From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 54D93438461; Tue, 28 Jul 2026 12:11:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785240718; cv=none; b=VqzfA73pKjdMlz385DO2/Y2AitG+FS5IKu1gpsF/iVAwvPvqbs1WkWsDEvlcICpZD2ZalbXkykXzKe4NVDeDbcL3LJnK5zMYemCApC07EhNWweitSPPNyLtA73/854kgQL/3SCwzusyG0rBATTbchxXS6Lwety8bJOkR0bacZl4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785240718; c=relaxed/simple; bh=6lBDnfXQfeUOwV/kUF3Gsl2vbQY7z00tTsQAFo4mX7o=; h=Message-ID:Date:MIME-Version:From:Subject:To:Cc:References: In-Reply-To:Content-Type; b=OdEHGHB9pqf62N4LfacDmQ4SxkeiZqG4GLNfLyFeF5QotT597vbsXKOWC1CSV3BLNnPQnAHBNovL+yNK+GPSYZ3dg6dc2d8ybbwl8Xps/zc9AYPYjUqffXOqBypDSaxxKn+DTh58zTAkM/ZgV1xwr2nmcMCgLFDY5UwEV2EANtg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HVZFW/6y; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HVZFW/6y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C1BD01F0155D; Tue, 28 Jul 2026 12:11:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785240713; bh=n99i02Gu7p+ZioXqd7dLXXBNhh5AAfhsFukBthP4AHQ=; h=Date:From:Subject:To:Cc:References:In-Reply-To; b=HVZFW/6ygVur7hpj2Y4Jrsa1fJ33jPFIhdpL719mNJsPahZQ7AjI8d4SPM2qdzFS2 xEndt6xHtRb4kzbTg4SmOyPY+/Tz7ELZRiFn0J4qLDiPfx+jW7H1x8kyUm+mKQf2S/ 4sWEL5Cb1ofPQFXUhOQGUpFDlBCOCOo3BQ2YhXnc9ajzl2kNg+a32IOmGgDCz2/0Nk 7wNjlS9jcCeFchWtQS2d5q5AY5ci1d18O9ka0OfVAOFL69kUyx5OOP8VJDik/GKD1F 78RO55+6y0de2ns87KX25rOkA+r8mQjplqZfFxQamfEtIUlbaKVpGt4JszjHJiwIhg wqevlukUNeTzQ== Message-ID: Date: Tue, 28 Jul 2026 14:11:49 +0200 Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Hans Verkuil Subject: Re: [PATCH v2] media: nuvoton: npcm-video: quiesce VCD IRQ before teardown To: Fan Wu , kwliu@nuvoton.com, kflin@nuvoton.com Cc: hverkuil@kernel.org, mchehab@kernel.org, linux-media@vger.kernel.org, openbmc@lists.ozlabs.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <04a332fc-2025-4a74-ae4d-1d8f30fe20bf@kernel.org> <20260716101539.3129478-1-fanwu01@zju.edu.cn> Content-Language: en-US, nl In-Reply-To: <20260716101539.3129478-1-fanwu01@zju.edu.cn> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Can Nuvoton test this patch? I feel happier if this is given a quick test. Regards, Hans On 16/07/2026 12:15, Fan Wu wrote: > The VCD IRQ is devm-requested, but npcm_video_remove() frees the video > object before devres releases that IRQ. The threaded handler dereferences > video->vcd_regmap before checking VIDEO_STREAMING, so an interrupt in that > interval can access freed memory. > > Request the IRQ with IRQF_NO_AUTOEN. Enable it after starting capture and > setting VIDEO_STREAMING, and disable it first in stop_streaming(). > disable_irq() waits for an in-flight threaded handler to finish, after > which stop_streaming() can mask and reset the VCD without a handler > re-enabling it. > > Use vb2_video_unregister_device() during remove. It releases the vb2 > queue and calls stop_streaming() for an active stream, ensuring that the > IRQ is disabled before the video object is freed. Do not release the queue > separately. > > If streaming is never started, IRQF_NO_AUTOEN keeps the IRQ disabled > until devres releases it. > > This issue was found by an in-house static analysis tool. > > Fixes: 46c15a4ff1f4 ("media: nuvoton: Add driver for NPCM video capture and encoding engine") > Cc: stable@vger.kernel.org > Assisted-by: Codex:gpt-5.6 > Signed-off-by: Fan Wu > --- > Changes since v1: > - Follow Hans Verkuil's suggestion to tie IRQ enablement to the streaming > lifecycle (IRQF_NO_AUTOEN + enable_irq/disable_irq) and to use > vb2_video_unregister_device() for teardown. > > Compile-tested only; I do not have NPCM hardware, so runtime testing by > the Nuvoton maintainers would be appreciated. > --- > drivers/media/platform/nuvoton/npcm-video.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/media/platform/nuvoton/npcm-video.c b/drivers/media/platform/nuvoton/npcm-video.c > index 52505af35c08..c28d9d7edd83 100644 > --- a/drivers/media/platform/nuvoton/npcm-video.c > +++ b/drivers/media/platform/nuvoton/npcm-video.c > @@ -120,6 +120,7 @@ struct npcm_video { > > struct list_head buffers; > struct mutex buffer_lock; /* buffer list lock */ > + int irq; > unsigned long flags; > unsigned int sequence; > > @@ -1486,6 +1487,7 @@ static int npcm_video_start_streaming(struct vb2_queue *q, unsigned int count) > } > > set_bit(VIDEO_STREAMING, &video->flags); > + enable_irq(video->irq); > return 0; > } > > @@ -1494,6 +1496,7 @@ static void npcm_video_stop_streaming(struct vb2_queue *q) > struct npcm_video *video = vb2_get_drv_priv(q); > struct regmap *vcd = video->vcd_regmap; > > + disable_irq(video->irq); > clear_bit(VIDEO_STREAMING, &video->flags); > regmap_write(vcd, VCD_INTE, 0); > regmap_write(vcd, VCD_STAT, VCD_STAT_CLEAR); > @@ -1707,9 +1710,10 @@ static int npcm_video_init(struct npcm_video *video) > dev_err(dev, "Failed to find VCD IRQ\n"); > return -ENODEV; > } > + video->irq = irq; > > rc = devm_request_threaded_irq(dev, irq, NULL, npcm_video_irq, > - IRQF_ONESHOT, DEVICE_NAME, video); > + IRQF_ONESHOT | IRQF_NO_AUTOEN, DEVICE_NAME, video); > if (rc < 0) { > dev_err(dev, "Failed to request IRQ %d\n", irq); > return rc; > @@ -1807,8 +1811,7 @@ static void npcm_video_remove(struct platform_device *pdev) > struct v4l2_device *v4l2_dev = dev_get_drvdata(dev); > struct npcm_video *video = to_npcm_video(v4l2_dev); > > - video_unregister_device(&video->vdev); > - vb2_queue_release(&video->queue); > + vb2_video_unregister_device(&video->vdev); > v4l2_ctrl_handler_free(&video->ctrl_handler); > v4l2_device_unregister(v4l2_dev); > if (video->ece.enable)