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 3003C2D660E; Wed, 28 Jan 2026 15:36:31 +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=1769614592; cv=none; b=kFazwtU0u3SMy/dE9bmgwl2f+nBBEBu9RZqPkW9KnbGAswa8ZpfYJhM3+sU8qiXfJlnvim2JxGxtKuoWh7tLVEi8aunwLIhF/58x99j+Vy5Kvx4mnDlP6xGXf0WUxnWS+WvYHsCF6mFTcemFtb71NzbwO210dqewxIkDvhLOKzw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769614592; c=relaxed/simple; bh=1vO8J71t8Cxi1hlKVIiZB/YTbfzN2fsd1WR4lbqgiV8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UKi3/Rj/YXJiBhgans1xsZPieM2tGQZbu/cHPU3IBqkHtQwSrikA7hZHPUnqvXUqy7DPt1gyTi+UWkB20eXS11B2mgbUR/RWrZPbzXcPy0DSmFIRkwrWX1mN3oXRDwi+pxsjq7YStvO2xEZAv9OqF4oycq4w16UaGgjRsbxIR1c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mCK4g3eb; 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="mCK4g3eb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 619A6C4CEF1; Wed, 28 Jan 2026 15:36:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1769614591; bh=1vO8J71t8Cxi1hlKVIiZB/YTbfzN2fsd1WR4lbqgiV8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mCK4g3eb6jeOH4vBTiAkBQNjBqQetqc930UQ2TwS1P84GTg4C3g1KzPlshFaQmsRf njJBE4GxastwXxZcP4GVVycMDSTZsvxGufQOyjml0emb9f3B3UpDUBKWBXje9ET6EN FPF6Rz4I4TcTTlnLpLi0mu0py32LD1QCxMFH8QRY= 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 6.6 184/254] leds: led-class: Only Add LED to leds_list when it is fully ready Date: Wed, 28 Jan 2026 16:22:40 +0100 Message-ID: <20260128145351.424389092@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260128145344.698118637@linuxfoundation.org> References: <20260128145344.698118637@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 6.6-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 @@ -546,11 +546,6 @@ 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; @@ -558,6 +553,11 @@ 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