lkml.org 
[lkml]   [2023]   [Apr]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH v7 2/5] perf cpumap: Add reference count checking
Em Tue, Apr 11, 2023 at 03:19:06PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Fri, Apr 07, 2023 at 04:04:02PM -0700, Ian Rogers escreveu:
> > This change is intended to catch:
> > - use after put: using a cpumap after you have put it will cause a
> > segv.
> > - unbalanced puts: two puts for a get will result in a double free
> > that can be captured and reported by tools like address sanitizer,
> > including with the associated stack traces of allocation and frees.
> > - missing puts: if a put is missing then the get turns into a memory
> > leak that can be reported by leak sanitizer, including the stack
> > trace at the point the get occurs.

> I think this should be further split into self contained patches as it
> does:

> These are missing convertions that should be in a separate patch, no?
>
> > @@ -239,7 +236,7 @@ struct cpu_aggr_map *cpu_aggr_map__new(const struct perf_cpu_map *cpus,
> > {
> > int idx;
> > struct perf_cpu cpu;
> > - struct cpu_aggr_map *c = cpu_aggr_map__empty_new(cpus->nr);
> > + struct cpu_aggr_map *c = cpu_aggr_map__empty_new(perf_cpu_map__nr(cpus));
> >
> > if (!c)
> > return NULL;

Extracted this from your larger patch:

From f8a23fce48400168be0cc078a0b0bd0e7d4a889f Mon Sep 17 00:00:00 2001
From: Ian Rogers <irogers@google.com>
Date: Wed, 12 Apr 2023 12:45:45 -0300
Subject: [PATCH 1/1] perf cpumap: Use perf_cpu_map__nr(cpus) to access
cpus->nr

So that we can have a single point where to refcount check 'struct perf_cpu_map'
instances for use after free, etc.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Link: https://lore.kernel.org/lkml/
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/cpumap.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c
index 5e564974fba4ffab..c8484b75413ef709 100644
--- a/tools/perf/util/cpumap.c
+++ b/tools/perf/util/cpumap.c
@@ -239,7 +239,7 @@ struct cpu_aggr_map *cpu_aggr_map__new(const struct perf_cpu_map *cpus,
{
int idx;
struct perf_cpu cpu;
- struct cpu_aggr_map *c = cpu_aggr_map__empty_new(cpus->nr);
+ struct cpu_aggr_map *c = cpu_aggr_map__empty_new(perf_cpu_map__nr(cpus));

if (!c)
return NULL;
@@ -263,7 +263,7 @@ struct cpu_aggr_map *cpu_aggr_map__new(const struct perf_cpu_map *cpus,
}
}
/* Trim. */
- if (c->nr != cpus->nr) {
+ if (c->nr != perf_cpu_map__nr(cpus)) {
struct cpu_aggr_map *trimmed_c =
realloc(c,
sizeof(struct cpu_aggr_map) + sizeof(struct aggr_cpu_id) * c->nr);
@@ -582,9 +582,9 @@ size_t cpu_map__snprint(struct perf_cpu_map *map, char *buf, size_t size)

#define COMMA first ? "" : ","

- for (i = 0; i < map->nr + 1; i++) {
+ for (i = 0; i < perf_cpu_map__nr(map) + 1; i++) {
struct perf_cpu cpu = { .cpu = INT_MAX };
- bool last = i == map->nr;
+ bool last = i == perf_cpu_map__nr(map);

if (!last)
cpu = map->map[i];
@@ -633,7 +633,7 @@ size_t cpu_map__snprint_mask(struct perf_cpu_map *map, char *buf, size_t size)
int i, cpu;
char *ptr = buf;
unsigned char *bitmap;
- struct perf_cpu last_cpu = perf_cpu_map__cpu(map, map->nr - 1);
+ struct perf_cpu last_cpu = perf_cpu_map__cpu(map, perf_cpu_map__nr(map) - 1);

if (buf == NULL)
return 0;
@@ -644,7 +644,7 @@ size_t cpu_map__snprint_mask(struct perf_cpu_map *map, char *buf, size_t size)
return 0;
}

- for (i = 0; i < map->nr; i++) {
+ for (i = 0; i < perf_cpu_map__nr(map); i++) {
cpu = perf_cpu_map__cpu(map, i).cpu;
bitmap[cpu / 8] |= 1 << (cpu % 8);
}
--
2.39.2
\
 
 \ /
  Last update: 2023-04-12 17:50    [W:0.070 / U:0.160 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site