.net [73.223.200.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 854072084D; Tue, 18 Jun 2019 04:26:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560831967; bh=xv/fCdFQ6SfbaJzNr+4Vp5gITAmLP6lf4CXGPgHSad8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=R6ur39y7TUbCZ9I9GPNBpsgEq0A7kXynJU20VbzOQGtqant4HGaLMKo1/Qfhk7cr7 tde33KHi5Y7TxhTaqqC6+HziktP/p9+akYAS8ke5AZ3GOrAwOuR0iaD1yngtP6A7Zt xKHocsz345eJckm197hPRlWYwLgBSR8v5C1arUzU= Date: Mon, 17 Jun 2019 21:26:05 -0700 From: Andrew Morton To: Nadav Amit Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org, Borislav Petkov , Toshi Kani , Peter Zijlstra , Dave Hansen , Dan Williams , Bjorn Helgaas , Ingo Molnar Subject: Re: [PATCH 1/3] resource: Fix locking in find_next_iomem_res() Message-Id: <20190617212605.bb8cc4571ee67879033e1bc4@linux-foundation.org> In-Reply-To: <20190613045903.4922-2-namit@vmware.com> References: <20190613045903.4922-1-namit@vmware.com> <20190613045903.4922-2-namit@vmware.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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: On Wed, 12 Jun 2019 21:59:01 -0700 Nadav Amit wrote: > Since resources can be removed, locking should ensure that the resource > is not removed while accessing it. However, find_next_iomem_res() does > not hold the lock while copying the data of the resource. Looks right to me. > Keep holding the lock while the data is copied. While at it, change the > return value to a more informative value. It is disregarded by the > callers. The kerneldoc needs a resync: --- a/kernel/resource.c~resource-fix-locking-in-find_next_iomem_res-fix +++ a/kernel/resource.c @@ -326,7 +326,7 @@ EXPORT_SYMBOL(release_resource); * * If a resource is found, returns 0 and @*res is overwritten with the part * of the resource that's within [@start..@end]; if none is found, returns - * -1 or -EINVAL for other invalid parameters. + * -ENODEV. Returns -EINVAL for invalid parameters. * * This function walks the whole tree and not just first level children * unless @first_lvl is true. _