From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1YnLaI-0007Qd-8T for mharc-qemu-trivial@gnu.org; Wed, 29 Apr 2015 02:35:02 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54837) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YnLaF-0007MB-PI for qemu-trivial@nongnu.org; Wed, 29 Apr 2015 02:35:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YnLaE-00068f-UR for qemu-trivial@nongnu.org; Wed, 29 Apr 2015 02:34:59 -0400 Received: from isrv.corpit.ru ([86.62.121.231]:39017) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YnLa8-00065e-99; Wed, 29 Apr 2015 02:34:52 -0400 Received: from [192.168.88.2] (mjt.vpn.tls.msk.ru [192.168.177.99]) by isrv.corpit.ru (Postfix) with ESMTP id 9699442A54; Wed, 29 Apr 2015 09:34:51 +0300 (MSK) Message-ID: <55407B8B.1010803@msgid.tls.msk.ru> Date: Wed, 29 Apr 2015 09:34:51 +0300 From: Michael Tokarev Organization: Telecom Service, JSC User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.6.0 MIME-Version: 1.0 To: Thomas Huth , qemu-devel@nongnu.org References: <1430153944-24368-1-git-send-email-thuth@redhat.com> In-Reply-To: <1430153944-24368-1-git-send-email-thuth@redhat.com> OpenPGP: id=804465C5 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 86.62.121.231 Cc: qemu-trivial@nongnu.org, Paolo Bonzini Subject: Re: [Qemu-trivial] [PATCH] kvm: Silence warning from valgrind X-BeenThere: qemu-trivial@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 29 Apr 2015 06:35:00 -0000 27.04.2015 19:59, Thomas Huth wrote: > valgrind complains here about uninitialized bytes with the following message: > > ==17814== Syscall param ioctl(generic) points to uninitialised byte(s) > ==17814== at 0x466A780: ioctl (in /usr/lib64/power8/libc-2.17.so) > ==17814== by 0x100735B7: kvm_vm_ioctl (kvm-all.c:1920) > ==17814== by 0x10074583: kvm_set_ioeventfd_mmio (kvm-all.c:574) > > Let's fix it by using a proper struct initializer in kvm_set_ioeventfd_mmio(). > > Signed-off-by: Thomas Huth > --- > kvm-all.c | 14 +++++++------- > 1 file changed, 7 insertions(+), 7 deletions(-) > > diff --git a/kvm-all.c b/kvm-all.c > index dd44f8c..077b0ed 100644 > --- a/kvm-all.c > +++ b/kvm-all.c > @@ -552,13 +552,13 @@ static int kvm_set_ioeventfd_mmio(int fd, hwaddr addr, uint32_t val, > bool assign, uint32_t size, bool datamatch) > { > int ret; > - struct kvm_ioeventfd iofd; > - > - iofd.datamatch = datamatch ? adjust_ioeventfd_endianness(val, size) : 0; > - iofd.addr = addr; > - iofd.len = size; > - iofd.flags = 0; > - iofd.fd = fd; > + struct kvm_ioeventfd iofd = { > + .datamatch = datamatch ? adjust_ioeventfd_endianness(val, size) : 0, > + .addr = addr, > + .len = size, > + .flags = 0, > + .fd = fd, > + }; Hm. So, what's the difference? The same fields are assigned the same values, why in first case we have some uninitialized data and in second case everything is initialized? Does struct initializer zero-fills all other places (alignments, missing fields etc) ? If yes, there's no need to assign zero to flags, btw ;) Thanks, /mjt From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54818) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YnLaE-0007M4-2i for qemu-devel@nongnu.org; Wed, 29 Apr 2015 02:34:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YnLa8-000667-G2 for qemu-devel@nongnu.org; Wed, 29 Apr 2015 02:34:58 -0400 Message-ID: <55407B8B.1010803@msgid.tls.msk.ru> Date: Wed, 29 Apr 2015 09:34:51 +0300 From: Michael Tokarev MIME-Version: 1.0 References: <1430153944-24368-1-git-send-email-thuth@redhat.com> In-Reply-To: <1430153944-24368-1-git-send-email-thuth@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [Qemu-trivial] [PATCH] kvm: Silence warning from valgrind List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth , qemu-devel@nongnu.org Cc: qemu-trivial@nongnu.org, Paolo Bonzini 27.04.2015 19:59, Thomas Huth wrote: > valgrind complains here about uninitialized bytes with the following message: > > ==17814== Syscall param ioctl(generic) points to uninitialised byte(s) > ==17814== at 0x466A780: ioctl (in /usr/lib64/power8/libc-2.17.so) > ==17814== by 0x100735B7: kvm_vm_ioctl (kvm-all.c:1920) > ==17814== by 0x10074583: kvm_set_ioeventfd_mmio (kvm-all.c:574) > > Let's fix it by using a proper struct initializer in kvm_set_ioeventfd_mmio(). > > Signed-off-by: Thomas Huth > --- > kvm-all.c | 14 +++++++------- > 1 file changed, 7 insertions(+), 7 deletions(-) > > diff --git a/kvm-all.c b/kvm-all.c > index dd44f8c..077b0ed 100644 > --- a/kvm-all.c > +++ b/kvm-all.c > @@ -552,13 +552,13 @@ static int kvm_set_ioeventfd_mmio(int fd, hwaddr addr, uint32_t val, > bool assign, uint32_t size, bool datamatch) > { > int ret; > - struct kvm_ioeventfd iofd; > - > - iofd.datamatch = datamatch ? adjust_ioeventfd_endianness(val, size) : 0; > - iofd.addr = addr; > - iofd.len = size; > - iofd.flags = 0; > - iofd.fd = fd; > + struct kvm_ioeventfd iofd = { > + .datamatch = datamatch ? adjust_ioeventfd_endianness(val, size) : 0, > + .addr = addr, > + .len = size, > + .flags = 0, > + .fd = fd, > + }; Hm. So, what's the difference? The same fields are assigned the same values, why in first case we have some uninitialized data and in second case everything is initialized? Does struct initializer zero-fills all other places (alignments, missing fields etc) ? If yes, there's no need to assign zero to flags, btw ;) Thanks, /mjt