Re: [PATCH 6.1 00/86] 6.1.104-rc2 review

[Salvatore Bonaccorso <carnil@debian.org>]

Hi Greg,

[adding as well people involved in the original commit and the
backporting for 6.1.y branch]

On Thu, Aug 08, 2024 at 12:33:22PM +0200, Salvatore Bonaccorso wrote:
> Hi Greg,
> 
> On Thu, Aug 08, 2024 at 11:11:49AM +0200, Greg Kroah-Hartman wrote:
> > This is the start of the stable review cycle for the 6.1.104 release.
> > There are 86 patches in this series, all will be posted as a response
> > to this one.  If anyone has any issues with these being applied, please
> > let me know.
> > 
> > Responses should be made by Sat, 10 Aug 2024 09:11:02 +0000.
> > Anything received after that time might be too late.
> 
> Sorry for bothering you again with it (see previous comment on
> 6.1.103, respectively 6.1.104-rc1): bpftool still would fail to
> compile:
> 
> gcc -O2 -W -Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wbad-function-cast -Wdeclaration-after-statement -Wformat-security -Wformat-y2k -Winit-self -Wmissing-declarations -Wmissing-prototypes -Wno-system-headers -Wold-style-definition -Wpacked -Wredundant-decls -Wstrict-prototypes -Wswitch-default -Wundef -Wwrite-strings -Wformat -Wno-type-limits -Wstrict-aliasing=3 -Wshadow -DPACKAGE='"bpftool"' -D__EXPORTED_HEADERS__ -I. -I/home/build/linux-stable-rc/tools/bpf/bpftool/libbpf/include -I/home/build/linux-stable-rc/kernel/bpf/ -I/home/build/linux-stable-rc/tools/include -I/home/build/linux-stable-rc/tools/include/uapi -DUSE_LIBCAP -DBPFTOOL_WITHOUT_SKELETONS -c -MMD prog.c -o prog.o
> prog.c: In function ‘load_with_options’:
> prog.c:1710:23: warning: implicit declaration of function ‘create_and_mount_bpffs_dir’ [-Wimplicit-function-declaration]
>  1710 |                 err = create_and_mount_bpffs_dir(pinmaps);
>       |                       ^~~~~~~~~~~~~~~~~~~~~~~~~~
> gcc -O2 -W -Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wbad-function-cast -Wdeclaration-after-statement -Wformat-security -Wformat-y2k -Winit-self -Wmissing-declarations -Wmissing-prototypes -Wno-system-headers -Wold-style-definition -Wpacked -Wredundant-decls -Wstrict-prototypes -Wswitch-default -Wundef -Wwrite-strings -Wformat -Wno-type-limits -Wstrict-aliasing=3 -Wshadow -DPACKAGE='"bpftool"' -D__EXPORTED_HEADERS__ -I. -I/home/build/linux-stable-rc/tools/bpf/bpftool/libbpf/include -I/home/build/linux-stable-rc/kernel/bpf/ -I/home/build/linux-stable-rc/tools/include -I/home/build/linux-stable-rc/tools/include/uapi -DUSE_LIBCAP -DBPFTOOL_WITHOUT_SKELETONS  btf.o btf_dumper.o cfg.o cgroup.o common.o feature.o gen.o iter.o json_writer.o link.o main.o map.o map_perf_ring.o net.o netlink_dumper.o perf.o pids.o prog.o struct_ops.o tracelog.o xlated_dumper.o disasm.o /home/build/linux-stable-rc/tools/bpf/bpftool/libbpf/libbpf.a -lelf -lz -lcap -o bpftool
> /bin/ld: prog.o: in function `load_with_options':
> prog.c:(.text+0x2f98): undefined reference to `create_and_mount_bpffs_dir'
> /bin/ld: prog.c:(.text+0x2ff2): undefined reference to `create_and_mount_bpffs_dir'
> collect2: error: ld returned 1 exit status
> make[1]: *** [Makefile:216: bpftool] Error 1
> make: *** [Makefile:113: bpftool] Error 2
> 
> Reverting 65dd9cbafec2f6f7908cebcab0386f750fc352af fixes the issue. In
> fact 65dd9cbafec2f6f7908cebcab0386f750fc352af is the only commit
> adding call to create_and_mount_bpffs_dir:
> 
> $ git grep create_and_mount_bpffs_dir
> tools/bpf/bpftool/prog.c:               err = create_and_mount_bpffs_dir(pinmaps);

Just one additional note, at least 478a535ae54a ("bpftool: Mount bpffs
on provided dir instead of parent dir") would be a reqisite where the
code was refactored introducing create_and_mount_bpffs_dir() (but
won't apply cleanly to 6.1.y). But are more requisites needed?

Should it be safest to just revert the breaking commit for the bpftool
build?

Regards,
Salvatore