5.10-stable review patch. If anyone has any objections, please let me know.
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From: Arnaldo Carvalho de Melo acme@redhat.com
[ Upstream commit 979e9c9fc9c2a761303585e07fe2699bdd88182f ]
In 616b14b47a86d880 ("perf build: Conditionally define NDEBUG") we started using NDEBUG=1 when DEBUG=1 isn't present, so code that is enclosed with assert() is not called.
In dd317df072071903 ("perf build: Make binutil libraries opt in") we stopped linking against binutils-devel, for licensing reasons.
Recently people asked me why annotation of BPF programs wasn't working, i.e. this:
$ perf annotate bpf_prog_5280546344e3f45c_kfree_skb
was returning:
case SYMBOL_ANNOTATE_ERRNO__NO_LIBOPCODES_FOR_BPF: scnprintf(buf, buflen, "Please link with binutils's libopcode to enable BPF annotation");
This was on a fedora rpm, so its new enough that I had to try to test by rebuilding using BUILD_NONDISTRO=1, only to get it segfaulting on me.
This combination made this libopcode function not to be called:
assert(bfd_check_format(bfdf, bfd_object));
Changing it to:
if (!bfd_check_format(bfdf, bfd_object)) abort();
Made it work, looking at this "check" function made me realize it changes the 'bfdf' internal state, i.e. we better call it.
So stop using assert() on it, just call it and abort if it fails.
Probably it is better to propagate the error, etc, but it seems it is unlikely to fail from the usage done so far and we really need to stop using libopcodes, so do the quick fix above and move on.
With it we have BPF annotation back working when built with BUILD_NONDISTRO=1:
⬢[acme@toolbox perf-tools-next]$ perf annotate --stdio2 bpf_prog_5280546344e3f45c_kfree_skb | head No kallsyms or vmlinux with build-id 939bc71a1a51cdc434e60af93c7e734f7d5c0e7e was found Samples: 12 of event 'cpu-clock:ppp', 4000 Hz, Event count (approx.): 3000000, [percent: local period] bpf_prog_5280546344e3f45c_kfree_skb() bpf_prog_5280546344e3f45c_kfree_skb Percent int kfree_skb(struct trace_event_raw_kfree_skb *args) { nop 33.33 xchg %ax,%ax push %rbp mov %rsp,%rbp sub $0x180,%rsp push %rbx push %r13 ⬢[acme@toolbox perf-tools-next]$
Fixes: 6987561c9e86eace ("perf annotate: Enable annotation of BPF programs") Cc: Adrian Hunter adrian.hunter@intel.com Cc: Ian Rogers irogers@google.com Cc: Jiri Olsa jolsa@kernel.org Cc: Mohamed Mahmoud mmahmoud@redhat.com Cc: Namhyung Kim namhyung@kernel.org Cc: Dave Tucker datucker@redhat.com Cc: Derek Barbosa debarbos@redhat.com Cc: Song Liu songliubraving@fb.com Link: https://lore.kernel.org/lkml/ZMrMzoQBe0yqMek1@kernel.org Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/annotate.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c index 3081894547883..c9078cee6be01 100644 --- a/tools/perf/util/annotate.c +++ b/tools/perf/util/annotate.c @@ -1718,8 +1718,11 @@ static int symbol__disassemble_bpf(struct symbol *sym, perf_exe(tpath, sizeof(tpath));
bfdf = bfd_openr(tpath, NULL); - assert(bfdf); - assert(bfd_check_format(bfdf, bfd_object)); + if (bfdf == NULL) + abort(); + + if (!bfd_check_format(bfdf, bfd_object)) + abort();
s = open_memstream(&buf, &buf_size); if (!s) { @@ -1767,7 +1770,8 @@ static int symbol__disassemble_bpf(struct symbol *sym, #else disassemble = disassembler(bfdf); #endif - assert(disassemble); + if (disassemble == NULL) + abort();
fflush(s); do {