Messages in this thread | | | Subject | Re: [PATCH 4.9 038/109] dmaengine: stm32-dma: Fix null pointer dereference in stm32_dma_tx_status | From | Ludovic BARRE <> | Date | Thu, 7 Dec 2017 14:18:51 +0100 |
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with Pierre Yves mail it's better ;-)
On 12/07/2017 02:04 PM, Ludovic BARRE wrote: > add Pierre-yves Mordret > > acked-by: Ludovic BARRE <ludovic.barre@st.com> > > On 12/07/2017 01:56 PM, Greg Kroah-Hartman wrote: >> 4.9-stable review patch. If anyone has any objections, please let me >> know. >> >> ------------------ >> >> From: M'boumba Cedric Madianga <cedric.madianga@gmail.com> >> >> >> [ Upstream commit 57b5a32135c813f2ab669039fb4ec16b30cb3305 ] >> >> chan->desc is always set to NULL when a DMA transfer is complete. >> As a DMA transfer could be complete during the call of >> stm32_dma_tx_status, >> we need to be sure that chan->desc is not NULL before using this variable >> to avoid a null pointer deference issue. >> >> Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com> >> Reviewed-by: Ludovic BARRE <ludovic.barre@st.com> >> Signed-off-by: Vinod Koul <vinod.koul@intel.com> >> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> >> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> >> --- >> drivers/dma/stm32-dma.c | 10 +++------- >> 1 file changed, 3 insertions(+), 7 deletions(-) >> >> --- a/drivers/dma/stm32-dma.c >> +++ b/drivers/dma/stm32-dma.c >> @@ -884,7 +884,7 @@ static enum dma_status stm32_dma_tx_stat >> struct virt_dma_desc *vdesc; >> enum dma_status status; >> unsigned long flags; >> - u32 residue; >> + u32 residue = 0; >> status = dma_cookie_status(c, cookie, state); >> if ((status == DMA_COMPLETE) || (!state)) >> @@ -892,16 +892,12 @@ static enum dma_status stm32_dma_tx_stat >> spin_lock_irqsave(&chan->vchan.lock, flags); >> vdesc = vchan_find_desc(&chan->vchan, cookie); >> - if (cookie == chan->desc->vdesc.tx.cookie) { >> + if (chan->desc && cookie == chan->desc->vdesc.tx.cookie) >> residue = stm32_dma_desc_residue(chan, chan->desc, >> chan->next_sg); >> - } else if (vdesc) { >> + else if (vdesc) >> residue = stm32_dma_desc_residue(chan, >> to_stm32_dma_desc(vdesc), 0); >> - } else { >> - residue = 0; >> - } >> - >> dma_set_residue(state, residue); >> spin_unlock_irqrestore(&chan->vchan.lock, flags); >> >>
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