Messages in this thread | | | Date | Mon, 28 Dec 2020 18:09:25 -0500 | From | Sasha Levin <> | Subject | Re: [PATCH 5.4 106/453] libbpf: Fix BTF data layout checks and allow empty BTF |
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On Mon, Dec 28, 2020 at 11:47:44AM -0800, Andrii Nakryiko wrote: >On Mon, Dec 28, 2020 at 7:49 AM Naresh Kamboju ><naresh.kamboju@linaro.org> wrote: >> >> Perf build failed on stable-rc 5.4 branch due to this patch. >> >> On Mon, 28 Dec 2020 at 19:15, Greg Kroah-Hartman >> <gregkh@linuxfoundation.org> wrote: >> > >> > From: Andrii Nakryiko <andrii@kernel.org> >> > >> > [ Upstream commit d8123624506cd62730c9cd9c7672c698e462703d ] >> > >> > Make data section layout checks stricter, disallowing overlap of types and >> > strings data. >> > >> > Additionally, allow BTFs with no type data. There is nothing inherently wrong >> > with having BTF with no types (put potentially with some strings). This could >> > be a situation with kernel module BTFs, if module doesn't introduce any new >> > type information. >> > >> > Also fix invalid offset alignment check for btf->hdr->type_off. >> > >> > Fixes: 8a138aed4a80 ("bpf: btf: Add BTF support to libbpf") >> > Signed-off-by: Andrii Nakryiko <andrii@kernel.org> >> > Signed-off-by: Alexei Starovoitov <ast@kernel.org> >> > Link: https://lore.kernel.org/bpf/20201105043402.2530976-8-andrii@kernel.org >> > Signed-off-by: Sasha Levin <sashal@kernel.org> >> > --- >> > tools/lib/bpf/btf.c | 16 ++++++---------- >> > 1 file changed, 6 insertions(+), 10 deletions(-) >> > >> > diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c >> > index d606a358480da..3380aadb74655 100644 >> > --- a/tools/lib/bpf/btf.c >> > +++ b/tools/lib/bpf/btf.c >> > @@ -100,22 +100,18 @@ static int btf_parse_hdr(struct btf *btf) >> > return -EINVAL; >> > } >> > >> > - if (meta_left < hdr->type_off) { >> > - pr_debug("Invalid BTF type section offset:%u\n", hdr->type_off); >> > + if (meta_left < hdr->str_off + hdr->str_len) { >> > + pr_debug("Invalid BTF total size:%u\n", btf->raw_size); >> >> In file included from btf.c:17:0: >> btf.c: In function 'btf_parse_hdr': >> btf.c:104:48: error: 'struct btf' has no member named 'raw_size'; did >> you mean 'data_size'? >> pr_debug("Invalid BTF total size:%u\n", btf->raw_size); >> ^ >> libbpf_internal.h:59:40: note: in definition of macro '__pr' >> libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \ >> ^~~~~~~~~~~ >> btf.c:104:3: note: in expansion of macro 'pr_debug' >> pr_debug("Invalid BTF total size:%u\n", btf->raw_size); >> ^~~~~~~~ >> > >This patch fixes the bug introduced back in 8a138aed4a80 ("bpf: btf: >Add BTF support to libbpf"), but a bunch of other refactorings >happened since then, adding/renaming struct btf internals. The fix >here is not that critical, so it's probably best to just drop this >patch from the stable, if possible. Would it be ok, Greg?
I'll drop it, thanks.
-- Thanks, Sasha
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