On 7/14/20 6:01 PM, Markus Armbruster wrote:
> Commit e8c9e65816 "qom: Make "info qom-tree" show children sorted"
> created a memory leak, because I didn't realize
> object_get_canonical_path_component()'s value needs to be freed.
>
> Reproducer:
>
> $ qemu-system-x86_64 -nodefaults -display none -S -monitor stdio
> QEMU 5.0.50 monitor - type 'help' for more information
> (qemu) info qom-tree
>
> This leaks some 4500 path components, 12-13 characters on average,
> i.e. roughly 100kBytes depending on the allocator. A couple of
> hundred "info qom-tree" here, a couple of hundred there, and soon
> enough we're talking about real memory.
>
> Plug the leak.
>
> Fixes: e8c9e65816f5dbfe18ad3b2be938d0d8192d459a
> Signed-off-by: Markus Armbruster <arm...@redhat.com>
> ---
> qom/qom-hmp-cmds.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/qom/qom-hmp-cmds.c b/qom/qom-hmp-cmds.c
> index 9ed8bb1c9f..aaacadacca 100644
> --- a/qom/qom-hmp-cmds.c
> +++ b/qom/qom-hmp-cmds.c
> @@ -96,8 +96,10 @@ static void print_qom_composition(Monitor *mon, Object
> *obj, int indent);
>
> static int qom_composition_compare(const void *a, const void *b, void
> *ignore)
> {
> - return g_strcmp0(a ? object_get_canonical_path_component(a) : NULL,
> - b ? object_get_canonical_path_component(b) : NULL);
> + g_autofree char *ac = object_get_canonical_path_component(a);
> + g_autofree char *bc = object_get_canonical_path_component(b);
> +
> + return g_strcmp0(ac, bc);
> }
>
> static int insert_qom_composition_child(Object *obj, void *opaque)
>
Li Qiang set this too:
https://lists.gnu.org/archive/html/qemu-devel/2020-07/msg04732.html
