From 05670f81d1287c40ec861186e4c4e3401013e7fb Mon Sep 17 00:00:00 2001 From: Matthieu Baerts Date: Wed, 1 Nov 2023 19:16:01 +0100 Subject: [PATCH] bpf: fix compilation error without CGROUPS 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 Closes: https://lore.kernel.org/oe-kbuild-all/202310260528.aHWgVFqq-lkp@intel.com/ Signed-off-by: Matthieu Baerts [ added missing ifdefs for BTF_ID cgroup definitions ] Signed-off-by: Jiri Olsa Link: https://lore.kernel.org/r/20231101181601.1493271-1-jolsa@kernel.org Signed-off-by: Alexei Starovoitov --- kernel/bpf/helpers.c | 8 +++++--- kernel/bpf/task_iter.c | 4 ++++ kernel/bpf/verifier.c | 8 ++++++++ 3 files changed, 17 insertions(+), 3 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index e46ac288a1080..95449ea7cc1b3 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2564,15 +2564,17 @@ BTF_ID_FLAGS(func, bpf_iter_num_destroy, KF_ITER_DESTROY) BTF_ID_FLAGS(func, bpf_iter_task_vma_new, KF_ITER_NEW | KF_RCU) BTF_ID_FLAGS(func, bpf_iter_task_vma_next, KF_ITER_NEXT | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_task_vma_destroy, KF_ITER_DESTROY) +#ifdef CONFIG_CGROUPS BTF_ID_FLAGS(func, bpf_iter_css_task_new, KF_ITER_NEW | KF_TRUSTED_ARGS) BTF_ID_FLAGS(func, bpf_iter_css_task_next, KF_ITER_NEXT | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_css_task_destroy, KF_ITER_DESTROY) -BTF_ID_FLAGS(func, bpf_iter_task_new, KF_ITER_NEW | KF_TRUSTED_ARGS | KF_RCU_PROTECTED) -BTF_ID_FLAGS(func, bpf_iter_task_next, KF_ITER_NEXT | KF_RET_NULL) -BTF_ID_FLAGS(func, bpf_iter_task_destroy, KF_ITER_DESTROY) BTF_ID_FLAGS(func, bpf_iter_css_new, KF_ITER_NEW | KF_TRUSTED_ARGS | KF_RCU_PROTECTED) BTF_ID_FLAGS(func, bpf_iter_css_next, KF_ITER_NEXT | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_css_destroy, KF_ITER_DESTROY) +#endif +BTF_ID_FLAGS(func, bpf_iter_task_new, KF_ITER_NEW | KF_TRUSTED_ARGS | KF_RCU_PROTECTED) +BTF_ID_FLAGS(func, bpf_iter_task_next, KF_ITER_NEXT | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_iter_task_destroy, KF_ITER_DESTROY) BTF_ID_FLAGS(func, bpf_dynptr_adjust) BTF_ID_FLAGS(func, bpf_dynptr_is_null) BTF_ID_FLAGS(func, bpf_dynptr_is_rdonly) diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c index 654601dd6b493..8967d1ac75517 100644 --- a/kernel/bpf/task_iter.c +++ b/kernel/bpf/task_iter.c @@ -892,6 +892,8 @@ __bpf_kfunc void bpf_iter_task_vma_destroy(struct bpf_iter_task_vma *it) __diag_pop(); +#ifdef CONFIG_CGROUPS + struct bpf_iter_css_task { __u64 __opaque[1]; } __attribute__((aligned(8))); @@ -950,6 +952,8 @@ __bpf_kfunc void bpf_iter_css_task_destroy(struct bpf_iter_css_task *it) __diag_pop(); +#endif /* CONFIG_CGROUPS */ + struct bpf_iter_task { __u64 __opaque[3]; } __attribute__((aligned(8))); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 857d766945171..8c91e0e54e27b 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5388,7 +5388,9 @@ static bool in_rcu_cs(struct bpf_verifier_env *env) /* Once GCC supports btf_type_tag the following mechanism will be replaced with tag check */ BTF_SET_START(rcu_protected_types) BTF_ID(struct, prog_test_ref_kfunc) +#ifdef CONFIG_CGROUPS BTF_ID(struct, cgroup) +#endif BTF_ID(struct, bpf_cpumask) BTF_ID(struct, task_struct) BTF_SET_END(rcu_protected_types) @@ -10835,7 +10837,9 @@ BTF_ID(func, bpf_dynptr_clone) BTF_ID(func, bpf_percpu_obj_new_impl) BTF_ID(func, bpf_percpu_obj_drop_impl) BTF_ID(func, bpf_throw) +#ifdef CONFIG_CGROUPS BTF_ID(func, bpf_iter_css_task_new) +#endif BTF_SET_END(special_kfunc_set) BTF_ID_LIST(special_kfunc_list) @@ -10861,7 +10865,11 @@ BTF_ID(func, bpf_dynptr_clone) BTF_ID(func, bpf_percpu_obj_new_impl) BTF_ID(func, bpf_percpu_obj_drop_impl) BTF_ID(func, bpf_throw) +#ifdef CONFIG_CGROUPS BTF_ID(func, bpf_iter_css_task_new) +#else +BTF_ID_UNUSED +#endif static bool is_kfunc_ret_null(struct bpf_kfunc_call_arg_meta *meta) { -- 2.30.2