On Fri, Jul 15, 2016 at 06:15:11PM +0800, Song Shan Gong wrote:
> At preset, when creating module's map, perf gets 'start' address by parsing
> '/proc/modules', but it's module base address, isn't the start address of
> '.text' section. In most archs, it's OK. But for s390, it places 'GOT' and
> 'PLT' relocations before '.text' section. So there exists an offset between
> module base address and '.text' section, which will incur wrong symbol
> resolution for modules.
>
> Fix this bug by getting 'start' address of module's map from parsing
> '/sys/module/[module name]/sections/.text', not from '/proc/modules'.
>
> Signed-off-by: Song Shan Gong <gon...@linux.vnet.ibm.com>
> ---
> tools/perf/arch/s390/util/Build | 2 ++
> tools/perf/arch/s390/util/sym-handling.c | 27 +++++++++++++++++++++++++++
> tools/perf/util/machine.c | 8 ++++++++
> tools/perf/util/machine.h | 1 +
> 4 files changed, 38 insertions(+)
> create mode 100644 tools/perf/arch/s390/util/sym-handling.c
>
> diff --git a/tools/perf/arch/s390/util/Build b/tools/perf/arch/s390/util/Build
> index 8a61372..5e322ed 100644
> --- a/tools/perf/arch/s390/util/Build
> +++ b/tools/perf/arch/s390/util/Build
> @@ -2,3 +2,5 @@ libperf-y += header.o
> libperf-y += kvm-stat.o
>
> libperf-$(CONFIG_DWARF) += dwarf-regs.o
> +
> +libperf-y += sym-handling.o
> diff --git a/tools/perf/arch/s390/util/sym-handling.c
> b/tools/perf/arch/s390/util/sym-handling.c
> new file mode 100644
> index 0000000..ff51336
> --- /dev/null
> +++ b/tools/perf/arch/s390/util/sym-handling.c
> @@ -0,0 +1,27 @@
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <unistd.h>
> +#include "util.h"
> +#include "machine.h"
> +#include "api/fs/fs.h"
> +
> +int arch__fix_module_text_start(u64 *start, const char *name)
> +{
> + char path[PATH_MAX];
> + char *module_name = NULL;
> + int len;
> +
> + if (!(module_name = strdup(name)))
> + return -1;
> +
> + len = strlen(module_name);
> + module_name[len - 1] = '\0';
> + snprintf(path, PATH_MAX, "module/%s/sections/.text",
> + module_name + 1);
why can't you use 'name' in here? I can't see the reason
you allocated module_name..
> +
> + if (sysfs__read_ull(path, (unsigned long long *)start) < 0) {
> + free(module_name);
> + return -1;
> + }
leaking module_name in here
> + return 0;
> +}
SNIP
thanks,
jirka
