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Sat, 09 Nov 2019 15:05:27 -0800 (PST) Date: Sun, 10 Nov 2019 04:35:20 +0530 From: Jeffrin Jose To: davem@davemloft.net, willemb@google.com, xiyou.wangcong@gmail.com, fw@strlen.de, jakub.kicinski@netronome.com, john.hurley@netronome.com, pabeni@redhat.com, brouer@redhat.com, bigeasy@linutronix.de, jonathan.lemon@gmail.com, edumazet@google.com Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: objtool: skb_push.cold()+0x15: unreachable instruction Message-ID: <20191109230520.GA22258@debian> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org hello, i got a warning during kernel compilation. net/core/skbuff.o: warning: objtool: skb_push.cold()+0x15: unreachable instruction related clips... --------------------x----------------x--------------------- (gdb) l skb_push.cold 1880 void *skb_push(struct sk_buff *skb, unsigned int len) 1881 { 1882 skb->data -= len; 1883 skb->len += len; 1884 if (unlikely(skb->data < skb->head)) 1885 skb_under_panic(skb, len, __builtin_return_address(0)); 1886 return skb->data; 1887 } 1888 EXPORT_SYMBOL(skb_push); 1889 (gdb) l *0xffffffff815ffc8e 0xffffffff815ffc8e is in skb_push (net/core/skbuff.c:1885). 1880 void *skb_push(struct sk_buff *skb, unsigned int len) 1881 { 1882 skb->data -= len; 1883 skb->len += len; 1884 if (unlikely(skb->data < skb->head)) 1885 skb_under_panic(skb, len, __builtin_return_address(0)); 1886 return skb->data; 1887 } 1888 EXPORT_SYMBOL(skb_push); 1889 (gdb) ------------------x-----------------------x------------------------------------ $uname -a Linux debian 5.4.0-rc1+ #1 SMP Sat Nov 9 21:29:48 IST 2019 x86_64 GNU/Linux $ this kernel is from linux-kselftest tree ---------------------------x-------------x------------------------------ $gcc --version gcc (Debian 9.2.1-14) 9.2.1 20191025 Copyright (C) 2019 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. -------------------------x-------------------x----------------------------- Linux debian 5.4.0-rc1+ #1 SMP Sat Nov 9 21:29:48 IST 2019 x86_64 GNU/Linux GNU Make 4.2.1 Binutils 2.33.1 Util-linux 2.33.1 Mount 2.33.1 Linux C Library 2.29 Dynamic linker (ldd) 2.29 Procps 3.3.15 Kbd 2.0.4 Console-tools 2.0.4 Sh-utils 8.30 Udev 241 -------------------------------x-----------------x---------------------------- -- software engineer rajagiri school of engineering and technology