From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753403Ab3LBSCQ (ORCPT ); Mon, 2 Dec 2013 13:02:16 -0500 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:56387 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753142Ab3LBSCK (ORCPT ); Mon, 2 Dec 2013 13:02:10 -0500 From: Will Deacon To: dmaengine@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Will Deacon , Andriy Shevchenko , Vinod Koul , Dan Williams Subject: [PATCH v2] dma: pl330: ensure DMA descriptors are zero-initialised Date: Mon, 2 Dec 2013 18:01:30 +0000 Message-Id: <1386007290-13987-1-git-send-email-will.deacon@arm.com> X-Mailer: git-send-email 1.8.2.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I see the following splat with 3.13-rc1 when attempting to perform DMA: [ 253.004516] Alignment trap: not handling instruction e1902f9f at [] [ 253.004583] Unhandled fault: alignment exception (0x221) at 0xdfdfdfd7 [ 253.004646] Internal error: : 221 [#1] PREEMPT SMP ARM [ 253.004691] Modules linked in: dmatest(+) [last unloaded: dmatest] [ 253.004798] CPU: 0 PID: 671 Comm: kthreadd Not tainted 3.13.0-rc1+ #2 [ 253.004864] task: df9b0900 ti: df03e000 task.ti: df03e000 [ 253.004937] PC is at dmaengine_unmap_put+0x14/0x34 [ 253.005010] LR is at pl330_tasklet+0x3c8/0x550 [ 253.005087] pc : [] lr : [] psr: a00e0193 [ 253.005087] sp : df03fe48 ip : 00000000 fp : df03bf18 [ 253.005178] r10: bf00e108 r9 : 00000001 r8 : 00000000 [ 253.005245] r7 : df837040 r6 : dfb41800 r5 : df837048 r4 : df837000 [ 253.005316] r3 : dfdfdfcf r2 : dfb41f80 r1 : df837048 r0 : dfdfdfd7 [ 253.005384] Flags: NzCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel [ 253.005459] Control: 30c5387d Table: 9fb9ba80 DAC: fffffffd [ 253.005520] Process kthreadd (pid: 671, stack limit = 0xdf03e248) This is due to desc->txd.unmap containing garbage (uninitialised memory). Rather than add another dummy initialisation to _init_desc, instead ensure that the descriptors are zero-initialised during allocation and remove the dummy, per-field initialisation. Cc: Andriy Shevchenko Cc: Vinod Koul Cc: Dan Williams Acked-by: Jassi Brar Signed-off-by: Will Deacon --- drivers/dma/pl330.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index 98641eaca080..769f865b71db 100644 --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -2492,12 +2492,9 @@ static dma_cookie_t pl330_tx_submit(struct dma_async_tx_descriptor *tx) static inline void _init_desc(struct dma_pl330_desc *desc) { - desc->pchan = NULL; desc->req.x = &desc->px; desc->req.token = desc; desc->rqcfg.swap = SWAP_NO; - desc->rqcfg.privileged = 0; - desc->rqcfg.insnaccess = 0; desc->rqcfg.scctl = SCCTRL0; desc->rqcfg.dcctl = DCCTRL0; desc->req.cfg = &desc->rqcfg; @@ -2517,7 +2514,7 @@ static int add_desc(struct dma_pl330_dmac *pdmac, gfp_t flg, int count) if (!pdmac) return 0; - desc = kmalloc(count * sizeof(*desc), flg); + desc = kcalloc(count, sizeof(*desc), flg); if (!desc) return 0; -- 1.8.2.2