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bpf: Fix a BTF_ID_LIST bug with CONFIG_DEBUG_INFO_BTF not set 

With CONFIG_DEBUG_INFO_BTF not set, we hit the following compilation error,
  /.../kernel/bpf/verifier.c:8196:23: error: array index 6 is past the end of the array
  (that has type 'u32[5]' (aka 'unsigned int[5]')) [-Werror,-Warray-bounds]
        if (meta->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx])
                             ^                  ~~~~~~~~~~~~~~~~~~~~~~~
  /.../kernel/bpf/verifier.c:8174:1: note: array 'special_kfunc_list' declared here
  BTF_ID_LIST(special_kfunc_list)
  ^
  /.../include/linux/btf_ids.h:207:27: note: expanded from macro 'BTF_ID_LIST'
  #define BTF_ID_LIST(name) static u32 __maybe_unused name[5];
                            ^
  /.../kernel/bpf/verifier.c:8443:19: error: array index 5 is past the end of the array
  (that has type 'u32[5]' (aka 'unsigned int[5]')) [-Werror,-Warray-bounds]
                 btf_id == special_kfunc_list[KF_bpf_list_pop_back];
                           ^                  ~~~~~~~~~~~~~~~~~~~~
  /.../kernel/bpf/verifier.c:8174:1: note: array 'special_kfunc_list' declared here
  BTF_ID_LIST(special_kfunc_list)
  ^
  /.../include/linux/btf_ids.h:207:27: note: expanded from macro 'BTF_ID_LIST'
  #define BTF_ID_LIST(name) static u32 __maybe_unused name[5];
  ...

Fix the problem by increase the size of BTF_ID_LIST to 16 to avoid compilation error
and also prevent potentially unintended issue due to out-of-bound access.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221123155759.2669749-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Yonghong Song 2022-11-23 07:57:59 -08:00 committed by Alexei Starovoitov
parent 8ac88eece8
commit beb3d47d1d
1 changed files with 1 additions and 1 deletions
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2
include/linux/btf_ids.h
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@ -204,7 +204,7 @@ extern struct btf_id_set8 name;
#else
#define BTF_ID_LIST(name) static u32 __maybe_unused name[5];
#define BTF_ID_LIST(name) static u32 __maybe_unused name[16];
#define BTF_ID(prefix, name)
#define BTF_ID_FLAGS(prefix, name, ...)
#define BTF_ID_UNUSED