Messages in this thread | | | Date | Wed, 1 Nov 2023 09:25:34 +0100 | Subject | Re: [PATCH bpf-next] bpf: fix compilation error without CGROUPS | From | Matthieu Baerts <> |
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Hi Jirka, Alexei,
On 01/11/2023 08:25, Jiri Olsa wrote: > On Tue, Oct 31, 2023 at 08:54:56PM -0700, Alexei Starovoitov wrote: >> On Tue, Oct 31, 2023 at 10:05 AM Jiri Olsa <olsajiri@gmail.com> wrote: >>> >>> On Tue, Oct 31, 2023 at 04:49:34PM +0100, Matthieu Baerts wrote: >>>> Our MPTCP CI complained [1] -- and KBuild too -- that it was no longer >>>> possible to build the kernel without CONFIG_CGROUPS: >>>> >>>> kernel/bpf/task_iter.c: In function 'bpf_iter_css_task_new': >>>> kernel/bpf/task_iter.c:919:14: error: 'CSS_TASK_ITER_PROCS' undeclared (first use in this function) >>>> 919 | case CSS_TASK_ITER_PROCS | CSS_TASK_ITER_THREADED: >>>> | ^~~~~~~~~~~~~~~~~~~ >>>> kernel/bpf/task_iter.c:919:14: note: each undeclared identifier is reported only once for each function it appears in >>>> kernel/bpf/task_iter.c:919:36: error: 'CSS_TASK_ITER_THREADED' undeclared (first use in this function) >>>> 919 | case CSS_TASK_ITER_PROCS | CSS_TASK_ITER_THREADED: >>>> | ^~~~~~~~~~~~~~~~~~~~~~ >>>> kernel/bpf/task_iter.c:927:60: error: invalid application of 'sizeof' to incomplete type 'struct css_task_iter' >>>> 927 | kit->css_it = bpf_mem_alloc(&bpf_global_ma, sizeof(struct css_task_iter)); >>>> | ^~~~~~ >>>> kernel/bpf/task_iter.c:930:9: error: implicit declaration of function 'css_task_iter_start'; did you mean 'task_seq_start'? [-Werror=implicit-function-declaration] >>>> 930 | css_task_iter_start(css, flags, kit->css_it); >>>> | ^~~~~~~~~~~~~~~~~~~ >>>> | task_seq_start >>>> kernel/bpf/task_iter.c: In function 'bpf_iter_css_task_next': >>>> kernel/bpf/task_iter.c:940:16: error: implicit declaration of function 'css_task_iter_next'; did you mean 'class_dev_iter_next'? [-Werror=implicit-function-declaration] >>>> 940 | return css_task_iter_next(kit->css_it); >>>> | ^~~~~~~~~~~~~~~~~~ >>>> | class_dev_iter_next >>>> kernel/bpf/task_iter.c:940:16: error: returning 'int' from a function with return type 'struct task_struct *' makes pointer from integer without a cast [-Werror=int-conversion] >>>> 940 | return css_task_iter_next(kit->css_it); >>>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >>>> kernel/bpf/task_iter.c: In function 'bpf_iter_css_task_destroy': >>>> kernel/bpf/task_iter.c:949:9: error: implicit declaration of function 'css_task_iter_end' [-Werror=implicit-function-declaration] >>>> 949 | css_task_iter_end(kit->css_it); >>>> | ^~~~~~~~~~~~~~~~~ >>>> >>>> This patch simply surrounds with a #ifdef the new code requiring CGroups >>>> support. It seems enough for the compiler and this is similar to >>>> bpf_iter_css_{new,next,destroy}() functions where no other #ifdef have >>>> been added in kernel/bpf/helpers.c and in the selftests. >>>> >>>> Fixes: 9c66dc94b62a ("bpf: Introduce css_task open-coded iterator kfuncs") >>>> Link: https://github.com/multipath-tcp/mptcp_net-next/actions/runs/6665206927 >>>> Reported-by: kernel test robot <lkp@intel.com> >>>> Closes: https://lore.kernel.org/oe-kbuild-all/202310260528.aHWgVFqq-lkp@intel.com/ >>>> Signed-off-by: Matthieu Baerts <matttbe@kernel.org> >>> >>> Acked/Tested-by: Jiri Olsa <jolsa@kernel.org> >> >> I believe this patch has the same issue as Arnd's patch: >> https://lore.kernel.org/all/CAADnVQL-zoFPPOVu3nM981gKxRu7Q3G3LTRsKstJEeahpoR1RQ@mail.gmail.com/
@Alexei: Arf, sorry, I didn't find this patch when searching for "9c66dc94b62a" on lore. I don't know why I didn't search for the commit title as usual...
>> I'd like to merge the fix asap. Please make it a complete fix. > > ugh, it won't fail the build, it just warns.. I think we should > fail the build in that case, I'll check
@Jirka: Thank you for checking that! Please tell me if you want me to send a v2 or if you prefer to do that. I don't mind if you prefer to send your own patches, as long as there is a fix for that at the end :)
Note that if a warning is emitted for these new bpf_iter_css_task_*() functions, I guess you will have the same issue with bpf_iter_css_*() and probably others as mentioned in my commit message.
Cheers, Matt
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