Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 6df74bc0 authored by Elena Reshetova's avatar Elena Reshetova Committed by Arnaldo Carvalho de Melo
Browse files

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: default avatarElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: default avatarDavid Windsor <dwindsor@gmail.com>
Signed-off-by: default avatarHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: default avatarKees Kook <keescook@chromium.org>
Tested-by: default avatarArnaldo 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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent ec09a42a

tools/perf/util/comm.c

+6 −9
Original line number Diff line number Diff line
@@ -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;