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 D0DD743CEF5; Tue, 21 Jul 2026 22:02:51 +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=1784671372; cv=none; b=MY9spOtyrf9m7xqODgUqlwSWqkHHkkrPRiQzo0HSKBuGxnOOTV9ayV0nvbKPJAPbmLFXOo3iIwyPERpEn/+CAbFKSTvo1CBv5ApV5U+Xe1JrIZlNOhnde2VlzhddsYrihIvd2hx9NktlQhFhcaZj2H1dAMENwFaNtY+t/QfhclE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784671372; c=relaxed/simple; bh=YKCu+2Q4R4DhsG+ylBUvRISsbwHX3mkapS+Itgsifnc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nrF3DvAuiuVoZI3T0blD4ehmIe/xJeJRb/33/7IJIzpd0zukvSrzgAV2Ys7oYgyKFKfJWoV1TMqEvNo0IUUOd01V+9FNe0Fl+gBWYFkVA9Nhg8UYn5r3rxRpqzrY4sVq11uTQjyB66C5hTNbqyOEiRtSa728Ljingy2+/ggurfA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Ourq5SAI; 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="Ourq5SAI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2AE451F000E9; Tue, 21 Jul 2026 22:02:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784671371; bh=Kk9bjKayME+VFz6+vyhE4M7dkTbNEo+xd20iLjNZMYo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Ourq5SAII7/yM/z7uKJ0QtFtOR31iNGoKw11SxH3KqaXJ6hHXWdDzqYojI0YvF7pk mNQUyoZi/hUpth17vZLwbHweHS5n3DtlGfcDRL0hDUDBj+r911r/h7P3qj4/W9X1fd BDX5MEX/aDSOno+fh4wTKlV7Zr5I+wZyXZ+BSPh8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mikhail Gavrilov , Vivek Kasireddy Subject: [PATCH 5.15 178/843] udmabuf: fix DMA direction mismatch in release_udmabuf() Date: Tue, 21 Jul 2026 17:16:53 +0200 Message-ID: <20260721152410.020103390@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152405.946368001@linuxfoundation.org> References: <20260721152405.946368001@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 5.15-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 @@ -25,6 +25,7 @@ struct udmabuf { pgoff_t pagecount; struct page **pages; struct sg_table *sg; + enum dma_data_direction sg_dir; struct miscdevice *device; }; @@ -111,7 +112,7 @@ 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]); @@ -131,6 +132,8 @@ 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);