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[195.135.220.15]) by mx.google.com with ESMTPS id c58si1998020ede.408.2019.06.13.02.33.04 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 13 Jun 2019 02:33:04 -0700 (PDT) Received-SPF: pass (google.com: domain of rpenyaev@suse.de designates 195.135.220.15 as permitted sender) client-ip=195.135.220.15; Authentication-Results: mx.google.com; spf=pass (google.com: domain of rpenyaev@suse.de designates 195.135.220.15 as permitted sender) smtp.mailfrom=rpenyaev@suse.de X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 3ECB3AF22; Thu, 13 Jun 2019 09:33:03 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Thu, 13 Jun 2019 11:33:02 +0200 From: Roman Penyaev To: Anshuman Khandual Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Rick Edgecombe , Andrey Ryabinin , Mike Rapoport , Roman Gushchin , Michal Hocko , "Uladzislau Rezki (Sony)" , Andrew Morton Subject: Re: [PATCH] mm/vmalloc: Check absolute error return from vmap_[p4d|pud|pmd|pte]_range() In-Reply-To: <1560413551-17460-1-git-send-email-anshuman.khandual@arm.com> References: <1560413551-17460-1-git-send-email-anshuman.khandual@arm.com> Message-ID: <7cc6a46c50c2008bfb968c5e48af5a49@suse.de> X-Sender: rpenyaev@suse.de User-Agent: Roundcube Webmail 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 2019-06-13 10:12, Anshuman Khandual wrote: > vmap_pte_range() returns an -EBUSY when it encounters a non-empty PTE. > But > currently vmap_pmd_range() unifies both -EBUSY and -ENOMEM return code > as > -ENOMEM and send it up the call chain which is wrong. Interestingly > enough > vmap_page_range_noflush() tests for the absolute error return value > from > vmap_p4d_range() but it does not help because -EBUSY has been merged > with > -ENOMEM. So all it can return is -ENOMEM. Fix this by testing for > absolute > error return from vmap_pmd_range() all the way up to vmap_p4d_range(). I could not find any real external caller of vmap API who really cares about the errno, and frankly why they should? This is allocation path, allocation failed - game over. When you step on -EBUSY case something has gone completely wrong in your kernel, you get a big warning in your dmesg and it is already does not matter what errno you get. -- Roman