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 10BBE47143C; Tue, 21 Jul 2026 20:23:50 +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=1784665431; cv=none; b=BF2rjlooYUbt3CnI0GsdRu32wHI/WqbQ1Yi0LCsTXgg4D5Es3SyZL8RFmqqIfJYOqoosPVo1ny6OqZfli32sGK92AMlLj9iZN8/blbkMjByw9qiRLDNOCj902jJVs7saBHRLn76s+Ut5w7mlD4iOghKZXGJycv6B6ox7kKoZ4jM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784665431; c=relaxed/simple; bh=aLbuMZXVR7aO7IQSEWfaUNoMLFvNQ+FB/uFGZPysTaI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VK+ht64z69BkZcgFqovUQOft7+h7DKNVR9Bf2BXbCVD7yp66Weq2IlbJDU9Oknx/7rVQ8TbDuSF8iwxISk9O4bqHP6RYQi6UubohI/yo7A6+EkeoyTjGUddPYQpvRyKn7/t9LU2vdy831rlkZSr05h8hyzoq2zX4MVgOKaUjyYg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Be+BagDR; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Be+BagDR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6EF031F000E9; Tue, 21 Jul 2026 20:23:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784665429; bh=N/NopVovgaTD11nPZfShR4odDbVqb7qa/o1AN3fyAkQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Be+BagDRGoe2eQfbjVgN1e3sspp9skEhuX/bQQtzuLOhw70YlacS3p4ImErA7PvU7 vgysPpr1/S82OLu6NzUg+BJgYwW0ROPxjf5AZSZDiuEdcsXVGmyO9Bcw53EmqvlJ3z hL63ttXaiEp/8MhOx/KIgQlbHOROR1AB6vmi+TPY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mikhail Gavrilov , Vivek Kasireddy Subject: [PATCH 6.6 0301/1266] udmabuf: fix DMA direction mismatch in release_udmabuf() Date: Tue, 21 Jul 2026 17:12:18 +0200 Message-ID: <20260721152448.562855875@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152441.786066624@linuxfoundation.org> References: <20260721152441.786066624@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev 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: Mikhail Gavrilov commit fb7b1a0ab25a6077d26cb3829e31743972d4f31d upstream. begin_cpu_udmabuf() maps the sg_table with the caller-provided direction (e.g., DMA_TO_DEVICE for a write-only sync), and caches it in ubuf->sg for reuse. However, release_udmabuf() always unmaps this sg_table with a hardcoded DMA_BIDIRECTIONAL, regardless of the direction that was originally used for the mapping. With CONFIG_DMA_API_DEBUG=y this produces: DMA-API: misc udmabuf: device driver frees DMA memory with different direction [device address=0x000000044a123000] [size=4096 bytes] [mapped with DMA_TO_DEVICE] [unmapped with DMA_BIDIRECTIONAL] The issue was found during video playback when GStreamer performed a write-only DMA_BUF_IOCTL_SYNC on a udmabuf. It can be reproduced with CONFIG_DMA_API_DEBUG=y by creating a udmabuf from a memfd, performing a write-only sync (DMA_BUF_SYNC_WRITE without DMA_BUF_SYNC_READ), and closing the file descriptor. Fix this by storing the DMA direction used when the sg_table is first created in begin_cpu_udmabuf(), and passing that same direction to put_sg_table() in release_udmabuf(). Fixes: 284562e1f348 ("udmabuf: implement begin_cpu_access/end_cpu_access hooks") Cc: stable@vger.kernel.org Signed-off-by: Mikhail Gavrilov Reviewed-by: Vivek Kasireddy Signed-off-by: Vivek Kasireddy Link: https://patch.msgid.link/20260314232722.15555-1-mikhail.v.gavrilov@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/dma-buf/udmabuf.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -27,6 +27,7 @@ struct udmabuf { pgoff_t pagecount; struct page **pages; struct sg_table *sg; + enum dma_data_direction sg_dir; struct miscdevice *device; }; @@ -139,7 +140,7 @@ static void release_udmabuf(struct dma_b pgoff_t pg; if (ubuf->sg) - put_sg_table(dev, ubuf->sg, DMA_BIDIRECTIONAL); + put_sg_table(dev, ubuf->sg, ubuf->sg_dir); for (pg = 0; pg < ubuf->pagecount; pg++) put_page(ubuf->pages[pg]); @@ -159,6 +160,8 @@ static int begin_cpu_udmabuf(struct dma_ if (IS_ERR(ubuf->sg)) { ret = PTR_ERR(ubuf->sg); ubuf->sg = NULL; + } else { + ubuf->sg_dir = direction; } } else { dma_sync_sgtable_for_cpu(dev, ubuf->sg, direction);