Commit 6ade2032 authored Mar 05, 2019 by Liviu Dudau Committed by Linus Torvalds Mar 05, 2019

mm/vmalloc.c: don't dereference possible NULL pointer in __vunmap()

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.

Link: http://lkml.kernel.org/r/20181228171009.22269-1-liviu@dudau.co.uk


Fixes: f3c01d2f ("mm: vmalloc: avoid racy handling of debugobjects in vunmap")
Signed-off-by: Liviu Dudau <liviu@dudau.co.uk>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Chintan Pandya <cpandya@codeaurora.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent abd02ac6

mm/vmalloc.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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);

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