Re: [PATCH V2 2/9] perf tools: load kernel maps before using
From: Arnaldo Carvalho de Melo
Date: Wed Jul 31 2013 - 10:35:31 EST
Em Wed, Jul 31, 2013 at 12:13:51AM +0300, Adrian Hunter escreveu:
> In order to use kernel maps to read object code, those
> maps must be adjusted to map to the dso file offset.
> Because lazy-initialization is used, that is not done
> until symbols are loaded. However the maps are first
> used by thread__find_addr_map() before symbols are loaded.
> So this patch changes thread__find_addr() to "load" kernel
> maps before using them.
Argh, yeah, we create maps as we traverse kallsyms, right? I guess this
is there for historical reasons (i.e. it "evolved" like that), but I'm
adding a note to my TODO list to remove that mess, i.e. we should
probably do that as a separate step, i.e. the creation of kernel maps,
detached from actually loading the symbols.
For now I think your patch makes we progress, so I'll apply it.
Thanks,
- Arnaldo
> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> ---
> tools/perf/builtin-inject.c | 2 +-
> tools/perf/builtin-script.c | 4 ++--
> tools/perf/tests/code-reading.c | 2 +-
> tools/perf/util/build-id.c | 2 +-
> tools/perf/util/event.c | 18 ++++++++++++++----
> tools/perf/util/thread.h | 2 +-
> tools/perf/util/unwind.c | 4 ++--
> 7 files changed, 22 insertions(+), 12 deletions(-)
>
> diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
> index 1d8de2e..f012a98 100644
> --- a/tools/perf/builtin-inject.c
> +++ b/tools/perf/builtin-inject.c
> @@ -206,7 +206,7 @@ static int perf_event__inject_buildid(struct perf_tool *tool,
> }
>
> thread__find_addr_map(thread, machine, cpumode, MAP__FUNCTION,
> - event->ip.ip, &al);
> + event->ip.ip, &al, NULL);
>
> if (al.map != NULL) {
> if (!al.map->dso->hit) {
> diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
> index 1cad370..cd616ff 100644
> --- a/tools/perf/builtin-script.c
> +++ b/tools/perf/builtin-script.c
> @@ -341,10 +341,10 @@ static void print_sample_addr(union perf_event *event,
> return;
>
> thread__find_addr_map(thread, machine, cpumode, MAP__FUNCTION,
> - sample->addr, &al);
> + sample->addr, &al, NULL);
> if (!al.map)
> thread__find_addr_map(thread, machine, cpumode, MAP__VARIABLE,
> - sample->addr, &al);
> + sample->addr, &al, NULL);
>
> al.cpu = sample->cpu;
> al.sym = NULL;
> diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
> index 7c9437d..6cd3190 100644
> --- a/tools/perf/tests/code-reading.c
> +++ b/tools/perf/tests/code-reading.c
> @@ -138,7 +138,7 @@ static int read_object_code(u64 addr, size_t len, u8 cpumode,
> pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
>
> thread__find_addr_map(thread, machine, cpumode, MAP__FUNCTION, addr,
> - &al);
> + &al, NULL);
> if (!al.map || !al.map->dso) {
> pr_debug("thread__find_addr_map failed\n");
> return -1;
> diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
> index 5295625..3a0f508 100644
> --- a/tools/perf/util/build-id.c
> +++ b/tools/perf/util/build-id.c
> @@ -33,7 +33,7 @@ int build_id__mark_dso_hit(struct perf_tool *tool __maybe_unused,
> }
>
> thread__find_addr_map(thread, machine, cpumode, MAP__FUNCTION,
> - event->ip.ip, &al);
> + event->ip.ip, &al, NULL);
>
> if (al.map != NULL)
> al.map->dso->hit = 1;
> diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
> index 9541270..cc7c0c9 100644
> --- a/tools/perf/util/event.c
> +++ b/tools/perf/util/event.c
> @@ -592,9 +592,10 @@ int perf_event__process(struct perf_tool *tool __maybe_unused,
> void thread__find_addr_map(struct thread *self,
> struct machine *machine, u8 cpumode,
> enum map_type type, u64 addr,
> - struct addr_location *al)
> + struct addr_location *al, symbol_filter_t filter)
> {
> struct map_groups *mg = &self->mg;
> + bool load_map = false;
>
> al->thread = self;
> al->addr = addr;
> @@ -609,11 +610,13 @@ void thread__find_addr_map(struct thread *self,
> if (cpumode == PERF_RECORD_MISC_KERNEL && perf_host) {
> al->level = 'k';
> mg = &machine->kmaps;
> + load_map = true;
> } else if (cpumode == PERF_RECORD_MISC_USER && perf_host) {
> al->level = '.';
> } else if (cpumode == PERF_RECORD_MISC_GUEST_KERNEL && perf_guest) {
> al->level = 'g';
> mg = &machine->kmaps;
> + load_map = true;
> } else {
> /*
> * 'u' means guest os user space.
