From: Elena Reshetova <[email protected]> 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 <[email protected]> Signed-off-by: David Windsor <[email protected]> Signed-off-by: Hans Liljestrand <[email protected]> Signed-off-by: Kees Kook <[email protected]> Tested-by: Arnaldo Carvalho de Melo <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Andrew Morton <[email protected]> Cc: David Windsor <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Hans Liljestrand <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Kees Kook <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Matija Glavinic Pecotic <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] [ Reinstated comm_str__get() function, needed when reusing entries in the rbtree ] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> --- tools/perf/util/comm.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/tools/perf/util/comm.c b/tools/perf/util/comm.c index 21b7ff382c3f..32837b6f7879 100644 --- a/tools/perf/util/comm.c +++ b/tools/perf/util/comm.c @@ -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; -- 2.9.3
