From d13855ef18e1852b2c4dc86ddf5759c5b34628cb Mon Sep 17 00:00:00 2001 From: He Kuang Date: Sat, 25 Apr 2015 16:08:58 +0800 Subject: [PATCH] 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: http://lkml.kernel.org/r/1429949338-18678-1-git-send-email-hekuang@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/probe-finder.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) 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", pf->pvar->var); ret = -ENOENT; + } } if (ret >= 0) ret = convert_variable(&vr_die, pf);