percpu: perform tlb flush after pcpu_map_pages() failure

commit 849f5169097e1ba35b90ac9df76b5bb6f9c0aabd upstream.

If pcpu_map_pages() fails midway, it unmaps the already mapped pages.
Currently, it doesn't flush tlb after the partial unmapping.  This may
be okay in most cases as the established mapping hasn't been used at
that point but it can go wrong and when it goes wrong it'd be
extremely difficult to track down.

Flush tlb after the partial unmapping.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c
index 8d9bb2c00c68d232ff6481969a3936054aa08387..51108165f829d777e4c69abe6109cb88ca4d7e14 100644 (file)
--- a/mm/percpu-vm.c
+++ b/mm/percpu-vm.c
@@ -272,6 +272,7 @@ err:
                __pcpu_unmap_pages(pcpu_chunk_addr(chunk, tcpu, page_start),
                                   page_end - page_start);
        }
+       pcpu_post_unmap_tlb_flush(chunk, page_start, page_end);
        return err;
 }