linux-kernel - [PATCH 3/3] vmalloc: back of when the current is killed

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Message-Id: <20170201092706.9966-4-mhocko@kernel.org>
Date:   Wed,  1 Feb 2017 10:27:06 +0100
From:   Michal Hocko <mhocko@...nel.org>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     Christoph Hellwig <hch@....de>,
        Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
        Al Viro <viro@...iv.linux.org.uk>, <linux-mm@...ck.org>,
        <linux-fsdevel@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Michal Hocko <mhocko@...e.com>
Subject: [PATCH 3/3] vmalloc: back of when the current is killed

From: Michal Hocko <mhocko@...e.com>

__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.

Signed-off-by: Michal Hocko <mhocko@...e.com>
---
 mm/vmalloc.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index d89034a393f2..011b446f8758 100644
--- 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
-- 
2.11.0