2022-10-17 09:35:59

by Shang XiaoJing

Subject: [PATCH] tools lib traceevent: Fix double free in event_read_fields()

There is a double free in event_read_fields(). After calling free_token()
to free the token, if append() failed, then goto fail, which will call
free_token() again. Triggered by compiling with perf and run "perf sched
record". Fix the double free by goto fail_expect instead of fail while
append() failed, which won't call redundant free_token().

BUG: double free
free(): double free detected in tcache 2
Aborted

Fixes: d286447f23cd ("tools lib traceevent: Handle realloc() failure path")
Signed-off-by: Shang XiaoJing <[email protected]>
---
tools/lib/traceevent/event-parse.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index 8e24c4c78c7f..e0a5a22fe702 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -1594,7 +1594,7 @@ static int event_read_fields(struct tep_event *event, struct tep_format_field **
ret = append(&brackets, "", "]");
if (ret < 0) {
free(brackets);
- goto fail;
+ goto fail_expect;
}

/* add brackets to type */
--
2.17.1

2022-10-20 22:10:10

by Steven Rostedt

Subject: Re: [PATCH] tools lib traceevent: Fix double free in event_read_fields()

On Mon, 17 Oct 2022 16:59:37 +0800
Shang XiaoJing <[email protected]> wrote:

> There is a double free in event_read_fields(). After calling free_token()
> to free the token, if append() failed, then goto fail, which will call
> free_token() again. Triggered by compiling with perf and run "perf sched
> record". Fix the double free by goto fail_expect instead of fail while
> append() failed, which won't call redundant free_token().
>
> BUG: double free
> free(): double free detected in tcache 2
> Aborted
>
> Fixes: d286447f23cd ("tools lib traceevent: Handle realloc() failure path")
> Signed-off-by: Shang XiaoJing <[email protected]>
> ---
> tools/lib/traceevent/event-parse.c | 2 +-

tool/lib/traceevent is deprecated.

Can you send this patch to [email protected] against

https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/

Thanks!

-- Steve


> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
> index 8e24c4c78c7f..e0a5a22fe702 100644
> --- a/tools/lib/traceevent/event-parse.c
> +++ b/tools/lib/traceevent/event-parse.c
> @@ -1594,7 +1594,7 @@ static int event_read_fields(struct tep_event *event, struct tep_format_field **
> ret = append(&brackets, "", "]");
> if (ret < 0) {
> free(brackets);
> - goto fail;
> + goto fail_expect;
> }
>
> /* add brackets to type */

2022-10-21 01:19:48

by Shang XiaoJing

Subject: Re: [PATCH] tools lib traceevent: Fix double free in event_read_fields()

On 2022/10/21 5:23, Steven Rostedt wrote:
> On Mon, 17 Oct 2022 16:59:37 +0800
> Shang XiaoJing <[email protected]> wrote:
>
>> There is a double free in event_read_fields(). After calling free_token()
>> to free the token, if append() failed, then goto fail, which will call
>> free_token() again. Triggered by compiling with perf and run "perf sched
>> record". Fix the double free by goto fail_expect instead of fail while
>> append() failed, which won't call redundant free_token().
>>
>> BUG: double free
>> free(): double free detected in tcache 2
>> Aborted
>>
>> Fixes: d286447f23cd ("tools lib traceevent: Handle realloc() failure path")
>> Signed-off-by: Shang XiaoJing <[email protected]>
>> ---
>> tools/lib/traceevent/event-parse.c | 2 +-
>
> tool/lib/traceevent is deprecated.
>
> Can you send this patch to [email protected] against
>
> https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/
>
ok, thanks for the reminder.

Thanks,
--
Shang XiaoJing