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perf evlist: Convert perf_map.refcnt from atomic_t to refcount_t

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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/1487691303-31858-8-git-send-email-elena.reshetova@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Elena Reshetova 2017-02-21 17:35:01 +02:00 committed by Arnaldo Carvalho de Melo
parent ead05e8f3f
commit 25a3720cf4
2 changed files with 11 additions and 11 deletions
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18
tools/perf/util/evlist.c
View File

@ -777,7 +777,7 @@ union perf_event *perf_mmap__read_forward(struct perf_mmap *md, bool check_messu
/*
* Check if event was unmapped due to a POLLHUP/POLLERR.
*/
if (!atomic_read(&md->refcnt))
if (!refcount_read(&md->refcnt))
return NULL;
head = perf_mmap__read_head(md);
@ -794,7 +794,7 @@ perf_mmap__read_backward(struct perf_mmap *md)
/*
* Check if event was unmapped due to a POLLHUP/POLLERR.
*/
if (!atomic_read(&md->refcnt))
if (!refcount_read(&md->refcnt))
return NULL;
head = perf_mmap__read_head(md);
@ -856,7 +856,7 @@ void perf_mmap__read_catchup(struct perf_mmap *md)
{
u64 head;
if (!atomic_read(&md->refcnt))
if (!refcount_read(&md->refcnt))
return;
head = perf_mmap__read_head(md);
@ -875,14 +875,14 @@ static bool perf_mmap__empty(struct perf_mmap *md)
static void perf_mmap__get(struct perf_mmap *map)
{
atomic_inc(&map->refcnt);
refcount_inc(&map->refcnt);
}
static void perf_mmap__put(struct perf_mmap *md)
{
BUG_ON(md->base && atomic_read(&md->refcnt) == 0);
BUG_ON(md->base && refcount_read(&md->refcnt) == 0);
if (atomic_dec_and_test(&md->refcnt))
if (refcount_dec_and_test(&md->refcnt))
perf_mmap__munmap(md);
}
@ -894,7 +894,7 @@ void perf_mmap__consume(struct perf_mmap *md, bool overwrite)
perf_mmap__write_tail(md, old);
}
if (atomic_read(&md->refcnt) == 1 && perf_mmap__empty(md))
if (refcount_read(&md->refcnt) == 1 && perf_mmap__empty(md))
perf_mmap__put(md);
}
@ -937,7 +937,7 @@ static void perf_mmap__munmap(struct perf_mmap *map)
munmap(map->base, perf_mmap__mmap_len(map));
map->base = NULL;
map->fd = -1;
atomic_set(&map->refcnt, 0);
refcount_set(&map->refcnt, 0);
}
auxtrace_mmap__munmap(&map->auxtrace_mmap);
}
@ -1001,7 +1001,7 @@ static int perf_mmap__mmap(struct perf_mmap *map,
* evlist layer can't just drop it when filtering events in
* perf_evlist__filter_pollfd().
*/
atomic_set(&map->refcnt, 2);
refcount_set(&map->refcnt, 2);
map->prev = 0;
map->mask = mp->mask;
map->base = mmap(NULL, perf_mmap__mmap_len(map), mp->prot,

4
tools/perf/util/evlist.h
View File

@ -1,7 +1,7 @@
#ifndef __PERF_EVLIST_H
#define __PERF_EVLIST_H 1
#include <linux/atomic.h>
#include <linux/refcount.h>
#include <linux/list.h>
#include <api/fd/array.h>
#include <stdio.h>
@ -29,7 +29,7 @@ struct perf_mmap {
void *base;
int mask;
int fd;
atomic_t refcnt;
refcount_t refcnt;
u64 prev;
struct auxtrace_mmap auxtrace_mmap;
char event_copy[PERF_SAMPLE_MAX_SIZE] __attribute__((aligned(8)));