[PATCH 4.4 24/37] dmaengine: usb-dmac: fix endless loop in usb_dmac_chan_terminate_all()

Greg Kroah-Hartman
2018-06-05T17:03:39Z

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>
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- 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 *
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(s
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);