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perf comm: Convert comm_str.refcnt from atomic_t to refcount_t 

The refcount_t type and corresponding API should be used instead of
atomic_t when the variable is used as a reference counter.

This allows to avoid accidental refcounter overflows that might lead to
use-after-free situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Kook <keescook@chromium.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Windsor <dwindsor@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hans Liljestrand <ishkamiel@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kees Kook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nokia.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: alsa-devel@alsa-project.org
Link: http://lkml.kernel.org/r/1487691303-31858-4-git-send-email-elena.reshetova@intel.com
[ Reinstated comm_str__get() function, needed when reusing entries in the rbtree ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Elena Reshetova 2017-02-21 17:34:57 +02:00 committed by Arnaldo Carvalho de Melo
parent ec09a42a6d
commit 6df74bc08b
1 changed files with 6 additions and 9 deletions
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15
tools/perf/util/comm.c
View File

@ -2,12 +2,12 @@
#include "util.h"
#include <stdlib.h>
#include <stdio.h>
#include <linux/atomic.h>
#include <linux/refcount.h>
struct comm_str {
char *str;
struct rb_node rb_node;
atomic_t refcnt;
refcount_t refcnt;
};
/* Should perhaps be moved to struct machine */
@ -16,13 +16,13 @@ static struct rb_root comm_str_root;
static struct comm_str *comm_str__get(struct comm_str *cs)
{
if (cs)
atomic_inc(&cs->refcnt);
refcount_inc(&cs->refcnt);
return cs;
}
static void comm_str__put(struct comm_str *cs)
{
if (cs && atomic_dec_and_test(&cs->refcnt)) {
if (cs && refcount_dec_and_test(&cs->refcnt)) {
rb_erase(&cs->rb_node, &comm_str_root);
zfree(&cs->str);
free(cs);
@ -43,7 +43,7 @@ static struct comm_str *comm_str__alloc(const char *str)
return NULL;
}
atomic_set(&cs->refcnt, 0);
refcount_set(&cs->refcnt, 1);
return cs;
}
@ -61,7 +61,7 @@ static struct comm_str *comm_str__findnew(const char *str, struct rb_root *root)
cmp = strcmp(str, iter->str);
if (!cmp)
return iter;
return comm_str__get(iter);
if (cmp < 0)
p = &(*p)->rb_left;
@ -95,8 +95,6 @@ struct comm *comm__new(const char *str, u64 timestamp, bool exec)
return NULL;
}
comm_str__get(comm->comm_str);
return comm;
}
@ -108,7 +106,6 @@ int comm__override(struct comm *comm, const char *str, u64 timestamp, bool exec)
if (!new)
return -ENOMEM;
comm_str__get(new);
comm_str__put(old);
comm->comm_str = new;
comm->start = timestamp;