Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 3b4694de authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo
Browse files

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: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent ea187cfb

tools/perf/util/probe-finder.c

+55 −30
Original line number Diff line number Diff line
@@ -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 @@ static Dwarf *dwfl_init_offline_dwarf(int fd, Dwfl **dwflp, Dwarf_Addr *bias) 
	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 */