vmalloc: back off when the current task is killed

__vmalloc_area_node() allocates pages to cover the requested vmalloc
size.  This can be a lot of memory.  If the current task is killed by
the OOM killer, and thus has an unlimited access to memory reserves, it
can consume all the memory theoretically.  Fix this by checking for
fatal_signal_pending and back off early.

Link: http://lkml.kernel.org/r/20170201092706.9966-4-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index d89034a393f276457118b0696613c92c83ae8fcc..011b446f87583b94a6353670dc5ce3f94faf7299 100644 (file)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1642,6 +1642,11 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
        for (i = 0; i < area->nr_pages; i++) {
                struct page *page;
 
+               if (fatal_signal_pending(current)) {
+                       area->nr_pages = i;
+                       goto fail;
+               }
+
                if (node == NUMA_NO_NODE)
                        page = alloc_page(alloc_mask);
                else