On 5/9/19 4:37 PM, Dave Jiang wrote:
> When ioat_free_chan_resources() gets called, ioat_stop() is called without
> chan->cleanup_lock. ioat_stop modifies IOAT_RUN bit. It needs to be
> protected by cleanup_lock. Also, in the __cleanup() path, if IOAT_RUN is
> cleared, we should not touch the timer again. We observed that the timer
> routine was run after timer was deleted.
>
> Fixes: 3372de5813e ("dmaengine: ioatdma: removal of dma_v3.c and relevant ioat3
> references")
>
> Reported-by: Fan Du <fan.du@xxxxxxxxx>
> Tested-by: Fan Du <fan.du@xxxxxxxxx>
> Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Vinod, can you hold off on this please? There may be more changes. Thanks.
> ---
> drivers/dma/ioat/dma.c | 16 +++++++++-------
> 1 file changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
> index f373a139e0c3..78598ba5c73b 100644
> --- a/drivers/dma/ioat/dma.c
> +++ b/drivers/dma/ioat/dma.c
> @@ -138,11 +138,14 @@ void ioat_stop(struct ioatdma_chan *ioat_chan)
> struct pci_dev *pdev = ioat_dma->pdev;
> int chan_id = chan_num(ioat_chan);
> struct msix_entry *msix;
> + unsigned long flags;
>
> - /* 1/ stop irq from firing tasklets
> - * 2/ stop the tasklet from re-arming irqs
> - */
> + spin_lock_irqsave(&ioat_chan->cleanup_lock, flags);
> clear_bit(IOAT_RUN, &ioat_chan->state);
> + spin_unlock_irqrestore(&ioat_chan->cleanup_lock, flags);
> +
> + /* flush inflight timers */
> + del_timer_sync(&ioat_chan->timer);
>
> /* flush inflight interrupts */
> switch (ioat_dma->irq_mode) {
> @@ -158,9 +161,6 @@ void ioat_stop(struct ioatdma_chan *ioat_chan)
> break;
> }
>
> - /* flush inflight timers */
> - del_timer_sync(&ioat_chan->timer);
> -
> /* flush inflight tasklet runs */
> tasklet_kill(&ioat_chan->cleanup_task);
>
> @@ -652,7 +652,9 @@ static void __cleanup(struct ioatdma_chan *ioat_chan, dma_addr_t phys_complete)
> if (active - i == 0) {
> dev_dbg(to_dev(ioat_chan), "%s: cancel completion timeout\n",
> __func__);
> - mod_timer(&ioat_chan->timer, jiffies + IDLE_TIMEOUT);
> +
> + if (test_bit(IOAT_RUN, &ioat_chan->state))
> + mod_timer(&ioat_chan->timer, jiffies + IDLE_TIMEOUT);
> }
>
> /* microsecond delay by sysfs variable per pending descriptor */
>
