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From: Liviu Dudau <liviu@dudau.co.uk>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Chintan Pandya <cpandya@codeaurora.org>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
	Liviu Dudau <liviu@dudau.co.uk>
Subject: [PATCH] mm/vmalloc.c: don't dereference possible NULL pointer in __vunmap.
Date: Fri, 28 Dec 2018 17:10:09 +0000	[thread overview]
Message-ID: <20181228171009.22269-1-liviu@dudau.co.uk> (raw)

find_vmap_area() can return a NULL pointer and we're going to dereference
it without checking it first. Use the existing find_vm_area() function
which does exactly what we want and checks for the NULL pointer.

Fixes: f3c01d2f3ade ("mm: vmalloc: avoid racy handling of debugobjects
in vunmap")

Signed-off-by: Liviu Dudau <liviu@dudau.co.uk>
---
 mm/vmalloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 871e41c55e239..806047d7fda3c 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1505,7 +1505,7 @@ static void __vunmap(const void *addr, int deallocate_pages)
 			addr))
 		return;
 
-	area = find_vmap_area((unsigned long)addr)->vm;
+	area = find_vm_area(addr);
 	if (unlikely(!area)) {
 		WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
 				addr);
-- 
2.20.1


                 reply	other threads:[~2018-12-28 17:15 UTC|newest]

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