Messages in this thread Patch in this message | | | From | Will Deacon <> | Subject | [PATCH] dma: pl330: ensure DMA descriptors are zero-initialised | Date | Fri, 29 Nov 2013 11:50:28 +0000 |
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I see the following splat with 3.13-rc1 when attempting to perform DMA:
[ 253.004516] Alignment trap: not handling instruction e1902f9f at [<c0204b40>] [ 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 : [<c0204b44>] lr : [<c0207478>] 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: Jassi Brar <jaswinder.singh@linaro.org> Cc: Vinod Koul <vinod.koul@intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Will Deacon <will.deacon@arm.com> --- drivers/dma/pl330.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index 98641eaca080..79e52a94f054 100644 --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -2492,14 +2492,8 @@ 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; desc->req.xfer_cb = dma_pl330_rqcb; desc->txd.tx_submit = pl330_tx_submit; @@ -2517,7 +2511,7 @@ 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 = kzalloc(count * sizeof(*desc), flg); if (!desc) return 0; -- 1.8.2.2
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