From 763127e5b3cc2f738154e9088c3d265cc9d7091c Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 5 Nov 2019 09:16:49 +0900 Subject: [PATCH] perf probe: Return a better scope DIE if there is no best scope [ Upstream commit c701636aeec4c173208697d68da6e4271125564b ] Make find_best_scope() returns innermost DIE at given address if there is no best matched scope DIE. Since Gcc sometimes generates intuitively strange line info which is out of inlined function address range, we need this fixup. Without this, sometimes perf probe failed to probe on a line inside an inlined function: # perf probe -D ksys_open:3 Failed to find scope of probe point. Error: Failed to add events. With this fix, 'perf probe' can probe it: # perf probe -D ksys_open:3 p:probe/ksys_open _text+25707308 p:probe/ksys_open_1 _text+25710596 p:probe/ksys_open_2 _text+25711114 p:probe/ksys_open_3 _text+25711343 p:probe/ksys_open_4 _text+25714058 p:probe/ksys_open_5 _text+2819653 p:probe/ksys_open_6 _text+2819701 Signed-off-by: Masami Hiramatsu Tested-by: Arnaldo Carvalho de Melo Cc: Namhyung Kim Cc: Ravi Bangoria Cc: Steven Rostedt (VMware) Cc: Tom Zanussi Link: http://lore.kernel.org/lkml/157291300887.19771.14936015360963292236.stgit@devnote2 Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin --- tools/perf/util/probe-finder.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c index 946b027b45e8..7ccabb891e5a 100644 --- a/tools/perf/util/probe-finder.c +++ b/tools/perf/util/probe-finder.c @@ -764,6 +764,16 @@ static int find_best_scope_cb(Dwarf_Die *fn_die, void *data) return 0; } +/* Return innermost DIE */ +static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data) +{ + struct find_scope_param *fsp = data; + + memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die)); + fsp->found = true; + return 1; +} + /* Find an appropriate scope fits to given conditions */ static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem) { @@ -775,8 +785,13 @@ static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem) .die_mem = die_mem, .found = false, }; + int ret; - cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp); + ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, + &fsp); + if (!ret && !fsp.found) + cu_walk_functions_at(&pf->cu_die, pf->addr, + find_inner_scope_cb, &fsp); return fsp.found ? die_mem : NULL; } -- 2.11.0