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Mon, 03 Aug 2026 03:46:52 -0700 (PDT) From: Rui Miguel Silva X-Google-Original-From: "Rui Miguel Silva" Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Mon, 03 Aug 2026 11:46:51 +0100 Message-Id: Subject: Re: [PATCH v2] staging: greybus: light: fix leak of cdev->name To: "Cong Nguyen" , "Rui Miguel Silva" , "Johan Hovold" , "Alex Elder" , "Greg Kroah-Hartman" Cc: , , References: <20260802060149.3803224-1-congnt264@gmail.com> In-Reply-To: <20260802060149.3803224-1-congnt264@gmail.com> Hi Cong, Thanks for the patch. On Sun Aug 2, 2026 at 7:01 AM WEST, Cong Nguyen wrote: > gb_lights_channel_config() builds the LED classdev name with kasprintf() > and stores it in cdev->name for every channel during the configuration > phase, which runs before the channel is registered. > > That name was only released by __gb_lights_led_unregister(), i.e. only fo= r > a normal LED channel that was actually registered. It was therefore leake= d > in two cases: > > - a channel that is configured but never registered, e.g. > channel_attr_groups_set() fails, the flash configuration fails, or a > later channel in the same light fails to configure and the whole ligh= t > is torn down; the release path calls gb_lights_channel_unregister() > (which returns early because the channel is not registered) and then > gb_lights_channel_free(); > > - a flash, torch or indicator channel, whose unregister path > (__gb_lights_flash_led_unregister()) never releases cdev->name at all= , > so the name leaks even on a successful teardown. > > cdev->name is a configuration-phase allocation, like channel->color_name > and channel->mode_name. Free it in gb_lights_channel_free() next to > those, since that runs unconditionally on every teardown path, and drop > the special case free from __gb_lights_led_unregister(). > gb_lights_channel_unregister() is only ever called from > gb_lights_channel_release(), immediately followed by > gb_lights_channel_free(), so the name is still released on the registered > path and is freed exactly once. > > Commit 04820da21050 ("staging: greybus: light: Release memory obtained by > kasprintf") fixed the leak for the registered normal-LED path only; this > covers the remaining cases. > > Fixes: 2870b52bae4c ("greybus: lights: add lights implementation") > Assisted-by: Claude:claude-opus-4 > Signed-off-by: Cong Nguyen Good Catch, LGTM. Reviewed-by: Rui Miguel Silva Cheers, RUi > --- > Changes in v2: > - Add Assisted-by: tag to document AI assistance, per > Documentation/process/coding-assistants.rst (Greg KH). > - No functional change. > > drivers/staging/greybus/light.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/staging/greybus/light.c b/drivers/staging/greybus/li= ght.c > index cab02b5da867..1ecca479b5f4 100644 > --- a/drivers/staging/greybus/light.c > +++ b/drivers/staging/greybus/light.c > @@ -905,8 +905,6 @@ static void __gb_lights_led_unregister(struct gb_chan= nel *channel) > return; > =20 > led_classdev_unregister(cdev); > - kfree(cdev->name); > - cdev->name =3D NULL; > channel->led =3D NULL; > } > =20 > @@ -1063,6 +1061,9 @@ static int gb_lights_light_register(struct gb_light= *light) > =20 > static void gb_lights_channel_free(struct gb_channel *channel) > { > + struct led_classdev *cdev =3D get_channel_cdev(channel); > + > + kfree(cdev->name); > kfree(channel->attrs); > kfree(channel->attr_group); > kfree(channel->attr_groups); > --=20 > 2.25.1