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Thu, 23 Jul 2026 19:55:32 -0700 (PDT) From: kr494167@gmail.com To: andy@kernel.org, geert@linux-m68k.org Cc: chris.packham@alliedtelesis.co.nz, linux-kernel@vger.kernel.org, Surendra Singh Chouhan Subject: [PATCH] auxdisplay: seg-led-gpio: fix work initialization race and convert to devm_add_action_or_reset() Date: Fri, 24 Jul 2026 08:25:24 +0530 Message-ID: <20260724025524.12726-1-kr494167@gmail.com> X-Mailer: git-send-email 2.55.0 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" From: Surendra Singh Chouhan INIT_DELAYED_WORK(&priv->work, seg_led_update) was previously called inside seg_led_linedisp_get_map_type(), which is invoked during/after linedisp_register(). Initializing a delayed_work structure inside a map query callback can re-initialize an active work item or race with seg_led_linedisp_update(). In addition, seg_led_remove() called cancel_delayed_work_sync(&priv->work) before linedisp_unregister(&priv->linedisp), allowing sysfs updates to reschedule work after cancel_delayed_work_sync() completed. Fix these by moving INIT_DELAYED_WORK() to probe() and using devm_add_action_or_reset() for devm-managed cleanup. Registering seg_led_unregister_linedisp after seg_led_cancel_work ensures proper LIFO teardown order (sysfs interface unregistered first, followed by work cancellation), allowing seg_led_remove() to be removed entirely. Fixes: 899383f9ecf5 ("auxdisplay: Add 7-segment LED display driver") Signed-off-by: Surendra Singh Chouhan Reviewed-by: Chris Packham Tested-by: Chris Packham --- drivers/auxdisplay/seg-led-gpio.c | 35 +++++++++++++++++++++---------- 1 file changed, 24 insertions(+), 11 deletions(-) diff --git a/drivers/auxdisplay/seg-led-gpio.c b/drivers/auxdisplay/seg-led= -gpio.c index bc463118fe51..c83246309701 100644 --- a/drivers/auxdisplay/seg-led-gpio.c +++ b/drivers/auxdisplay/seg-led-gpio.c @@ -40,9 +40,6 @@ static void seg_led_update(struct work_struct *work) =20 static int seg_led_linedisp_get_map_type(struct linedisp *linedisp) { - struct seg_led_priv *priv =3D container_of(linedisp, struct seg_led_priv,= linedisp); - - INIT_DELAYED_WORK(&priv->work, seg_led_update); return LINEDISP_MAP_SEG7; } =20 @@ -58,10 +55,25 @@ static const struct linedisp_ops seg_led_linedisp_ops = =3D { .update =3D seg_led_linedisp_update, }; =20 +static void seg_led_cancel_work(void *data) +{ + struct seg_led_priv *priv =3D data; + + cancel_delayed_work_sync(&priv->work); +} + +static void seg_led_unregister_linedisp(void *data) +{ + struct seg_led_priv *priv =3D data; + + linedisp_unregister(&priv->linedisp); +} + static int seg_led_probe(struct platform_device *pdev) { struct seg_led_priv *priv; struct device *dev =3D &pdev->dev; + int ret; =20 priv =3D devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); if (!priv) @@ -76,15 +88,17 @@ static int seg_led_probe(struct platform_device *pdev) if (priv->segment_gpios->ndescs < 7 || priv->segment_gpios->ndescs > 8) return -EINVAL; =20 - return linedisp_register(&priv->linedisp, dev, 1, &seg_led_linedisp_ops); -} + INIT_DELAYED_WORK(&priv->work, seg_led_update); =20 -static void seg_led_remove(struct platform_device *pdev) -{ - struct seg_led_priv *priv =3D platform_get_drvdata(pdev); + ret =3D devm_add_action_or_reset(dev, seg_led_cancel_work, priv); + if (ret) + return ret; =20 - cancel_delayed_work_sync(&priv->work); - linedisp_unregister(&priv->linedisp); + ret =3D linedisp_register(&priv->linedisp, dev, 1, &seg_led_linedisp_ops); + if (ret) + return ret; + + return devm_add_action_or_reset(dev, seg_led_unregister_linedisp, priv); } =20 static const struct of_device_id seg_led_of_match[] =3D { @@ -95,7 +109,6 @@ MODULE_DEVICE_TABLE(of, seg_led_of_match); =20 static struct platform_driver seg_led_driver =3D { .probe =3D seg_led_probe, - .remove =3D seg_led_remove, .driver =3D { .name =3D "seg-led-gpio", .of_match_table =3D seg_led_of_match, --=20 2.55.0