diff options
authorHe Kuang <>2015-04-25 16:08:58 +0800
committerArnaldo Carvalho de Melo <>2015-04-27 13:57:29 -0300
commitd13855ef18e1852b2c4dc86ddf5759c5b34628cb (patch)
parentc671835021798c1c40ca0b55b49feff76ed5e0e1 (diff)
perf probe: Fix bug with global variables handling
There are missing curly braces which causes find_variable() return wrong value when probing with global variables. This problem can be reproduced as following: $ perf probe -v --add='generic_perform_write global_variable_for_test' ... Try to find probe point from debuginfo. Probe point found: generic_perform_write+0 Searching 'global_variable_for_test' variable in context. An error occurred in debuginfo analysis (-2). Error: Failed to add events. Reason: No such file or directory (Code: -2) After this patch: $ perf probe -v --add='generic_perform_write global_variable_for_test' ... Converting variable global_variable_for_test into trace event. global_variable_for_test type is int. Found 1 probe_trace_events. Opening /sys/kernel/debug/tracing/kprobe_events write=1 Added new event: Writing event: p:probe/generic_perform_write _stext+1237464 global_variable_for_test=@global_variable_for_test+0:s32 probe:generic_perform_write (on generic_perform_write with global_variable_for_test) You can now use it in all perf tools, such as: perf record -e probe:generic_perform_write -aR sleep 1 Signed-off-by: He Kuang <> Acked-by: Masami Hiramatsu <> Cc: Paul Mackerras <> Cc: Peter Zijlstra <> Cc: Wang Nan <> Link: Signed-off-by: Arnaldo Carvalho de Melo <>
1 files changed, 3 insertions, 1 deletions
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 44554c3c2220..1c3cc07937d5 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -578,10 +578,12 @@ static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
/* Search child die for local variables and parameters. */
if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
/* Search again in global variables */
- if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die))
+ if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
+ 0, &vr_die)) {
pr_warning("Failed to find '%s' in this function.\n",
ret = -ENOENT;
+ }
if (ret >= 0)
ret = convert_variable(&vr_die, pf);