From 2bf6a49c14e124b0a11d0d54834519fa6cc15695 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Tue, 12 May 2020 15:19:16 +0300 Subject: [PATCH] perf kcore_copy: Fix module map when there are no modules loaded [ Upstream commit 61f82e3fb697a8e85f22fdec786528af73dc36d1 ] In the absence of any modules, no "modules" map is created, but there are other executable pages to map, due to eBPF JIT, kprobe or ftrace. Map them by recognizing that the first "module" symbol is not necessarily from a module, and adjust the map accordingly. Signed-off-by: Adrian Hunter Cc: Alexander Shishkin Cc: Borislav Petkov Cc: H. Peter Anvin Cc: Jiri Olsa Cc: Leo Yan Cc: Mark Rutland Cc: Masami Hiramatsu Cc: Mathieu Poirier Cc: Peter Zijlstra Cc: Steven Rostedt (VMware) Cc: x86@kernel.org Link: http://lore.kernel.org/lkml/20200512121922.8997-10-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin --- tools/perf/util/symbol-elf.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index 5a50326c8158..e155783c601a 100644 --- a/tools/perf/util/symbol-elf.c +++ b/tools/perf/util/symbol-elf.c @@ -1421,6 +1421,7 @@ struct kcore_copy_info { u64 first_symbol; u64 last_symbol; u64 first_module; + u64 first_module_symbol; u64 last_module_symbol; struct phdr_data kernel_map; struct phdr_data modules_map; @@ -1435,6 +1436,8 @@ static int kcore_copy__process_kallsyms(void *arg, const char *name, char type, return 0; if (strchr(name, '[')) { + if (!kci->first_module_symbol || start < kci->first_module_symbol) + kci->first_module_symbol = start; if (start > kci->last_module_symbol) kci->last_module_symbol = start; return 0; @@ -1559,6 +1562,10 @@ static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir, kci->etext += page_size; } + if (kci->first_module_symbol && + (!kci->first_module || kci->first_module_symbol < kci->first_module)) + kci->first_module = kci->first_module_symbol; + kci->first_module = round_down(kci->first_module, page_size); if (kci->last_module_symbol) { -- 2.34.1