From nobody Sat Jul 25 20:08:11 2026 Received: from mailgw.kylinos.cn (mailgw.kylinos.cn [124.126.103.232]) (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 AD35B13D886; Tue, 14 Jul 2026 03:30:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=124.126.103.232 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783999860; cv=none; b=h49EzvHtUo4j1W57/eK22/wpmJmFoNX2X+wI8ZHhUY5ijyU5JjyBH6Mn4W3vOr0PS6WKKGjZ01BhrXIfHj9rlqJo87csNBW7Tx8d9BCaij0D76YKO1FwW3ejuNaaUC39FQyCA+Xb2Ko++CgRPX+eymZcA0zc8xCtSWG8hCUqBaM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783999860; c=relaxed/simple; bh=6TesKtS8aX+cKqBJvBoHE55K5LdLPD24p+gAmYAX+ks=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version:Content-Type; b=M3NUTWQuni9Lw6wKfgwXjb7q2MqOncMCX79yg7TUN3rFtNkMd9qc72HIjsXil3lkk1FqPiiDa0wgS6vQysFitdt8uWGU4DI+wwgg/nd8En4Oh0P+ilaAr0dyoz/I/oQieGXcrqkDPSQ7AYHRIlvMsFciyh1KSEFPSmfMkGpK694= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kylinos.cn; spf=pass smtp.mailfrom=kylinos.cn; arc=none smtp.client-ip=124.126.103.232 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kylinos.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kylinos.cn X-UUID: 68fc48247f3411f1aa26b74ffac11d73-20260714 X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.3.12,REQID:49dc99e2-bc32-4451-92b9-6f185baa9866,IP:0,U RL:0,TC:0,Content:-25,EDM:0,RT:0,SF:0,FILE:0,BULK:0,RULE:Release_Ham,ACTIO N:release,TS:-25 X-CID-META: VersionHash:e7bac3a,CLOUDID:d085e429446b2b9a9044084871bdeac6,BulkI D:nil,BulkQuantity:0,Recheck:0,SF:102|850|865|898,TC:nil,Content:0|15|50,E DM:-3,IP:nil,URL:0,File:nil,RT:nil,Bulk:nil,QS:nil,BEC:nil,COL:0,OSI:0,OSA :0,AV:0,LES:1,SPR:NO,DKR:0,DKP:0,BRR:0,BRE:0,ARC:0 X-CID-BVR: 2,SSN|SDN X-CID-BAS: 2,SSN|SDN,0,_ X-CID-FACTOR: TF_CID_SPAM_SNR X-CID-RHF: D41D8CD98F00B204E9800998ECF8427E X-UUID: 68fc48247f3411f1aa26b74ffac11d73-20260714 X-User: zenghongling@kylinos.cn Received: from localhost.localdomain [(10.44.16.150)] by mailgw.kylinos.cn (envelope-from ) (Generic MTA with TLSv1.3 TLS_AES_256_GCM_SHA384 256/256) with ESMTP id 2049219937; Tue, 14 Jul 2026 11:30:50 +0800 From: Hongling Zeng To: vkoul@kernel.org, Frank.Li@kernel.org, arnd@arndb.de, jonas.jensen@gmail.com Cc: dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, zhongling0719@126.com, Hongling Zeng , stable@vger.kernel.org Subject: [PATCH v2] dmaengine: moxart: Fix use-after-free by proper tasklet cleanup Date: Tue, 14 Jul 2026 11:30:46 +0800 Message-Id: <20260714033046.673677-1-zenghongling@kylinos.cn> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The moxart DMA driver has a use-after-free vulnerability: - vchan_init() creates tasklets that access moxart_chan memory - Neither probe error paths nor remove() call tasklet_kill() - devm_free_irq() only waits for IRQ handler, NOT tasklets - mdc is devm-managed and freed after probe/remove - Running tasklets accessing freed memory =E2=86=92 Use-After-Free! Fix by adding moxart_dma_free_channels() helper that calls tasklet_kill() for each channel, and ensuring proper teardown order: In remove(): - devm_free_irq() FIRST to stop the IRQ handler (implies synchronize_irq(), preventing new tasklets from being scheduled) - moxart_dma_free_channels() to kill already-scheduled tasklets - Then of_dma_controller_free() and dma_async_device_unregister() to safely unregister the device In probe error path: - moxart_dma_free_channels() to kill tasklets created by vchan_init() - devm_request_irq() is automatically released by devres, so no explicit devm_free_irq() is needed Fixes: 5f9e685a0d46 ("dmaengine: Add MOXA ART DMA engine driver") Cc: stable@vger.kernel.org Signed-off-by: Hongling Zeng --- Change in v2: - The DMA core's dma_async_device_unregister() handles all channel cleanup including sysfs entries, IDA tags, and per-cpu memory, so we don't call list_del() on the channel nodes. --- drivers/dma/moxart-dma.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) diff --git a/drivers/dma/moxart-dma.c b/drivers/dma/moxart-dma.c index 442f5aa16031..a2481960e870 100644 --- a/drivers/dma/moxart-dma.c +++ b/drivers/dma/moxart-dma.c @@ -553,6 +553,21 @@ static irqreturn_t moxart_dma_interrupt(int irq, void = *devid) return IRQ_HANDLED; } =20 +static void moxart_dma_free_channels(struct moxart_dmadev *mdc) +{ + struct moxart_chan *ch; + int i; + + for (i =3D 0; i < APB_DMA_MAX_CHANNEL; i++) { + ch =3D &mdc->slave_chans[i]; + /* + * Wait for any scheduled tasklet to complete before channel + * memory is freed by devres. + */ + tasklet_kill(&ch->vc.task); + } +} + static int moxart_probe(struct platform_device *pdev) { struct device *dev =3D &pdev->dev; @@ -609,19 +624,23 @@ static int moxart_probe(struct platform_device *pdev) ret =3D dma_async_device_register(&mdc->dma_slave); if (ret) { dev_err(dev, "dma_async_device_register failed\n"); - return ret; + goto err_dma_register; } =20 ret =3D of_dma_controller_register(node, moxart_of_xlate, mdc); if (ret) { dev_err(dev, "of_dma_controller_register failed\n"); dma_async_device_unregister(&mdc->dma_slave); - return ret; + goto err_dma_register; } =20 dev_dbg(dev, "%s: IRQ=3D%u\n", __func__, irq); =20 return 0; + +err_dma_register: + moxart_dma_free_channels(mdc); + return ret; } =20 static void moxart_remove(struct platform_device *pdev) @@ -630,10 +649,12 @@ static void moxart_remove(struct platform_device *pde= v) =20 devm_free_irq(&pdev->dev, m->irq, m); =20 - dma_async_device_unregister(&m->dma_slave); + moxart_dma_free_channels(m); =20 if (pdev->dev.of_node) of_dma_controller_free(pdev->dev.of_node); + + dma_async_device_unregister(&m->dma_slave); } =20 static const struct of_device_id moxart_dma_match[] =3D { --=20 2.25.1