[LU-12822] gcc9 support

• Type: Bug
• Resolution: Unresolved
• Priority: Trivial
• Fix Version/s: Lustre 2.14.0
• Severity: 3
• Assignee: Alex Zhuravlev
• Reporter: Alex Zhuravlev

Description

gcc9 introduced new checks:

• address-of-packed-member
• missing-attributes
  it's easier to disable those for a while..

Comments

[Jian Yu]

It appears to be related to https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0b999ae3614d09d97a1575936bcee884f912b10e

So the -Werror=missing-attributes issue was fixed in kernel v5.0-rc7.

[Jian Yu]

Hit the same failures with gcc 9.4.0 on RHEL 8.6 with kernel 4.18.0-372.32.1.el8_6.

[Jian Yu]

I'm trying to build and install gcc 9.4.0 on RHEL 8.6 to see how the Lustre client build goes.

[Jian Yu]

Building the same codes with gcc 9.4.0 on Ubuntu 20.04.5 with kernel 5.4.0-135-generic passed.

[Jian Yu]

Building master branch with gcc 9.2.1 on RHEL 8.6 failed as follows:

# gcc --version | head -1
gcc (GCC) 9.2.1 20191120 (Red Hat 9.2.1-2)
# git clone git://git.whamcloud.com/fs/lustre-release.git
# cd lustre-release/
# sh autogen.sh
# ./configure --disable-server --with-linux=/usr/src/kernels/4.18.0-372.32.1.el8_6.x86_64
# make -j $(nproc)

/root/lustre-release/lnet/klnds/o2iblnd/o2iblnd.c: In function ‘kiblnd_unpack_rd’:
/root/lustre-release/lnet/klnds/o2iblnd/o2iblnd.c:147:13: error: taking address of packed member of ‘struct kib_rdma_desc’ may result in an unaligned pointer value [-Werror=address-of-packed-member]
  147 |   __swab32s(&rd->rd_key);
      |             ^~~~~~~~~~~
<~snip~>
/root/lustre-release/lnet/klnds/o2iblnd/o2iblnd.c: In function ‘kiblnd_unpack_msg’:
/root/lustre-release/lnet/klnds/o2iblnd/o2iblnd.c:264:13: error: taking address of packed member of ‘struct kib_msg’ may result in an unaligned pointer value [-Werror=address-of-packed-member]
  264 |   __swab64s(&msg->ibm_srcnid);
      |             ^~~~~~~~~~~~~~~~
<~snip~>
/root/lustre-release/lnet/klnds/o2iblnd/o2iblnd.c: At top level:
/usr/src/kernels/4.18.0-372.32.1.el8_6.x86_64/include/linux/module.h:129:6: error: ‘init_module’ specifies less restrictive attribute than its target ‘ko2iblnd_init’: ‘cold’ [-Werror=missing-attributes]
  129 |  int init_module(void) __attribute__((alias(#initfn)));
      |      ^~~~~~~~~~~
/root/lustre-release/lnet/klnds/o2iblnd/o2iblnd.c:3908:1: note: in expansion of macro ‘module_init’
 3908 | module_init(ko2iblnd_init);
      | ^~~~~~~~~~~
/root/lustre-release/lnet/klnds/o2iblnd/o2iblnd.c:3888:19: note: ‘init_module’ target declared here
 3888 | static int __init ko2iblnd_init(void)
      |                   ^~~~~~~~~~~~~
<~snip~>
                 from /root/lustre-release/lnet/klnds/o2iblnd/o2iblnd.c:38:
/usr/src/kernels/4.18.0-372.32.1.el8_6.x86_64/include/linux/module.h:135:7: error: ‘cleanup_module’ specifies less restrictive attribute than its target ‘ko2iblnd_exit’: ‘cold’ [-Werror=missing-attributes]
  135 |  void cleanup_module(void) __attribute__((alias(#exitfn)));
      |       ^~~~~~~~~~~~~~
/root/lustre-release/lnet/klnds/o2iblnd/o2iblnd.c:3909:1: note: in expansion of macro ‘module_exit’
 3909 | module_exit(ko2iblnd_exit);
      | ^~~~~~~~~~~
/root/lustre-release/lnet/klnds/o2iblnd/o2iblnd.c:3883:20: note: ‘cleanup_module’ target declared here
 3883 | static void __exit ko2iblnd_exit(void)
      |                    ^~~~~~~~~~~~~
<~snip~>

