RE: [PATCH 2/2 (v2)] perf tools: Prevent calling machine__delete() on non-allocated machine

["平松雅巳 / HIRAMATU，MASAMI" <masami.hiramatsu.pt@hitachi.com>]

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Hi Wang,

>From: Wang Nan [mailto:wangnan0@huawei.com]
>
>To prevent futher commits calling machine__delete() on non-allocated
>'struct machine' (which would cause memory corruption), this patch
>enforces machine__init(), record whether a machine structure is
>dynamically allocated or not, and warn if machine__delete() is called
>on incorrect object.

Looks good to me :D

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Thanks!

>
>Signed-off-by: Wang Nan <wangnan0@huawei.com>
>Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
>Cc: Jiri Olsa <jolsa@kernel.org>
>Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
>Cc: Namhyung Kim <namhyung@kernel.org>
>---
>
>v1 -> v2: Remove incorrect '!'.
>
>---
> tools/perf/tests/vmlinux-kallsyms.c |  4 ++--
> tools/perf/util/machine.c           | 14 +++++++++-----
> tools/perf/util/machine.h           |  3 ++-
> 3 files changed, 13 insertions(+), 8 deletions(-)
>
>diff --git a/tools/perf/tests/vmlinux-kallsyms.c b/tools/perf/tests/vmlinux-kallsyms.c
>index f0bfc9e..441e93d 100644
>--- a/tools/perf/tests/vmlinux-kallsyms.c
>+++ b/tools/perf/tests/vmlinux-kallsyms.c
>@@ -35,8 +35,8 @@ int test__vmlinux_matches_kallsyms(int subtest __maybe_unused)
> 	 * Init the machines that will hold kernel, modules obtained from
> 	 * both vmlinux + .ko files and from /proc/kallsyms split by modules.
> 	 */
>-	machine__init(&kallsyms, "", HOST_KERNEL_ID);
>-	machine__init(&vmlinux, "", HOST_KERNEL_ID);
>+	machine__init(&kallsyms, "", HOST_KERNEL_ID, false);
>+	machine__init(&vmlinux, "", HOST_KERNEL_ID, false);
>
> 	/*
> 	 * Step 2:
>diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
>index f5882b8..ac64e5a 100644
>--- a/tools/perf/util/machine.c
>+++ b/tools/perf/util/machine.c
>@@ -23,7 +23,7 @@ static void dsos__init(struct dsos *dsos)
> 	pthread_rwlock_init(&dsos->lock, NULL);
> }
>
>-int machine__init(struct machine *machine, const char *root_dir, pid_t pid)
>+int machine__init(struct machine *machine, const char *root_dir, pid_t pid, bool allocated)
> {
> 	map_groups__init(&machine->kmaps, machine);
> 	RB_CLEAR_NODE(&machine->rb_node);
>@@ -64,6 +64,7 @@ int machine__init(struct machine *machine, const char *root_dir, pid_t pid)
> 	}
>
> 	machine->current_tid = NULL;
>+	machine->allocated = allocated;
>
> 	return 0;
> }
>@@ -73,7 +74,7 @@ struct machine *machine__new_host(void)
> 	struct machine *machine = malloc(sizeof(*machine));
>
> 	if (machine != NULL) {
>-		machine__init(machine, "", HOST_KERNEL_ID);
>+		machine__init(machine, "", HOST_KERNEL_ID, true);
>
> 		if (machine__create_kernel_maps(machine) < 0)
> 			goto out_delete;
>@@ -136,12 +137,15 @@ void machine__exit(struct machine *machine)
> void machine__delete(struct machine *machine)
> {
> 	machine__exit(machine);
>-	free(machine);
>+	if (machine->allocated)
>+		free(machine);
>+	else
>+		pr_warning("WARNING: delete a non-allocated machine. Skip.\n");
> }
>
> void machines__init(struct machines *machines)
> {
>-	machine__init(&machines->host, "", HOST_KERNEL_ID);
>+	machine__init(&machines->host, "", HOST_KERNEL_ID, false);
> 	machines->guests = RB_ROOT;
> 	machines->symbol_filter = NULL;
> }
>@@ -162,7 +166,7 @@ struct machine *machines__add(struct machines *machines, pid_t pid,
> 	if (machine == NULL)
> 		return NULL;
>
>-	if (machine__init(machine, root_dir, pid) != 0) {
>+	if (machine__init(machine, root_dir, pid, true) != 0) {
> 		free(machine);
> 		return NULL;
> 	}
>diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h
>index 2c2b443..24dfd46 100644
>--- a/tools/perf/util/machine.h
>+++ b/tools/perf/util/machine.h
>@@ -28,6 +28,7 @@ struct machine {
> 	pid_t		  pid;
> 	u16		  id_hdr_size;
> 	bool		  comm_exec;
>+	bool		  allocated;
> 	char		  *root_dir;
> 	struct rb_root	  threads;
> 	pthread_rwlock_t  threads_lock;
>@@ -131,7 +132,7 @@ void machines__set_symbol_filter(struct machines *machines,
> void machines__set_comm_exec(struct machines *machines, bool comm_exec);
>
> struct machine *machine__new_host(void);
>-int machine__init(struct machine *machine, const char *root_dir, pid_t pid);
>+int machine__init(struct machine *machine, const char *root_dir, pid_t pid, bool allocated);
> void machine__exit(struct machine *machine);
> void machine__delete_threads(struct machine *machine);
> void machine__delete(struct machine *machine);
>--
>1.8.3.4

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