lib/test_hmm.c: handle src_pfns and dst_pfns allocation failure

The kcalloc() in dmirror_device_evict_chunk() will return null if the
physical memory has run out.  As a result, if src_pfns or dst_pfns is
dereferenced, the null pointer dereference bug will happen.

Moreover, the device is going away.  If the kcalloc() fails, the pages
mapping a chunk could not be evicted.  So add a __GFP_NOFAIL flag in
kcalloc().

Finally, as there is no need to have physically contiguous memory, Switch
kcalloc() to kvcalloc() in order to avoid failing allocations.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: b2ef9f5a5cb3 ("mm/hmm/test: add selftest driver for HMM")
Signed-off-by: Duoming Zhou <[email protected]>
Cc: Jérôme Glisse <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions