Em Tue, Feb 23, 2021 at 06:02:58PM +0300, Evgenii Shatokhin escreveu: > On 23.02.2021 10:37, Masami Hiramatsu wrote: > > The kernel modules have .text.* subsections such as .text.unlikely. > > Since dso__process_kernel_symbol() only identify the symbols in the ".text" > > section as the text symbols and inserts it in the default dso in the map, > > the symbols in such subsections can not be found by map__find_symbol(). > > > > This adds the symbols in those subsections to the default dso in the map so > > that map__find_symbol() can find them. This solves the perf-probe issue on > > probing online module. > > > > Without this fix, probing on a symbol in .text.unlikely fails. > > ---- > > # perf probe -m nf_conntrack nf_l4proto_log_invalid > > Probe point 'nf_l4proto_log_invalid' not found. > > Error: Failed to add events. > > ---- > > > > With this fix, it works because map__find_symbol() can find the symbol > > correctly. > > ---- > > # perf probe -m nf_conntrack nf_l4proto_log_invalid > > Added new event: > > probe:nf_l4proto_log_invalid (on nf_l4proto_log_invalid in > > nf_conntrack) > > > > You can now use it in all perf tools, such as: > > > > perf record -e probe:nf_l4proto_log_invalid -aR sleep 1 > > > > ---- > > > > Reported-by: Evgenii Shatokhin <[email protected]> > > Signed-off-by: Masami Hiramatsu <[email protected]> > > Thanks for the fix! > > It looks like it helps, at least with nf_conntrack in kernel 5.11:
So I'm taking this as you providing a: Tested-by: Evgenii Shatokhin <[email protected]> ok? - Arnaldo > --------------------- > # ./perf probe -v -m nf_conntrack nf_ct_resolve_clash > probe-definition(0): nf_ct_resolve_clash > symbol:nf_ct_resolve_clash file:(null) line:0 offset:0 return:0 lazy:(null) > 0 arguments > Failed to get build-id from nf_conntrack. > Cache open error: -1 > Open Debuginfo file: > /lib/modules/5.11.0-test01/kernel/net/netfilter/nf_conntrack.ko > Try to find probe point from debuginfo. > Matched function: nf_ct_resolve_clash [33616] > Probe point found: nf_ct_resolve_clash+0 > Found 1 probe_trace_events. > Opening /sys/kernel/tracing//kprobe_events write=1 > Opening /sys/kernel/tracing//README write=0 > Writing event: p:probe/nf_ct_resolve_clash > nf_conntrack:nf_ct_resolve_clash+0 > Added new event: > probe:nf_ct_resolve_clash (on nf_ct_resolve_clash in nf_conntrack) > > You can now use it in all perf tools, such as: > > perf record -e probe:nf_ct_resolve_clash -aR sleep 1 > --------------------- > > I guess, the patch is suitable for stable kernel branches as well. > > Without the patch, the workaround you suggested earlier (using the full path > to nf_conntrack.ko) works too. > > > --- > > tools/perf/util/symbol-elf.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c > > index 6dff843fd883..0c1113236913 100644 > > --- a/tools/perf/util/symbol-elf.c > > +++ b/tools/perf/util/symbol-elf.c > > @@ -985,7 +985,9 @@ static int dso__process_kernel_symbol(struct dso *dso, > > struct map *map, > > if (strcmp(section_name, (curr_dso->short_name + dso->short_name_len)) > > == 0) > > return 0; > > - if (strcmp(section_name, ".text") == 0) { > > + /* .text and .text.* are included in the text dso */ > > + if (strncmp(section_name, ".text", 5) == 0 && > > + (section_name[5] == '\0' || section_name[5] == '.')) { > > /* > > * The initial kernel mapping is based on > > * kallsyms and identity maps. Overwrite it to > > > > . > > > > Regards, > Evgenii -- - Arnaldo
