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[83.57.169.13]) by smtp.gmail.com with ESMTPSA id v6sm7880773wrx.32.2021.01.28.10.07.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 28 Jan 2021 10:07:52 -0800 (PST) Subject: Re: [PATCH] migration/qemu-file: Fix maybe uninitialized on qemu_get_buffer_in_place() To: "Dr. David Alan Gilbert" , Wainer dos Santos Moschetta References: <20210128130625.569900-1-wainersm@redhat.com> <20210128171619.GF2951@work-vm> From: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= Message-ID: Date: Thu, 28 Jan 2021 19:07:51 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20210128171619.GF2951@work-vm> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=philmd@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=63.128.21.124; envelope-from=philmd@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.252, 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_H4=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: Thomas Huth , qemu-devel@nongnu.org, quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 1/28/21 6:16 PM, Dr. David Alan Gilbert wrote: > * Wainer dos Santos Moschetta (wainersm@redhat.com) wrote: >> Fixed error when compiling migration/qemu-file.c with -Werror=maybe-uninitialized >> as shown here: >> >> ../migration/qemu-file.c: In function 'qemu_get_buffer_in_place': >> ../migration/qemu-file.c:604:18: error: 'src' may be used uninitialized in this function [-Werror=maybe-uninitialized] >> 604 | *buf = src; >> | ~~~~~^~~~~ >> cc1: all warnings being treated as errors >> >> Signed-off-by: Wainer dos Santos Moschetta > > Yes, I think I had a discussion with someone about this recently but > can't find it; Maybe with Thomas, he reported that 2 years ago when building with -O3: https://www.mail-archive.com/qemu-devel@nongnu.org/msg599522.html > the compiler is technically correct, but the only time > it's unitialised is the case where it's result doesn't matter. > > Still, to shut the compiler up: > > > Reviewed-by: Dr. David Alan Gilbert > >> --- >> Passed on CI: https://gitlab.com/wainersm/qemu/-/pipelines/247801576 >> >> migration/qemu-file.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/migration/qemu-file.c b/migration/qemu-file.c >> index be21518c57..d6e03dbc0e 100644 >> --- a/migration/qemu-file.c >> +++ b/migration/qemu-file.c >> @@ -595,7 +595,7 @@ size_t qemu_get_buffer_in_place(QEMUFile *f, uint8_t **buf, size_t size) >> { >> if (size < IO_BUF_SIZE) { >> size_t res; >> - uint8_t *src; >> + uint8_t *src = NULL; >> >> res = qemu_peek_buffer(f, &src, size, 0); >> >> -- >> 2.28.0 >>