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perf probe: Fix to support libdwfl older than 0.148 

Since the libdwfl library before 0.148 fails to analyze live kernel debuginfo,
'perf probe --list' compiled with those old libdwfl sometimes 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.

Cc: 2nddept-manager@sdl.hitachi.co.jp
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20101217131218.24123.62424.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
wifi-calibration
Masami Hiramatsu 2010-12-17 22:12:18 +09:00 committed by Arnaldo Carvalho de Melo
parent ea187cfbb9
commit 3b4694de35
1 changed files with 55 additions and 30 deletions
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85
tools/perf/util/probe-finder.c
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@ -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 */