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Message-ID: <20101217131218.24123.62424.stgit@ltc236.sdl.hitachi.co.jp>
Date: Fri, 17 Dec 2010 22:12:18 +0900
From: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
To: Arnaldo Carvalho de Melo <acme@...hat.com>,
Ingo Molnar <mingo@...e.hu>
Cc: Steven Rostedt <rostedt@...dmis.org>,
Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
linux-kernel@...r.kernel.org, 2nddept-manager@....hitachi.co.jp,
Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Paul Mackerras <paulus@...ba.org>, Ingo Molnar <mingo@...e.hu>,
Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
linux-kernel@...r.kernel.org
Subject: [PATCH -tip 4/4] [BUGFIX]perf probe: Fix to support libdwfl older
than 0.148
Since the libdwfl before 0.148 fails to analyze live
kernel debuginfo, 'perf probe --list' compiled with those
old libdwfl sometime crashes.
To avoid that bug, perf probe does not use libdwfl's live
kernel analysis routine when it is compiled with older libdwfl.
Side effect: perf with older libdwfl doesn't support
listing probe in modules with source code line. Those
could be shown by symbol+offset.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Ingo Molnar <mingo@...e.hu>
Cc: Arnaldo Carvalho de Melo <acme@...stprotocols.net>
Cc: linux-kernel@...r.kernel.org
---
tools/perf/util/probe-finder.c | 85 ++++++++++++++++++++++++++--------------
1 files changed, 55 insertions(+), 30 deletions(-)
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 90b6292..ab83b6a 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -117,28 +117,6 @@ static void line_list__free(struct list_head *head)
}
/* Dwarf FL wrappers */
-
-static int __linux_kernel_find_elf(Dwfl_Module *mod,
- void **userdata,
- const char *module_name,
- Dwarf_Addr base,
- char **file_name, Elf **elfp)
-{
- int fd;
- const char *path = kernel_get_module_path(module_name);
-
- if (path) {
- fd = open(path, O_RDONLY);
- if (fd >= 0) {
- *file_name = strdup(path);
- return fd;
- }
- }
- /* If failed, try to call standard method */
- return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
- file_name, elfp);
-}
-
static char *debuginfo_path; /* Currently dummy */
static const Dwfl_Callbacks offline_callbacks = {
@@ -151,14 +129,6 @@ static const Dwfl_Callbacks offline_callbacks = {
.find_elf = dwfl_build_id_find_elf,
};
-static const Dwfl_Callbacks kernel_callbacks = {
- .find_debuginfo = dwfl_standard_find_debuginfo,
- .debuginfo_path = &debuginfo_path,
-
- .find_elf = __linux_kernel_find_elf,
- .section_address = dwfl_linux_kernel_module_section_address,
-};
-
/* Get a Dwarf from offline image */
static Dwarf *dwfl_init_offline_dwarf(int fd, Dwfl **dwflp, Dwarf_Addr *bias)
{
@@ -185,6 +155,38 @@ error:
return dbg;
}
+#if _ELFUTILS_PREREQ(0, 148)
+/* This method is buggy if elfutils is older than 0.148 */
+static int __linux_kernel_find_elf(Dwfl_Module *mod,
+ void **userdata,
+ const char *module_name,
+ Dwarf_Addr base,
+ char **file_name, Elf **elfp)
+{
+ int fd;
+ const char *path = kernel_get_module_path(module_name);
+
+ pr_debug2("Use file %s for %s\n", path, module_name);
+ if (path) {
+ fd = open(path, O_RDONLY);
+ if (fd >= 0) {
+ *file_name = strdup(path);
+ return fd;
+ }
+ }
+ /* If failed, try to call standard method */
+ return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
+ file_name, elfp);
+}
+
+static const Dwfl_Callbacks kernel_callbacks = {
+ .find_debuginfo = dwfl_standard_find_debuginfo,
+ .debuginfo_path = &debuginfo_path,
+
+ .find_elf = __linux_kernel_find_elf,
+ .section_address = dwfl_linux_kernel_module_section_address,
+};
+
/* Get a Dwarf from live kernel image */
static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr, Dwfl **dwflp,
Dwarf_Addr *bias)
@@ -205,11 +207,34 @@ static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr, Dwfl **dwflp,
dbg = dwfl_addrdwarf(*dwflp, addr, bias);
/* Here, check whether we could get a real dwarf */
if (!dbg) {
+ pr_debug("Failed to find kernel dwarf at %lx\n",
+ (unsigned long)addr);
dwfl_end(*dwflp);
*dwflp = NULL;
}
return dbg;
}
+#else
+/* With older elfutils, this just support kernel module... */
+static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr __used, Dwfl **dwflp,
+ Dwarf_Addr *bias)
+{
+ int fd;
+ const char *path = kernel_get_module_path("kernel");
+
+ if (!path) {
+ pr_err("Failed to find vmlinux path\n");
+ return NULL;
+ }
+
+ pr_debug2("Use file %s for debuginfo\n", path);
+ fd = open(path, O_RDONLY);
+ if (fd < 0)
+ return NULL;
+
+ return dwfl_init_offline_dwarf(fd, dwflp, bias);
+}
+#endif
/* Dwarf wrappers */
--
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