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dataplane: do not free VirtQueueElement in vring_push() 

VirtQueueElement is allocated in vring_pop() so it seems to make sense
that vring_push() should free it.  Alas, virtio-blk frees
VirtQueueElement itself in virtio_blk_free_request().

This patch solves a double-free assertion in glib's g_slice_free().

Rename vring_free_element() to vring_unmap_element() since it no longer
frees the VirtQueueElement.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2014-07-09 10:05:47 +02:00 committed by Kevin Wolf
parent 0a21ea3289
commit abd764250f
2 changed files with 4 additions and 6 deletions
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9
hw/virtio/dataplane/vring.c
View File

@ -272,7 +272,7 @@ static int get_indirect(Vring *vring, VirtQueueElement *elem,
return 0; return 0;
} }
void vring_free_element(VirtQueueElement *elem) static void vring_unmap_element(VirtQueueElement *elem)
{ {
int i; int i;
@ -287,8 +287,6 @@ void vring_free_element(VirtQueueElement *elem)
for (i = 0; i < elem->in_num; i++) { for (i = 0; i < elem->in_num; i++) {
vring_unmap(elem->in_sg[i].iov_base, true); vring_unmap(elem->in_sg[i].iov_base, true);
} }
g_slice_free(VirtQueueElement, elem);
} }
/* This looks in the virtqueue and for the first available buffer, and converts /* This looks in the virtqueue and for the first available buffer, and converts
@ -402,7 +400,8 @@ out:
vring->broken = true; vring->broken = true;
} }
if (elem) { if (elem) {
vring_free_element(elem); vring_unmap_element(elem);
g_slice_free(VirtQueueElement, elem);
} }
*p_elem = NULL; *p_elem = NULL;
return ret; return ret;
@ -418,7 +417,7 @@ void vring_push(Vring *vring, VirtQueueElement *elem, int len)
unsigned int head = elem->index; unsigned int head = elem->index;
uint16_t new; uint16_t new;
vring_free_element(elem); vring_unmap_element(elem);
/* Don't touch vring if a fatal error occurred */ /* Don't touch vring if a fatal error occurred */
if (vring->broken) { if (vring->broken) {

1
include/hw/virtio/dataplane/vring.h
View File

@ -55,6 +55,5 @@ bool vring_enable_notification(VirtIODevice *vdev, Vring *vring);
bool vring_should_notify(VirtIODevice *vdev, Vring *vring); bool vring_should_notify(VirtIODevice *vdev, Vring *vring);
int vring_pop(VirtIODevice *vdev, Vring *vring, VirtQueueElement **elem); int vring_pop(VirtIODevice *vdev, Vring *vring, VirtQueueElement **elem);
void vring_push(Vring *vring, VirtQueueElement *elem, int len); void vring_push(Vring *vring, VirtQueueElement *elem, int len);
void vring_free_element(VirtQueueElement *elem);
#endif /* VRING_H */ #endif /* VRING_H */