From nobody Sun Sep 14 14:29:55 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8B66C05027 for ; Fri, 20 Jan 2023 10:06:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230501AbjATKGw (ORCPT ); Fri, 20 Jan 2023 05:06:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53154 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230303AbjATKGu (ORCPT ); Fri, 20 Jan 2023 05:06:50 -0500 Received: from esa.microchip.iphmx.com (esa.microchip.iphmx.com [68.232.154.123]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27D89A258E; Fri, 20 Jan 2023 02:06:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1674209208; x=1705745208; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=s8RVOfsWfXmS7vuK9YlhjZHo4/cTdmhqpji15rJG740=; b=ERBYlyKn1jXKVcB9EXZ0j+1fBhQ9idCwTWNM+Zmnr60LQ0PwOKxeyb7v 0/nY0mYXh62sYuOl6Em/xQICSApgDL+tTbS0Uuo5KZNj2VzZRFp7xk/Hh 8N2YilcB1cusE3+etvWA22VB+7GvTrsQYX8UIv5Q3I+J0hxhS5ouJVF+2 U2rO0bWIRVUThNxem5bgMlr2ISin4TY6wJmF4j9P1P/l02AfUNk3eauQ5 2NkBYpAydNspQriK1JKNeGgwPx/Ya88NhWDmurApNVFSjwi83Q5dtMapD Z/vkEpaHh0c7jwGi6MmArAw9GzSdEBRvmaoZQVArPyZrOa+N4rw8dkP1P w==; X-IronPort-AV: E=Sophos;i="5.97,231,1669100400"; d="scan'208";a="196675868" Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa2.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 20 Jan 2023 03:06:47 -0700 Received: from chn-vm-ex03.mchp-main.com (10.10.85.151) by chn-vm-ex02.mchp-main.com (10.10.85.144) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.16; Fri, 20 Jan 2023 03:06:47 -0700 Received: from microchip1-OptiPlex-9020.microchip.com (10.10.115.15) by chn-vm-ex03.mchp-main.com (10.10.85.151) with Microsoft SMTP Server id 15.1.2507.16 via Frontend Transport; Fri, 20 Jan 2023 03:06:44 -0700 From: shravan kumar To: , , , CC: , , , Subject: [PATCH v1] dmaengine: sf-pdma: pdma_desc memory leak fix Date: Fri, 20 Jan 2023 15:36:23 +0530 Message-ID: <20230120100623.3530634-1-shravan.chippa@microchip.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Shravan Chippa Commit b2cc5c465c2c ("dmaengine: sf-pdma: Add multithread support for a DMA channel") changed sf_pdma_prep_dma_memcpy() to unconditionally allocate a new sf_pdma_desc each time it is called. The driver previously recycled descs, by checking the in_use flag, only allocating additional descs if the existing one was in use. This logic was removed in commit b2cc5c465c2c ("dmaengine: sf-pdma: Add multithread support for a DMA channel"), but sf_pdma_free_desc() was not changed to handle the new behaviour. As a result, each time sf_pdma_prep_dma_memcpy() is called, the previous descriptor is leaked, over time leading to memory starvation: unreferenced object 0xffffffe008447300 (size 192): comm "irq/39-mchp_dsc", pid 343, jiffies 4294906910 (age 981.200s) hex dump (first 32 bytes): 00 00 00 ff 00 00 00 00 b8 c1 00 00 00 00 00 00 ................ 00 00 70 08 10 00 00 00 00 00 00 c0 00 00 00 00 ..p............. backtrace: [<00000000064a04f4>] kmemleak_alloc+0x1e/0x28 [<00000000018927a7>] kmem_cache_alloc+0x11e/0x178 [<000000002aea8d16>] sf_pdma_prep_dma_memcpy+0x40/0x112 Add the missing kfree() to sf_pdma_free_desc(), and remove the redundant in_use flag. Fixes: b2cc5c465c2c ("dmaengine: sf-pdma: Add multithread support for a DMA= channel") Signed-off-by: Shravan Chippa Reviewed-by: Conor Dooley --- drivers/dma/sf-pdma/sf-pdma.c | 3 +-- drivers/dma/sf-pdma/sf-pdma.h | 1 - 2 files changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/dma/sf-pdma/sf-pdma.c b/drivers/dma/sf-pdma/sf-pdma.c index 6b524eb6bcf3..e578ad556949 100644 --- a/drivers/dma/sf-pdma/sf-pdma.c +++ b/drivers/dma/sf-pdma/sf-pdma.c @@ -96,7 +96,6 @@ sf_pdma_prep_dma_memcpy(struct dma_chan *dchan, dma_addr_= t dest, dma_addr_t src, if (!desc) return NULL; =20 - desc->in_use =3D true; desc->dirn =3D DMA_MEM_TO_MEM; desc->async_tx =3D vchan_tx_prep(&chan->vchan, &desc->vdesc, flags); =20 @@ -290,7 +289,7 @@ static void sf_pdma_free_desc(struct virt_dma_desc *vde= sc) struct sf_pdma_desc *desc; =20 desc =3D to_sf_pdma_desc(vdesc); - desc->in_use =3D false; + kfree(desc); } =20 static void sf_pdma_donebh_tasklet(struct tasklet_struct *t) diff --git a/drivers/dma/sf-pdma/sf-pdma.h b/drivers/dma/sf-pdma/sf-pdma.h index dcb3687bd5da..5c398a83b491 100644 --- a/drivers/dma/sf-pdma/sf-pdma.h +++ b/drivers/dma/sf-pdma/sf-pdma.h @@ -78,7 +78,6 @@ struct sf_pdma_desc { u64 src_addr; struct virt_dma_desc vdesc; struct sf_pdma_chan *chan; - bool in_use; enum dma_transfer_direction dirn; struct dma_async_tx_descriptor *async_tx; }; --=20 2.34.1