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 D564121CA11; Tue, 11 Feb 2025 13:34:33 +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=1739280874; cv=none; b=OsnebFXjgd7UFXnLM+/clJ0DOnpjGMfsQcF34cGvuWqolUCILScjKbSowUsTHVx6W9CLd6HJrau0kat+P1RAX+e/WFLuk69z3EgS5AoxksFYw/22BV/THOaNXlJErqnHRn/GTOCpk4ff3O8Q6khNRxn7fq9/ilyhiepQ7X4VBXU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739280874; c=relaxed/simple; bh=6uFr4TEEuOuodhf3oFnR391DwkPMiTazsKy65s3UKdg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VOQfvAEdK/RlU1Vhaa7BrKieJp5Nw2J5XdKh7rvOzPFpLRehTtkJ30cNwMULbnmzkag/7CXDxNDKE5k3Kv5IgOgFV1k91usmKaIyYGMkUu8e3j7777QyrQuGBdyn5ust+Sf2tpSpjArZ0d9l3wM1AG6aqF79N5aYzF9HP2xCkLA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oBYjomBb; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oBYjomBb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E5FE0C4CEDD; Tue, 11 Feb 2025 13:34:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739280873; bh=6uFr4TEEuOuodhf3oFnR391DwkPMiTazsKy65s3UKdg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oBYjomBbc5daO3C/6Ela/8aPN44Sx/D8p4jjCnOlCOUuU5qg98Tk0kFb9HaImmJ0Q uSjWRewYrTBG5gNkoBqhpgJK5fG+jOaAD1wKbHa2OSumUSUNKCmrnntvui8IZ71DwL c5v3IkvaODh9d7vcb2sTVPb7TdnwQgaWB1kNH4jo5i5DJA4dQmv28uYHGz+6hcGt0a ZJ46xYHB/7u3LbEjIGT2Lm08L6rGRhzyJTYrbsAVGf/7zlJBO9gxBMcLTKr6E0vPib ajVBL4U1wSHzHCApa6zCzMPoH4gUWROuq1YVpg5RxDJlNPeE4ar6LwKsJ5AlU/BUbI J1s86WpuNqFQg== Date: Tue, 11 Feb 2025 13:34:29 +0000 From: Lee Jones To: Manuel Fombuena Cc: pavel@ucw.cz, corbet@lwn.net, linux-leds@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RESEND 1/5] leds: leds-st1202: fix NULL pointer access on race condition Message-ID: <20250211133429.GQ1868108@google.com> References: Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Sat, 01 Feb 2025, Manuel Fombuena wrote: > st1202_dt_init() calls devm_led_classdev_register_ext() before the > internal data structures are properly setup, so the leds become visible Always "LEDs". > to user space while being partially initialized, leading to a window > where trying to access them causes a NULL pointer access. > > This change moves devm_led_classdev_register_ext() to the last thing to > happen during initialization to eliminate it. > > Signed-off-by: Manuel Fombuena > --- > drivers/leds/leds-st1202.c | 21 ++++++++++----------- > 1 file changed, 10 insertions(+), 11 deletions(-) > > diff --git a/drivers/leds/leds-st1202.c b/drivers/leds/leds-st1202.c > index b691c4886993..e894b3f9a0f4 100644 > --- a/drivers/leds/leds-st1202.c > +++ b/drivers/leds/leds-st1202.c > @@ -261,8 +261,6 @@ static int st1202_dt_init(struct st1202_chip *chip) > int err, reg; > > for_each_available_child_of_node_scoped(dev_of_node(dev), child) { > - struct led_init_data init_data = {}; > - > err = of_property_read_u32(child, "reg", ®); > if (err) > return dev_err_probe(dev, err, "Invalid register\n"); > @@ -276,15 +274,6 @@ static int st1202_dt_init(struct st1202_chip *chip) > led->led_cdev.pattern_set = st1202_led_pattern_set; > led->led_cdev.pattern_clear = st1202_led_pattern_clear; > led->led_cdev.default_trigger = "pattern"; > - > - init_data.fwnode = led->fwnode; > - init_data.devicename = "st1202"; > - init_data.default_label = ":"; > - > - err = devm_led_classdev_register_ext(dev, &led->led_cdev, &init_data); > - if (err < 0) > - return dev_err_probe(dev, err, "Failed to register LED class device\n"); > - > led->led_cdev.brightness_set = st1202_brightness_set; > led->led_cdev.brightness_get = st1202_brightness_get; > } > @@ -368,6 +357,7 @@ static int st1202_probe(struct i2c_client *client) > return ret; > > for (int i = 0; i < ST1202_MAX_LEDS; i++) { > + struct led_init_data init_data = {}; > led = &chip->leds[i]; > led->chip = chip; > led->led_num = i; > @@ -384,6 +374,15 @@ static int st1202_probe(struct i2c_client *client) > if (ret < 0) > return dev_err_probe(&client->dev, ret, > "Failed to clear LED pattern\n"); > + > + init_data.fwnode = led->fwnode; > + init_data.devicename = "st1202"; > + init_data.default_label = ":"; > + > + ret = devm_led_classdev_register_ext(&client->dev, &led->led_cdev, &init_data); > + if (ret < 0) > + return dev_err_probe(&client->dev, ret, > + "Failed to register LED class device\n"); > } > > return 0; > -- > 2.48.1 > -- Lee Jones [李琼斯]