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Tue, 18 Aug 2026 19:46:15 -0700 (PDT) From: kr494167@gmail.com To: andy.shevchenko@gmail.com, andy@kernel.org, geert@linux-m68k.org Cc: chris.packham@alliedtelesis.co.nz, linux-kernel@vger.kernel.org, Surendra Singh Chouhan Subject: [PATCH 0/3 2/3] auxdisplay: seg-led-gpio: fix work initialization race and convert to devm_linedisp_register() Date: Wed, 19 Aug 2026 08:15:55 +0530 Message-ID: <20260819024556.63534-3-kr494167@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260819024556.63534-1-kr494167@gmail.com> References: <20260819024556.63534-1-kr494167@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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(), using devm_add_action_or_reset() for work cancellation, and converting to devm_linedisp_register(). Registering devm_linedisp_register() after work cancellation action 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") Reviewed-by: Chris Packham Tested-by: Chris Packham Signed-off-by: Surendra Singh Chouhan --- drivers/auxdisplay/seg-led-gpio.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/drivers/auxdisplay/seg-led-gpio.c b/drivers/auxdisplay/seg-led-gpio.c index bc463118fe51..ca39c9071688 100644 --- a/drivers/auxdisplay/seg-led-gpio.c +++ b/drivers/auxdisplay/seg-led-gpio.c @@ -38,11 +38,15 @@ static void seg_led_update(struct work_struct *work) gpiod_multi_set_value_cansleep(priv->segment_gpios, values); } -static int seg_led_linedisp_get_map_type(struct linedisp *linedisp) +static void seg_led_cancel_work(void *data) { - struct seg_led_priv *priv = container_of(linedisp, struct seg_led_priv, linedisp); + struct delayed_work *work = data; - INIT_DELAYED_WORK(&priv->work, seg_led_update); + cancel_delayed_work_sync(work); +} + +static int seg_led_linedisp_get_map_type(struct linedisp *linedisp) +{ return LINEDISP_MAP_SEG7; } @@ -62,11 +66,17 @@ static int seg_led_probe(struct platform_device *pdev) { struct seg_led_priv *priv; struct device *dev = &pdev->dev; + int ret; priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; + INIT_DELAYED_WORK(&priv->work, seg_led_update); + ret = devm_add_action_or_reset(dev, seg_led_cancel_work, &priv->work); + if (ret) + return ret; + platform_set_drvdata(pdev, priv); priv->segment_gpios = devm_gpiod_get_array(dev, "segment", GPIOD_OUT_LOW); @@ -76,15 +86,7 @@ static int seg_led_probe(struct platform_device *pdev) if (priv->segment_gpios->ndescs < 7 || priv->segment_gpios->ndescs > 8) return -EINVAL; - return linedisp_register(&priv->linedisp, dev, 1, &seg_led_linedisp_ops); -} - -static void seg_led_remove(struct platform_device *pdev) -{ - struct seg_led_priv *priv = platform_get_drvdata(pdev); - - cancel_delayed_work_sync(&priv->work); - linedisp_unregister(&priv->linedisp); + return devm_linedisp_register(dev, &priv->linedisp, 1, &seg_led_linedisp_ops); } static const struct of_device_id seg_led_of_match[] = { @@ -95,7 +97,6 @@ MODULE_DEVICE_TABLE(of, seg_led_of_match); static struct platform_driver seg_led_driver = { .probe = seg_led_probe, - .remove = seg_led_remove, .driver = { .name = "seg-led-gpio", .of_match_table = seg_led_of_match, -- 2.55.0