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[2003:cb:c70b:4e00:3efc:1c60:bc60:f557]) by smtp.gmail.com with ESMTPSA id h20-20020a1ccc14000000b003b492753826sm1686070wmb.43.2022.10.25.00.05.34 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 25 Oct 2022 00:05:35 -0700 (PDT) Message-ID: Date: Tue, 25 Oct 2022 09:05:34 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.3.1 Subject: Re: [PATCH v1 1/7] selftests/vm: anon_cow: test COW handling of anonymous memory To: Rafael Mendonca Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Andrew Morton , Shuah Khan , Jason Gunthorpe , John Hubbard , Nadav Amit , Peter Xu , Andrea Arcangeli , Vlastimil Babka , Mike Rapoport , Christoph von Recklinghausen , Don Dutile References: <20220927110120.106906-1-david@redhat.com> <20220927110120.106906-2-david@redhat.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=AtGwgNSD; spf=pass (imf12.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1666681540; a=rsa-sha256; cv=none; b=pprGS6qjbmkr0ybsgtCoKPvqTy8KbnLBx1s9NeJ+uqlVZ0NWcRp9LKnEj5Li5OYjNAsDrg zDe6IH9qsMqK8TQFAtWfkT9N3itIAuRkqFLs8RBbzu7TJ0ud4QN3EpyfFKC2wEba6Jyi80 GufitjMyuEPUS3uL7ftH+GzeadGqywk= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1666681540; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=fe1WZpWI0+WNHlpXUbrxZSAOPfSw/3F9thWPXoPIAVs=; b=ZAdli2J9l0XNw9N1GvKR13DJ+t6ZmEaLnDXAdglaxWLeLXqLZ31gMxPy+fLqtkx+adw6OR tY1k2VCLNL6NoJj5Nrmi5HCclCOvD09mMXz6cT15w3Q07lAqFwjTR4AGTpfaB45htp74gI D1yMewU0amoTjU0u9xMOvfblzi0vgBA= X-Rspamd-Queue-Id: B3F094001A Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=AtGwgNSD; spf=pass (imf12.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspamd-Server: rspam02 X-Rspam-User: X-Stat-Signature: aimersdenowaqbwt8sckoq7q45o1y9bp X-HE-Tag: 1666681539-682288 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: >> + /* See if we still read the old values via the pipe. */ >> + for (total = 0; total < transferred; total += cur) { >> + cur = read(fds[0], new + total, transferred - total); >> + if (cur < 0) > > Hi David, > I was looking at some coccinelle reports for linux-next and > saw the following warning for this comparison: > > WARNING: Unsigned expression compared with zero: cur < 0 > > I think 'cur' needs to be of type 'ssize_t' for this comparison to work. > > The same warning is reported for the variable 'transferred' above, and > also for do_test_iouring() and do_test_vmsplice_in_parent() in > "selftests/vm: anon_cow: add liburing test cases". > Thanks for reporting! Indeed, we need a signed value. -- Thanks, David / dhildenb