From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesper Dangaard Brouer Subject: Re: [PATCH] ipvsadm: catch the original errno from netlink answer Date: Fri, 11 Aug 2017 15:50:47 +0200 Message-ID: <20170811155047.46cb6b67@redhat.com> References: <20170805113828.9951-1-ja@ssi.bg> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170805113828.9951-1-ja@ssi.bg> Sender: lvs-devel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Julian Anastasov Cc: Simon Horman , lvs-devel@vger.kernel.org, lvs-users@linuxvirtualserver.org, Emanuele Rocca , brouer@redhat.com On Sat, 5 Aug 2017 14:38:28 +0300 Julian Anastasov wrote: > nl_recvmsgs_default() returns NLE_* error codes and not > errno values. As result, attempt to delete virtual service > returns NLE_OBJ_NOTFOUND (12) which matches the ENOMEM value. > > Problem as reported by Emanuele Rocca: > > ipvsadm -D -t example.org:80 > Memory allocation problem > > Fix it by providing generic error handler to catch the errno > value as returned in netlink answer. By this way all netlink > commands will get proper error string. The problem is present > only when ipvsadm is compiled with libnl. > > ipvsadm -D -t example.org:80 > No such service > > Reported-by: Emanuele Rocca > Signed-off-by: Julian Anastasov I've gone through the full call path from the kernel via netlink, and I was going to claim that we also needed to handle errno "-EEXIST" in the ipvsadm translation function ipvs_strerror(). Note, this fix uses the errno "-ESRCH". As kernel function ip_vs_del_service() return -EEXIST (if svc==NULL) http://elixir.free-electrons.com/linux/v4.12.5/source/net/netfilter/ipvs/ip_vs_ctl.c#L1480 BUT a closer look shows that -EEXIST will never get returned by ip_vs_del_service() as all callers of this function does a svc==NULL check and return "-ESRCH" instead. Thus, this patch is correct, but the kernel code is confusing ;-) Applied: https://git.kernel.org/pub/scm/utils/kernel/ipvsadm/ipvsadm.git/commit/?id=f8cff0808a24b -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer