diff options
author | Kumar Kartikeya Dwivedi <memxor@gmail.com> | 2021-10-09 09:39:00 +0530 |
---|---|---|
committer | Andrii Nakryiko <andrii@kernel.org> | 2021-10-19 16:55:50 -0700 |
commit | 588cd7ef5382eb89d09a64ee9ba85e4f9a5b0bcb (patch) | |
tree | bb91099b7f7e6196525896fa9b4e06ee64466e66 /tools/lib | |
parent | 32fa0efab63eb724b4c439117d94be8b77c0bc3c (diff) | |
download | linux-588cd7ef5382eb89d09a64ee9ba85e4f9a5b0bcb.tar.bz2 |
bpf: Silence Coverity warning for find_kfunc_desc_btf
The helper function returns a pointer that in the failure case encodes
an error in the struct btf pointer. The current code lead to Coverity
warning about the use of the invalid pointer:
*** CID 1507963: Memory - illegal accesses (USE_AFTER_FREE)
/kernel/bpf/verifier.c: 1788 in find_kfunc_desc_btf()
1782 return ERR_PTR(-EINVAL);
1783 }
1784
1785 kfunc_btf = __find_kfunc_desc_btf(env, offset, btf_modp);
1786 if (IS_ERR_OR_NULL(kfunc_btf)) {
1787 verbose(env, "cannot find module BTF for func_id %u\n", func_id);
>>> CID 1507963: Memory - illegal accesses (USE_AFTER_FREE)
>>> Using freed pointer "kfunc_btf".
1788 return kfunc_btf ?: ERR_PTR(-ENOENT);
1789 }
1790 return kfunc_btf;
1791 }
1792 return btf_vmlinux ?: ERR_PTR(-ENOENT);
1793 }
Daniel suggested the use of ERR_CAST so that the intended use is clear
to Coverity, but on closer look it seems that we never return NULL from
the helper. Andrii noted that since __find_kfunc_desc_btf already logs
errors for all cases except btf_get_by_fd, it is much easier to add
logging for that and remove the IS_ERR check altogether, returning
directly from it.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211009040900.803436-1-memxor@gmail.com
Diffstat (limited to 'tools/lib')
0 files changed, 0 insertions, 0 deletions