xhci_free_tt_info() may access the invalid memory when it removes the
last entry but the list is not empty. Then tt_next reaches to the
list head but it still tries to check the tt_info of that entry.
This patch fixes the bug and cleans up the messy code by rewriting
with a simple list_for_each_entry_safe().
Cc: <stable@xxxxxxxxxxxxxxx>
Reviewed-by: Oliver Neukum <oneukum@xxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
drivers/usb/host/xhci-mem.c | 38 +++++++++-----------------------------
1 file changed, 9 insertions(+), 29 deletions(-)
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index ec4338e..4e1da7f 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -793,10 +793,9 @@ static void xhci_free_tt_info(struct xhci_hcd *xhci,
struct xhci_virt_device *virt_dev,
int slot_id)
{
- struct list_head *tt;
struct list_head *tt_list_head;
- struct list_head *tt_next;
- struct xhci_tt_bw_info *tt_info;
+ struct xhci_tt_bw_info *tt_info, *next;
+ bool slot_found = false;
/* If the device never made it past the Set Address stage,
* it may not have the real_port set correctly.
@@ -808,34 +807,15 @@ static void xhci_free_tt_info(struct xhci_hcd *xhci,
}
tt_list_head = &(xhci->rh_bw[virt_dev->real_port - 1].tts);
- if (list_empty(tt_list_head))
- return;
-
- list_for_each(tt, tt_list_head) {
- tt_info = list_entry(tt, struct xhci_tt_bw_info, tt_list);
- if (tt_info->slot_id == slot_id)
+ list_for_each_entry_safe(tt_info, next, tt_list_head, tt_list) {
+ /* Multi-TT hubs will have more than one entry */
+ if (tt_info->slot_id == slot_id) {
+ slot_found = true;
+ list_del(&tt_info->tt_list);
+ kfree(tt_info);
+ } else if (slot_found)
break;
}
- /* Cautionary measure in case the hub was disconnected before we
- * stored the TT information.
- */
- if (tt_info->slot_id != slot_id)
- return;
-
- tt_next = tt->next;
- tt_info = list_entry(tt, struct xhci_tt_bw_info,
- tt_list);
- /* Multi-TT hubs will have more than one entry */
- do {
- list_del(tt);
- kfree(tt_info);
- tt = tt_next;
- if (list_empty(tt_list_head))
- break;
- tt_next = tt->next;
- tt_info = list_entry(tt, struct xhci_tt_bw_info,
- tt_list);
- } while (tt_info->slot_id == slot_id);
}
int xhci_alloc_tt_info(struct xhci_hcd *xhci,
--
1.7.9.2
--
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