> @@ -654,8 +657,15 @@ try_again:
> mg = &machine->kmaps;
> goto try_again;
> }
> - } else
> + } else {
> + /*
> + * Kernel maps might be changed when loading symbols so loading
> + * must be done prior to using kernel maps.
> + */
> + if (load_map)
> + map__load(al->map, filter);
> al->addr = al->map->map_ip(al->map, al->addr);
> + }
> }
>
> void thread__find_addr_location(struct thread *thread, struct machine *machine,
> @@ -663,7 +673,7 @@ void thread__find_addr_location(struct thread *thread, struct machine *machine,
> struct addr_location *al,
> symbol_filter_t filter)
> {
> - thread__find_addr_map(thread, machine, cpumode, type, addr, al);
> + thread__find_addr_map(thread, machine, cpumode, type, addr, al, filter);
> if (al->map != NULL)
> al->sym = map__find_symbol(al->map, al->addr, filter);
> else
> @@ -699,7 +709,7 @@ int perf_event__preprocess_sample(const union perf_event *event,
> machine__create_kernel_maps(machine);
>
> thread__find_addr_map(thread, machine, cpumode, MAP__FUNCTION,
> - event->ip.ip, al);
> + event->ip.ip, al, filter);
> dump_printf(" ...... dso: %s\n",
> al->map ? al->map->dso->long_name :
> al->level == 'H' ? "[hypervisor]" : "<not found>");
> diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
> index 0fe1f9c..f98d1d9 100644
> --- a/tools/perf/util/thread.h
> +++ b/tools/perf/util/thread.h
> @@ -41,7 +41,7 @@ static inline struct map *thread__find_map(struct thread *self,
>
> void thread__find_addr_map(struct thread *thread, struct machine *machine,
> u8 cpumode, enum map_type type, u64 addr,
> - struct addr_location *al);
> + struct addr_location *al, symbol_filter_t filter);
>
> void thread__find_addr_location(struct thread *thread, struct machine *machine,
> u8 cpumode, enum map_type type, u64 addr,
> diff --git a/tools/perf/util/unwind.c b/tools/perf/util/unwind.c
> index 958723b..5bbd494 100644
> --- a/tools/perf/util/unwind.c
> +++ b/tools/perf/util/unwind.c
> @@ -272,7 +272,7 @@ static struct map *find_map(unw_word_t ip, struct unwind_info *ui)
> struct addr_location al;
>
> thread__find_addr_map(ui->thread, ui->machine, PERF_RECORD_MISC_USER,
> - MAP__FUNCTION, ip, &al);
> + MAP__FUNCTION, ip, &al, NULL);
> return al.map;
> }
>
> @@ -349,7 +349,7 @@ static int access_dso_mem(struct unwind_info *ui, unw_word_t addr,
> ssize_t size;
>
> thread__find_addr_map(ui->thread, ui->machine, PERF_RECORD_MISC_USER,
> - MAP__FUNCTION, addr, &al);
> + MAP__FUNCTION, addr, &al, NULL);
> if (!al.map) {
> pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
> return -1;
> --
> 1.7.11.7
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