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([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id x11sm3571766wme.9.2021.03.18.10.34.16 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 18 Mar 2021 10:34:17 -0700 (PDT) Subject: Re: [PATCH for 6.0 v3] hw/intc/i8259: Refactor pic_read_irq() to avoid uninitialized variable To: Christian Borntraeger , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , qemu-devel@nongnu.org References: <20210318163059.3686596-1-philmd@redhat.com> From: Paolo Bonzini Message-ID: <32a0250b-6d09-e092-af22-939fd5295cf6@redhat.com> Date: Thu, 18 Mar 2021 18:34:16 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=pbonzini@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.249, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 18/03/21 17:34, Christian Borntraeger wrote: >> Some compiler versions are smart enough to detect a potentially >> uninitialized variable, but are not smart enough to detect that this >> cannot happen due to the code flow: >> >> ../hw/intc/i8259.c: In function ‘pic_read_irq’: >> ../hw/intc/i8259.c:203:13: error: ‘irq2’ may be used uninitialized in this function [-Werror=maybe-uninitialized] >> 203 | irq = irq2 + 8; >> | ~~~~^~~~~~~~~~ >> >> Restrict irq2 variable use to the inner statement. >> >> Fixes: 78ef2b6989f ("i8259: Reorder intack in pic_read_irq") >> Reported-by: Christian Borntraeger >> Signed-off-by: Philippe Mathieu-Daudé > Tested-by: Christian Borntraeger Queued, thanks to both.