| From | Paul Gortmaker <> | Subject | [v2.6.34-stable 065/165] xhci-mem.c: Check for ring->first_seg != NULL | Date | Wed, 15 Aug 2012 15:46:49 -0400 |
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From: Kautuk Consul <consul.kautuk@gmail.com>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git If you see a problem with using this for longterm, please comment. -------------------
commit 0e6c7f746ea99089fb3263709075c20485a479ae upstream.
There are 2 situations wherein the xhci_ring* might not get freed: - When xhci_ring_alloc() -> xhci_segment_alloc() returns NULL and we goto the fail: label in xhci_ring_alloc. In this case, the ring will not get kfreed. - When the num_segs argument to xhci_ring_alloc is passed as 0 and we try to free the rung after that. ( This doesn't really happen as of now in the code but we seem to be entertaining num_segs=0 in xhci_ring_alloc )
This should be backported to kernels as old as 2.6.31.
Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com> Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> --- drivers/usb/host/xhci-mem.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index 727ac40..31cf540 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -111,18 +111,20 @@ void xhci_ring_free(struct xhci_hcd *xhci, struct xhci_ring *ring) struct xhci_segment *seg; struct xhci_segment *first_seg; - if (!ring || !ring->first_seg) + if (!ring) return; - first_seg = ring->first_seg; - seg = first_seg->next; - xhci_dbg(xhci, "Freeing ring at %p\n", ring); - while (seg != first_seg) { - struct xhci_segment *next = seg->next; - xhci_segment_free(xhci, seg); - seg = next; + if (ring->first_seg) { + first_seg = ring->first_seg; + seg = first_seg->next; + xhci_dbg(xhci, "Freeing ring at %p\n", ring); + while (seg != first_seg) { + struct xhci_segment *next = seg->next; + xhci_segment_free(xhci, seg); + seg = next; + } + xhci_segment_free(xhci, first_seg); + ring->first_seg = NULL; } - xhci_segment_free(xhci, first_seg); - ring->first_seg = NULL; kfree(ring); } -- 1.7.12.rc2
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