From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 194D241C2F6; Wed, 4 Feb 2026 14:57:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770217040; cv=none; b=j2fD1eS/C+st7tL5Y+3+ouK2OiXTrxBymeZayTs2th03By6EJ51gjVRgy1NRLb6GlT1HKXDJLFH2sFjEIheIor43C8CO4Kq8oac1DVok0v2kFrFFmFqHwlb5vP4zuqH5jJ+peB3QsBIK5J5Ar1DZCx0lCQLc4F/P42h6HPc1Pyo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770217040; c=relaxed/simple; bh=Cz/65JQ+fB6G7rStYgIRIrKU8z5twFrbNjT++k0F8RA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JcMsrParLqCoVmDdDkybVj4VzP/WASvdP14q8OEwuxi8aeeVTBbpRecKN3/me//HZS1E67d4H99IGdwscv4GouChTgj2+BFhLufMO9Sfd/EQ+SdGyuAmeqtB/BZy8BPUmLVEyCU1IznhV0WxUpI4fERt9DPk7E+BP+sHCJFJlrE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=bEicPZtH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="bEicPZtH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7C054C4CEF7; Wed, 4 Feb 2026 14:57:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1770217040; bh=Cz/65JQ+fB6G7rStYgIRIrKU8z5twFrbNjT++k0F8RA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bEicPZtHBs1NunfIhBWFx1bImG2KDS9Ps8wS/o3QNX8u0ruejtIey31SU5NcagdTo MtsQ2rc1a6duhZa8R+N+0OboFM/DmkfOYIQC1GHJUb8yNr57OFA5h30S81CfKYmVcH 8UX6Zg4nIg1fV5VjKWZlWA1BNcDXD8z+Ce2BzZoI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Hans de Goede , Sebastian Reichel , Lee Jones Subject: [PATCH 5.15 106/206] leds: led-class: Only Add LED to leds_list when it is fully ready Date: Wed, 4 Feb 2026 15:38:57 +0100 Message-ID: <20260204143902.026512138@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260204143858.193781818@linuxfoundation.org> References: <20260204143858.193781818@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hans de Goede commit d1883cefd31752f0504b94c3bcfa1f6d511d6e87 upstream. Before this change the LED was added to leds_list before led_init_core() gets called adding it the list before led_classdev.set_brightness_work gets initialized. This leaves a window where led_trigger_register() of a LED's default trigger will call led_trigger_set() which calls led_set_brightness() which in turn will end up queueing the *uninitialized* led_classdev.set_brightness_work. This race gets hit by the lenovo-thinkpad-t14s EC driver which registers 2 LEDs with a default trigger provided by snd_ctl_led.ko in quick succession. The first led_classdev_register() causes an async modprobe of snd_ctl_led to run and that async modprobe manages to exactly hit the window where the second LED is on the leds_list without led_init_core() being called for it, resulting in: ------------[ cut here ]------------ WARNING: CPU: 11 PID: 5608 at kernel/workqueue.c:4234 __flush_work+0x344/0x390 Hardware name: LENOVO 21N2S01F0B/21N2S01F0B, BIOS N42ET93W (2.23 ) 09/01/2025 ... Call trace: __flush_work+0x344/0x390 (P) flush_work+0x2c/0x50 led_trigger_set+0x1c8/0x340 led_trigger_register+0x17c/0x1c0 led_trigger_register_simple+0x84/0xe8 snd_ctl_led_init+0x40/0xf88 [snd_ctl_led] do_one_initcall+0x5c/0x318 do_init_module+0x9c/0x2b8 load_module+0x7e0/0x998 Close the race window by moving the adding of the LED to leds_list to after the led_init_core() call. Cc: stable@vger.kernel.org Fixes: d23a22a74fde ("leds: delay led_set_brightness if stopping soft-blink") Signed-off-by: Hans de Goede Reviewed-by: Sebastian Reichel Link: https://patch.msgid.link/20251211163727.366441-1-johannes.goede@oss.qualcomm.com Signed-off-by: Lee Jones Signed-off-by: Greg Kroah-Hartman --- drivers/leds/led-class.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/drivers/leds/led-class.c +++ b/drivers/leds/led-class.c @@ -412,11 +412,6 @@ int led_classdev_register_ext(struct dev #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED led_cdev->brightness_hw_changed = -1; #endif - /* add to the list of leds */ - down_write(&leds_list_lock); - list_add_tail(&led_cdev->node, &leds_list); - up_write(&leds_list_lock); - if (!led_cdev->max_brightness) led_cdev->max_brightness = LED_FULL; @@ -424,6 +419,11 @@ int led_classdev_register_ext(struct dev led_init_core(led_cdev); + /* add to the list of leds */ + down_write(&leds_list_lock); + list_add_tail(&led_cdev->node, &leds_list); + up_write(&leds_list_lock); + #ifdef CONFIG_LEDS_TRIGGERS led_trigger_set_default(led_cdev); #endif