From: Yoshihiro Shimoda yoshihiro.shimoda.uh@renesas.com

commit d9f5efade2cfd729138a7cafb46d01044da40f5e upstream

This patch fixes an issue that list_for_each_entry() in usb_dmac_chan_terminate_all() is possible to cause endless loop because this will move own desc to the desc_freed. So, this driver should use list_for_each_entry_safe() instead of list_for_each_entry().

Signed-off-by: Yoshihiro Shimoda yoshihiro.shimoda.uh@renesas.com Signed-off-by: Vinod Koul vinod.koul@intel.com [biju: cherry-pick to 4.4] Signed-off-by: Biju Das biju.das@bp.renesas.com --- Hello Greg,

I have observed a CPU lock condition with USB DMAC driver on koelsch platform. This patch fixes the issue on 4.4 stable. It is reproducible with ethernet(RNDIS/ECM) gadget configuration.

regards, Biju

drivers/dma/sh/usb-dmac.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/sh/usb-dmac.c b/drivers/dma/sh/usb-dmac.c index 56410ea..6682b3e 100644 --- a/drivers/dma/sh/usb-dmac.c +++ b/drivers/dma/sh/usb-dmac.c @@ -448,7 +448,7 @@ usb_dmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, static int usb_dmac_chan_terminate_all(struct dma_chan *chan) { struct usb_dmac_chan *uchan = to_usb_dmac_chan(chan); - struct usb_dmac_desc *desc; + struct usb_dmac_desc *desc, *_desc; unsigned long flags; LIST_HEAD(head); LIST_HEAD(list); @@ -459,7 +459,7 @@ static int usb_dmac_chan_terminate_all(struct dma_chan *chan) if (uchan->desc) uchan->desc = NULL; list_splice_init(&uchan->desc_got, &list); - list_for_each_entry(desc, &list, node) + list_for_each_entry_safe(desc, _desc, &list, node) list_move_tail(&desc->node, &uchan->desc_freed); spin_unlock_irqrestore(&uchan->vc.lock, flags); vchan_dma_desc_free_list(&uchan->vc, &head);