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authorOleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>2019-02-14 16:23:20 +0200
committerJuergen Gross <jgross@suse.com>2019-02-18 06:50:03 +0100
commitfa13e665e02874c0a5f4d06d6967ae34a6cb3d6a (patch)
treeebecfe859585e02ea8a0d14b605628411ccf893f /drivers/xen/gntdev-dmabuf.c
parent7681f31ec9cdacab4fd10570be924f2cef6669ba (diff)
xen/gntdev: Do not destroy context while dma-bufs are in use
If there are exported DMA buffers which are still in use and grant device is closed by either normal user-space close or by a signal this leads to the grant device context to be destroyed, thus making it not possible to correctly destroy those exported buffers when they are returned back to gntdev and makes the module crash: [ 339.617540] [<ffff00000854c0d8>] dmabuf_exp_ops_release+0x40/0xa8 [ 339.617560] [<ffff00000867a6e8>] dma_buf_release+0x60/0x190 [ 339.617577] [<ffff0000082211f0>] __fput+0x88/0x1d0 [ 339.617589] [<ffff000008221394>] ____fput+0xc/0x18 [ 339.617607] [<ffff0000080ed4e4>] task_work_run+0x9c/0xc0 [ 339.617622] [<ffff000008089714>] do_notify_resume+0xfc/0x108 Fix this by referencing gntdev on each DMA buffer export and unreferencing on buffer release. Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> Reviewed-by: Boris Ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
Diffstat (limited to 'drivers/xen/gntdev-dmabuf.c')
-rw-r--r--drivers/xen/gntdev-dmabuf.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/drivers/xen/gntdev-dmabuf.c b/drivers/xen/gntdev-dmabuf.c
index cba6b586bfbd..d97fcfc5e558 100644
--- a/drivers/xen/gntdev-dmabuf.c
+++ b/drivers/xen/gntdev-dmabuf.c
@@ -80,6 +80,12 @@ struct gntdev_dmabuf_priv {
struct list_head imp_list;
/* This is the lock which protects dma_buf_xxx lists. */
struct mutex lock;
+ /*
+ * We reference this file while exporting dma-bufs, so
+ * the grant device context is not destroyed while there are
+ * external users alive.
+ */
+ struct file *filp;
};
/* DMA buffer export support. */
@@ -311,6 +317,7 @@ static void dmabuf_exp_release(struct kref *kref)
dmabuf_exp_wait_obj_signal(gntdev_dmabuf->priv, gntdev_dmabuf);
list_del(&gntdev_dmabuf->next);
+ fput(gntdev_dmabuf->priv->filp);
kfree(gntdev_dmabuf);
}
@@ -423,6 +430,7 @@ static int dmabuf_exp_from_pages(struct gntdev_dmabuf_export_args *args)
mutex_lock(&args->dmabuf_priv->lock);
list_add(&gntdev_dmabuf->next, &args->dmabuf_priv->exp_list);
mutex_unlock(&args->dmabuf_priv->lock);
+ get_file(gntdev_dmabuf->priv->filp);
return 0;
fail:
@@ -834,7 +842,7 @@ long gntdev_ioctl_dmabuf_imp_release(struct gntdev_priv *priv,
return dmabuf_imp_release(priv->dmabuf_priv, op.fd);
}
-struct gntdev_dmabuf_priv *gntdev_dmabuf_init(void)
+struct gntdev_dmabuf_priv *gntdev_dmabuf_init(struct file *filp)
{
struct gntdev_dmabuf_priv *priv;
@@ -847,6 +855,8 @@ struct gntdev_dmabuf_priv *gntdev_dmabuf_init(void)
INIT_LIST_HEAD(&priv->exp_wait_list);
INIT_LIST_HEAD(&priv->imp_list);
+ priv->filp = filp;
+
return priv;
}