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Date: Thu, 9 Apr 2015 13:52:31 +0200
From: Jiri Olsa <jolsa@...hat.com>
To: Wang Nan <wangnan0@...wei.com>
Cc: acme@...nel.org, jolsa@...nel.org, namhyung@...nel.org,
mingo@...hat.com, lizefan@...wei.com, pi3orama@....com,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 2/2] perf: report/annotate: fix segfault problem.
On Wed, Apr 08, 2015 at 03:52:18AM +0000, Wang Nan wrote:
SNIP
>
> -bool is_kernel_module(const char *pathname)
> +bool is_kernel_module(const char *pathname, int cpumode)
> {
> struct kmod_path m;
>
> - if (kmod_path__parse(&m, pathname))
> + if (kmod_path__parse(&m, pathname, cpumode))
> return NULL;
>
> return m.kmod;
> @@ -210,21 +210,56 @@ bool dso__needs_decompress(struct dso *dso)
> * Returns 0 if there's no strdup error, -ENOMEM otherwise.
> */
> int __kmod_path__parse(struct kmod_path *m, const char *path,
> - bool alloc_name, bool alloc_ext)
> + int cpumode, bool alloc_name, bool alloc_ext)
> {
> const char *name = strrchr(path, '/');
> const char *ext = strrchr(path, '.');
> + bool is_simple_name = false;
> + bool cpu_mode_kernel, cpu_mode_unknown = false, is_kernel = false;
> +
> + /* treat PERF_RECORD_MISC_CPUMODE_UNKNOWN as kernel. */
> + switch (cpumode & PERF_RECORD_MISC_CPUMODE_MASK) {
> + case PERF_RECORD_MISC_USER:
> + case PERF_RECORD_MISC_HYPERVISOR:
> + case PERF_RECORD_MISC_GUEST_USER:
> + cpu_mode_kernel = false;
> + break;
> + case PERF_RECORD_MISC_CPUMODE_UNKNOWN:
> + cpu_mode_unknown = true;
> + /* fall through */
> + default:
> + cpu_mode_kernel = true;
> + }
so the cpumode is valid only for the is_kernel_module caller,
the rest of the users use PERF_RECORD_MISC_CPUMODE_UNKNOWN
could you move this logic into is_kernel_module function
and let __kmod_path__parse do only parsing work..?
also new test for is_kernel_module functionality would be nice ;-)
>
> memset(m, 0x0, sizeof(*m));
> name = name ? name + 1 : path;
>
> + /*
> + * '.' is also a valid character. For example: [aaa.bbb] is a
> + * valid module name. '[' should have higher priority than
> + * '.ko' suffix.
> + *
> + * The kernel names are from machine__mmap_name. Such
> + * name should belong to kernel itself, not kernel module.
> + */
> + if (name[0] == '[') {
> + is_simple_name = true;
> + if ((strncmp(name, "[kernel.kallsyms]", 17) == 0) ||
> + (strncmp(name, "[guest.kernel.kallsyms", 22) == 0)) {
these checks would stay in here together with checks
for [vdso] and [vsyscall] right?
SNIP
> bool is_supported_compression(const char *ext);
> -bool is_kernel_module(const char *pathname);
> +bool is_kernel_module(const char *pathname, int cpumode);
> bool decompress_to_file(const char *ext, const char *filename, int output_fd);
> bool dso__needs_decompress(struct dso *dso);
>
> @@ -228,11 +228,13 @@ struct kmod_path {
> };
>
> int __kmod_path__parse(struct kmod_path *m, const char *path,
> - bool alloc_name, bool alloc_ext);
> + int cpumode, bool alloc_name, bool alloc_ext);
>
> -#define kmod_path__parse(__m, __p) __kmod_path__parse(__m, __p, false, false)
> -#define kmod_path__parse_name(__m, __p) __kmod_path__parse(__m, __p, true , false)
> -#define kmod_path__parse_ext(__m, __p) __kmod_path__parse(__m, __p, false, true)
> +#define kmod_path__parse(__m, __p, __c) __kmod_path__parse(__m, __p, __c, false, false)
> +#define kmod_path__parse_name(__m, __p) __kmod_path__parse(__m, __p, \
> + PERF_RECORD_MISC_CPUMODE_UNKNOWN, true , false)
> +#define kmod_path__parse_ext(__m, __p) __kmod_path__parse(__m, __p, \
> + PERF_RECORD_MISC_CPUMODE_UNKNOWN, false, true)
>
> /*
> * The dso__data_* external interface provides following functions:
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index fb43215..d106e12 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -1266,7 +1266,7 @@ static int __event_process_build_id(struct build_id_event *bev,
>
> dso__set_build_id(dso, &bev->build_id);
>
> - if (!is_kernel_module(filename))
> + if (!is_kernel_module(filename, misc))
please pass either whole misc or just cpumode like you do below
in machine__process_kernel_mmap_event
however the is_kernel_module declaration says cpumode so
I'd expect cpumode, not complete misc
> dso->kernel = dso_type;
>
> build_id__sprintf(dso->build_id, sizeof(dso->build_id),
> diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
> index e45c8f3..e084943 100644
> --- a/tools/perf/util/machine.c
> +++ b/tools/perf/util/machine.c
> @@ -1109,7 +1109,9 @@ static int machine__process_kernel_mmap_event(struct machine *machine,
> struct dso *dso;
>
> list_for_each_entry(dso, &machine->kernel_dsos.head, node) {
> - if (is_kernel_module(dso->long_name))
> + if (is_kernel_module(dso->long_name,
> + event->header.misc &
> + PERF_RECORD_MISC_CPUMODE_MASK))
> continue;
>
> kernel = dso;
> --
> 1.8.3.4
>
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