Re: [PATCH 11/17] perf tools: Remove the node from rblist in strlist__remove

[David Ahern]

This one needs to go through urgent.


On 9/5/12 5:08 PM, Arnaldo Carvalho de Melo wrote:
> From: Suzuki K. Poulose <suzuki@xxxxxxxxxx>
>
> The following commit:
>
> author	David Ahern <dsahern@xxxxxxxxx>
> 	Tue, 31 Jul 2012 04:31:33 +0000 (22:31 -0600)
> committer	Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> 	Fri, 3 Aug 2012 13:39:51 +0000 (10:39 -0300)
> commit	ee8dd3ca43f151d9fbe1edeef68fb8a77eb9f047
>
> causes a double free during a probe deletion as the node is never
> removed from the list via strlist__remove(), even though it gets
> 'deleted' (read free()'d). This causes a double free when we do
> strlist__delete() as the node is already deleted but present in the
> rblist.
>
> [suzukikp@suzukikp perf]$ sudo ./perf probe -a do_fork
> Added new event:
>    probe:do_fork        (on do_fork)
>
> You can now use it in all perf tools, such as:
>
> 	perf record -e probe:do_fork -aR sleep 1
>
> [suzukikp@suzukikp perf]$ sudo ./perf probe -d do_fork
> Removed event: probe:do_fork
> *** glibc detected *** ./perf: double free or corruption (fasttop): 0x000000000133d600 ***
> ======= Backtrace: =========
> /lib64/libc.so.6[0x38eec7dda6]
> ./perf(rblist__delete+0x5c)[0x47d3dc]
> ./perf(del_perf_probe_events+0xb6)[0x47b826]
> ./perf(cmd_probe+0x471)[0x42c8d1]
> ./perf[0x4150b3]
> ./perf(main+0x501)[0x4148e1]
> /lib64/libc.so.6(__libc_start_main+0xed)[0x38eec2169d]
> ./perf[0x414a61]
>
> Make sure we remove the node from the rblist before we delete the node.
> The rblist__remove_node() will invoke rblist->node_delete, which  will
> take care of deleting the node with the suitable function provided by
> the user.
>
> Reported-by: Ananth N. Mavinakayanahalli <ananth@xxxxxxxxxx>
> Signed-off-by: Suzuki K. Poulose <suzuki@xxxxxxxxxx>
> Acked-by: David Ahern <dsahern@xxxxxxxxx>
> Cc: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx>
> Cc: David Ahern <dsahern@xxxxxxxxx>
> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Link: http://lkml.kernel.org/r/20120829055840.7802.1459.stgit@xxxxxxxxxxxxxxxxxxx
> Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> ---
>   tools/perf/util/strlist.c |    2 +-
>   1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/tools/perf/util/strlist.c b/tools/perf/util/strlist.c
> index 95856ff..155d8b7 100644
> --- a/tools/perf/util/strlist.c
> +++ b/tools/perf/util/strlist.c
> @@ -93,7 +93,7 @@ out:
>
>   void strlist__remove(struct strlist *slist, struct str_node *snode)
>   {
> -	str_node__delete(snode, slist->dupstr);
> +	rblist__remove_node(&slist->rblist, &snode->rb_node);
>   }
>
>   struct str_node *strlist__find(struct strlist *slist, const char *entry)

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