compile failure: taking address of packed member of may result in an unaligned pointer value

[WinnieeBear]

Describe your issue

compile failure on ubuntu: taking address of packed member of may result in an unaligned pointer value

• Is this a bug report or a feature request?
  bug report
• Describe the issue
  compile failure
• What is the expected behaviour?
  compile success
• How to reproduce the problem?
  under ubuntu 20.04, run command make all will reproduce this issue.

error logs:

❯ make all
cc  -I include -Wall -Werror -pthread -c src/skbuff.c -o build/skbuff.o
cc  -I include -Wall -Werror -pthread -c src/socket.c -o build/socket.o
cc  -I include -Wall -Werror -pthread -c src/ip_input.c -o build/ip_input.o
cc  -I include -Wall -Werror -pthread -c src/tuntap_if.c -o build/tuntap_if.o
cc  -I include -Wall -Werror -pthread -c src/icmpv4.c -o build/icmpv4.o
cc  -I include -Wall -Werror -pthread -c src/netdev.c -o build/netdev.o
cc  -I include -Wall -Werror -pthread -c src/tcp.c -o build/tcp.o
cc  -I include -Wall -Werror -pthread -c src/cli.c -o build/cli.o
cc  -I include -Wall -Werror -pthread -c src/tcp_data.c -o build/tcp_data.o
cc  -I include -Wall -Werror -pthread -c src/sock.c -o build/sock.o
cc  -I include -Wall -Werror -pthread -c src/tcp_output.c -o build/tcp_output.o
cc  -I include -Wall -Werror -pthread -c src/arp.c -o build/arp.o
cc  -I include -Wall -Werror -pthread -c src/route.c -o build/route.o
cc  -I include -Wall -Werror -pthread -c src/ipc.c -o build/ipc.o
src/ipc.c: In function ‘ipc_connect’:
src/ipc.c:164:41: error: taking address of packed member of ‘struct ipc_connect’ may result in an unaligned pointer value [-Werror=address-of-packed-member]
  164 |     rc = _connect(pid, payload->sockfd, &payload->addr, payload->addrlen);
      |                                         ^~~~~~~~~~~~~~
src/ipc.c: In function ‘ipc_getsockopt’:
src/ipc.c:275:79: error: taking address of packed member of ‘struct ipc_sockopt’ may result in an unaligned pointer value [-Werror=address-of-packed-member]
  275 |     rc = _getsockopt(pid, opts->fd, opts->level, opts->optname, opts->optval, &opts->optlen);
      |                                                                               ^~~~~~~~~~~~~
cc1: all warnings being treated as errors
make: *** [Makefile:15: build/ipc.o] Error 1
❯ gcc --version
gcc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0
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.

Describe your running environment

This is important for troubleshooting. Please attach at least the following info:

• OS (e.g. cat /etc/os-release):
• ❯ cat /etc/os-release
  NAME="Ubuntu"
  VERSION="20.04.2 LTS (Focal Fossa)"
  ID=ubuntu
  ID_LIKE=debian
  PRETTY_NAME="Ubuntu 20.04.2 LTS"
  VERSION_ID="20.04"
  HOME_URL="https://www.ubuntu.com/"
  SUPPORT_URL="https://help.ubuntu.com/"
  BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
  PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
  VERSION_CODENAME=focal
  UBUNTU_CODENAME=focal
• Kernel (e.g. uname -a):
• ❯ uname -a
  Linux ubuntu 5.8.0-55-generic #62~20.04.1-Ubuntu SMP Wed Jun 2 08:55:04 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

[Basty9]

Same issue here:

cc  -I include -Wall -Werror -pthread -c src/ipc.c -o build/ipc.o
src/ipc.c: In function ‘ipc_connect’:
src/ipc.c:164:41: error: taking address of packed member of ‘struct ipc_connect’ may result in an unaligned pointer value [-Werror=address-of-packed-member]
  164 |     rc = _connect(pid, payload->sockfd, &payload->addr, payload->addrlen);
      |                                         ^~~~~~~~~~~~~~
src/ipc.c: In function ‘ipc_getsockopt’:
src/ipc.c:275:79: error: taking address of packed member of ‘struct ipc_sockopt’ may result in an unaligned pointer value [-Werror=address-of-packed-member]
  275 |     rc = _getsockopt(pid, opts->fd, opts->level, opts->optname, opts->optval, &opts->optlen);
      |                                                                               ^~~~~~~~~~~~~
cc1: all warnings being treated as errors
make: *** [Makefile:15: build/ipc.o] Error 1

NAME="Ubuntu"
VERSION="20.04.2 LTS (Focal Fossa)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 20.04.2 LTS"
VERSION_ID="20.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=focal
UBUNTU_CODENAME=focal

Linux ubuntu 5.8.0-59-generic #66~20.04.1-Ubuntu SMP Thu Jun 17 11:14:10 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

[ludeen007]

just remove "-Werror" from "CPPFLAGS" in Makefile file.

[minghu6]

just remove "-Werror" from "CPPFLAGS" in Makefile file.

just add -Wno-address-of-packed-member