3.16.82-rc1 review patch. If anyone has any objections, please let me know.
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From: Masami Hiramatsu mhiramat@kernel.org
commit 5d16dbcc311d91267ddb45c6da4f187be320ecee upstream.
Fix 'perf probe' to probe a function which has no entry pc or low pc but only has ranges attribute.
probe_point_search_cb() uses dwarf_entrypc() to get the probe address, but that doesn't work for the function DIE which has only ranges attribute. Use die_entrypc() instead.
Without this fix:
# perf probe -k ../build-x86_64/vmlinux -D clear_tasks_mm_cpumask:0 Probe point 'clear_tasks_mm_cpumask' not found. Error: Failed to add events.
With this:
# perf probe -k ../build-x86_64/vmlinux -D clear_tasks_mm_cpumask:0 p:probe/clear_tasks_mm_cpumask clear_tasks_mm_cpumask+0
Committer testing:
Before:
[root@quaco ~]# perf probe clear_tasks_mm_cpumask:0 Probe point 'clear_tasks_mm_cpumask' not found. Error: Failed to add events. [root@quaco ~]#
After:
[root@quaco ~]# perf probe clear_tasks_mm_cpumask:0 Added new event: probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask)
You can now use it in all perf tools, such as:
perf record -e probe:clear_tasks_mm_cpumask -aR sleep 1
[root@quaco ~]#
Using it with 'perf trace':
[root@quaco ~]# perf trace -e probe:clear_tasks_mm_cpumask
Doesn't seem to be used in x86_64:
$ find . -name "*.c" | xargs grep clear_tasks_mm_cpumask ./kernel/cpu.c: * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU ./kernel/cpu.c:void clear_tasks_mm_cpumask(int cpu) ./arch/xtensa/kernel/smp.c: clear_tasks_mm_cpumask(cpu); ./arch/csky/kernel/smp.c: clear_tasks_mm_cpumask(cpu); ./arch/sh/kernel/smp.c: clear_tasks_mm_cpumask(cpu); ./arch/arm/kernel/smp.c: clear_tasks_mm_cpumask(cpu); ./arch/powerpc/mm/nohash/mmu_context.c: clear_tasks_mm_cpumask(cpu); $ find . -name "*.h" | xargs grep clear_tasks_mm_cpumask ./include/linux/cpu.h:void clear_tasks_mm_cpumask(int cpu); $ find . -name "*.S" | xargs grep clear_tasks_mm_cpumask $
Fixes: e1ecbbc3fa83 ("perf probe: Fix to handle optimized not-inlined functions") Reported-by: Arnaldo Carvalho de Melo acme@kernel.org Tested-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Masami Hiramatsu mhiramat@kernel.org Cc: Jiri Olsa jolsa@redhat.com Cc: Namhyung Kim namhyung@kernel.org Link: http://lore.kernel.org/lkml/157199319438.8075.4695576954550638618.stgit@devn... Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Ben Hutchings ben@decadent.org.uk --- tools/perf/util/probe-finder.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/tools/perf/util/probe-finder.c +++ b/tools/perf/util/probe-finder.c @@ -908,7 +908,7 @@ static int probe_point_search_cb(Dwarf_D param->retval = find_probe_point_by_line(pf); } else if (die_is_func_instance(sp_die)) { /* Instances always have the entry address */ - dwarf_entrypc(sp_die, &pf->addr); + die_entrypc(sp_die, &pf->addr); /* But in some case the entry address is 0 */ if (pf->addr == 0) { pr_debug("%s has no entry PC. Skipped\n",