In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: f_fs: Fix fence cleanup in ffs_dmabuf_transfer() error paths
The error paths for endpoint-disabled (ESHUTDOWN) and request-allocation
failure (ENOMEM) in ffs_dmabuf_transfer() jump to err_fence_put which
calls dma_fence_put() on the fence. However, at that point the fence has
only been kmalloc’d — dma_fence_init() has not been called yet, so the
refcount and the fence ops are uninitialized. Calling dma_fence_put() on
such an object leads to undefined behavior.
Use kfree() instead, since the fence is just a plain allocation at this
stage, and rename the label to err_fence_free to reflect the actual
cleanup action.
