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authorMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>2013-09-25 17:16:16 +0400
committerArnaldo Carvalho de Melo <acme@redhat.com>2013-09-25 19:27:31 +0400
commit576b523721b7fbbf44a411ff0b3d958906c41653 (patch)
treef746182bb02046b9af844d2944c9af4302d2db76 /tools/perf/util/probe-finder.h
parent384c671e33a7ddf905f2c60b433b9883f0e5a605 (diff)
downloadlinux-576b523721b7fbbf44a411ff0b3d958906c41653.tar.xz
perf probe: Fix probing symbols with optimization suffix
Fix perf probe to probe on some symbols which have some optimzation suffixes, e.g. ".part", ".isra", and ".constprop". To fix this issue, instead of using the DIE name, perf probe uses the symbol name found by dwfl_module_addrsym(). This also involves a perf probe --vars operation update which now shows the symbol name instead of the DIE name. Without this patch, putting a probe on an inlined function which was compiled with a suffixed symbol will fail like this: $ perf probe -v getname_flags probe-definition(0): getname_flags symbol:getname_flags file:(null) line:0 offset:0 return:0 lazy:(null) 0 arguments Looking at the vmlinux_path (6 entries long) Using /lib/modules/3.11.0+/build/vmlinux for symbols found inline addr: 0xffffffff8119bb70 Probe point found: getname_flags+0 found inline addr: 0xffffffff8119bcb6 Probe point found: getname+6 found inline addr: 0xffffffff811a06a6 Probe point found: user_path_at_empty+6 find 3 probe_trace_events. Opening /sys/kernel/debug//tracing/kprobe_events write=1 Added new events: Writing event: p:probe/getname_flags getname_flags+0 Failed to write event: No such file or directory Error: Failed to add events. (-1) Because the debuginfo knows only the original (non suffix) symbol name, it uses the original symbol for probe address but the kernel (kallsyms) knows only suffixed symbol. Then, the kernel rejects that original symbol. This patch uses dwfl_module_addrsym() to get the correct (suffixed) symbol from symtab when a probe point is found. Reported-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20130925131616.31632.46658.stgit@udc4-manage.rcp.hitachi.co.jp Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/probe-finder.h')
-rw-r--r--tools/perf/util/probe-finder.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index 17e94d0c36f9..3b7d63018960 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -23,6 +23,7 @@ static inline int is_c_varname(const char *name)
/* debug information structure */
struct debuginfo {
Dwarf *dbg;
+ Dwfl_Module *mod;
Dwfl *dwfl;
Dwarf_Addr bias;
};
@@ -77,6 +78,7 @@ struct probe_finder {
struct trace_event_finder {
struct probe_finder pf;
+ Dwfl_Module *mod; /* For solving symbols */
struct probe_trace_event *tevs; /* Found trace events */
int ntevs; /* Number of trace events */
int max_tevs; /* Max number of trace events */
@@ -84,6 +86,7 @@ struct trace_event_finder {
struct available_var_finder {
struct probe_finder pf;
+ Dwfl_Module *mod; /* For solving symbols */
struct variable_list *vls; /* Found variable lists */
int nvls; /* Number of variable lists */
int max_vls; /* Max no. of variable lists */