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Subject[037/156] perf annotate: Defer allocating sym_priv->hist array
2.6.33-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Arnaldo Carvalho de Melo <acme@infradead.org>

commit 628ada0cb03666dd463f7c25947eaccdf440c309 upstream

Because symbol->end is not fixed up at symbol_filter time, only
after all symbols for a DSO are loaded, and that, for asm
symbols, may be bogus, causing segfaults when hits happen in
these symbols.

Backported-from: 628ada0
Reported-by: David Miller <davem@davemloft.net>
Reported-by: Anton Blanchard <anton@samba.org>
Acked-by: David Miller <davem@davemloft.net>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20100225155740.GB8553@ghostprotocols.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
tools/perf/builtin-annotate.c | 65 +++++++++++++++++++++---------------------
tools/perf/util/symbol.c | 2 -
tools/perf/util/symbol.h | 2 +
3 files changed, 36 insertions(+), 33 deletions(-)

--- a/tools/perf/builtin-annotate.c
+++ b/tools/perf/builtin-annotate.c
@@ -53,32 +53,20 @@ struct sym_priv {

static const char *sym_hist_filter;

-static int symbol_filter(struct map *map __used, struct symbol *sym)
+static int sym__alloc_hist(struct symbol *self)
{
- if (sym_hist_filter == NULL ||
- strcmp(sym->name, sym_hist_filter) == 0) {
- struct sym_priv *priv = symbol__priv(sym);
- const int size = (sizeof(*priv->hist) +
- (sym->end - sym->start) * sizeof(u64));
-
- priv->hist = malloc(size);
- if (priv->hist)
- memset(priv->hist, 0, size);
- return 0;
- }
- /*
- * FIXME: We should really filter it out, as we don't want to go thru symbols
- * we're not interested, and if a DSO ends up with no symbols, delete it too,
- * but right now the kernel loading routines in symbol.c bail out if no symbols
- * are found, fix it later.
- */
- return 0;
+ struct sym_priv *priv = symbol__priv(self);
+ const int size = (sizeof(*priv->hist) +
+ (self->end - self->start) * sizeof(u64));
+
+ priv->hist = zalloc(size);
+ return priv->hist == NULL ? -1 : 0;
}

/*
* collect histogram counts
*/
-static void hist_hit(struct hist_entry *he, u64 ip)
+static int annotate__hist_hit(struct hist_entry *he, u64 ip)
{
unsigned int sym_size, offset;
struct symbol *sym = he->sym;
@@ -88,11 +76,11 @@ static void hist_hit(struct hist_entry *
he->count++;

if (!sym || !he->map)
- return;
+ return 0;

priv = symbol__priv(sym);
- if (!priv->hist)
- return;
+ if (priv->hist == NULL && sym__alloc_hist(sym) < 0)
+ return -ENOMEM;

sym_size = sym->end - sym->start;
offset = ip - sym->start;
@@ -102,7 +90,7 @@ static void hist_hit(struct hist_entry *
he->map->unmap_ip(he->map, ip));

if (offset >= sym_size)
- return;
+ return 0;

h = priv->hist;
h->sum++;
@@ -114,18 +102,31 @@ static void hist_hit(struct hist_entry *
he->sym->name,
(void *)(unsigned long)ip, ip - he->sym->start,
h->ip[offset]);
+ return 0;
}

static int perf_session__add_hist_entry(struct perf_session *self,
struct addr_location *al, u64 count)
{
- bool hit;
- struct hist_entry *he = __perf_session__add_hist_entry(self, al, NULL,
- count, &hit);
- if (he == NULL)
- return -ENOMEM;
- hist_hit(he, al->addr);
- return 0;
+ bool hit;
+ struct hist_entry *he;
+
+ if (sym_hist_filter != NULL &&
+ (al->sym == NULL || strcmp(sym_hist_filter, al->sym->name) != 0)) {
+ /* We're only interested in a symbol named sym_hist_filter */
+ if (al->sym != NULL) {
+ rb_erase(&al->sym->rb_node,
+ &al->map->dso->symbols[al->map->type]);
+ symbol__delete(al->sym);
+ }
+ return 0;
+ }
+
+ he = __perf_session__add_hist_entry(self, al, NULL, count, &hit);
+ if (he == NULL)
+ return -ENOMEM;
+
+ return annotate__hist_hit(he, al->addr);
}

static int process_sample_event(event_t *event, struct perf_session *session)
@@ -135,7 +136,7 @@ static int process_sample_event(event_t
dump_printf("(IP, %d): %d: %p\n", event->header.misc,
event->ip.pid, (void *)(long)event->ip.ip);

- if (event__preprocess_sample(event, session, &al, symbol_filter) < 0) {
+ if (event__preprocess_sample(event, session, &al, NULL) < 0) {
fprintf(stderr, "problem processing %d event, skipping it.\n",
event->header.type);
return -1;
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -149,7 +149,7 @@ static struct symbol *symbol__new(u64 st
return self;
}

-static void symbol__delete(struct symbol *self)
+void symbol__delete(struct symbol *self)
{
free(((void *)self) - symbol_conf.priv_size);
}
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -49,6 +49,8 @@ struct symbol {
char name[0];
};

+void symbol__delete(struct symbol *self);
+
struct strlist;

struct symbol_conf {

--
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