  CC [M]  /root/lustre-release/libcfs/libcfs/module.o
  CC [M]  /root/lustre-release/libcfs/libcfs/tracefile.o
In file included from /root/lustre-release/libcfs/libcfs/module.c:32:
include/linux/module.h:129:6: error: ‘init_module’ specifies less restrictive attribute than its target ‘libcfs_init’: ‘cold’ [-Werror=missing-attributes]
  129 |  int init_module(void) __attribute__((alias(#initfn)));
      |      ^~~~~~~~~~~
/root/lustre-release/libcfs/libcfs/module.c:962:1: note: in expansion of macro ‘module_init’
  962 | module_init(libcfs_init);
      | ^~~~~~~~~~~
/root/lustre-release/libcfs/libcfs/module.c:847:19: note: ‘init_module’ target declared here
  847 | static int __init libcfs_init(void)
      |                   ^~~~~~~~~~~
In file included from /root/lustre-release/libcfs/libcfs/module.c:32:
include/linux/module.h:135:7: error: ‘cleanup_module’ specifies less restrictive attribute than its target ‘libcfs_exit’: ‘cold’ [-Werror=missing-attributes]
  135 |  void cleanup_module(void) __attribute__((alias(#exitfn)));
      |       ^~~~~~~~~~~~~~
/root/lustre-release/libcfs/libcfs/module.c:963:1: note: in expansion of macro ‘module_exit’
  963 | module_exit(libcfs_exit);
      | ^~~~~~~~~~~
/root/lustre-release/libcfs/libcfs/module.c:918:20: note: ‘cleanup_module’ target declared here
  918 | static void __exit libcfs_exit(void)
      |                    ^~~~~~~~~~~
cc1: all warnings being treated as errors
make[6]: *** [scripts/Makefile.build:317: /root/lustre-release/libcfs/libcfs/module.o] Error 1

 

[James A Simmons]

We just ran into this issue with the lustre test module kinode.c. It appears to be related to https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0b999ae3614d09d97a1575936bcee884f912b10e

Also MOFED doesn't seem to build with gcc 9 as well

[James A Simmons]

Is it only ldiskfs? Also what ldiskfs series is being use on Fedora?

[Alex Zhuravlev]

here is example:

In file included from /home/alexey/head1/ldiskfs/super.c:20:
include/linux/module.h:132:6: error: ‘init_module’ specifies less restrictive attribute than its target ‘ldiskfs_init_fs’: ‘cold’ [-Werror=missing-attributes]
  132 |  int init_module(void) __attribute__((alias(#initfn)));
      |      ^~~~~~~~~~~
/home/alexey/head1/ldiskfs/super.c:6003:1: note: in expansion of macro ‘module_init’
 6003 | module_init(ldiskfs_init_fs)
      | ^~~~~~~~~~~
/home/alexey/head1/ldiskfs/super.c:5930:19: note: ‘init_module’ target declared here
 5930 | static int __init ldiskfs_init_fs(void)
      |                   ^~~~~~~~~~~~~~~
In file included from /home/alexey/head1/ldiskfs/super.c:20:

[James A Simmons]

I wonder what the default flags are for fedora. I'm using 

gcc version 9.3.0 (Ubuntu 9.3.0-10ubuntu2)

What are the build failures you are still seeing?

[Alex Zhuravlev]

well, I still can't build master with gcc9