From: Liviu Dudau <liviu@xxxxxxxxxxx> Subject: 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@xxxxxxxxxxx Fixes: f3c01d2f3ade ("mm: vmalloc: avoid racy handling of debugobjects in vunmap") Signed-off-by: Liviu Dudau <liviu@xxxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Chintan Pandya <cpandya@xxxxxxxxxxxxxx> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/vmalloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/vmalloc.c~mm-vmallocc-dont-dereference-possible-null-pointer-in-__vunmap +++ a/mm/vmalloc.c @@ -1505,7 +1505,7 @@ static void __vunmap(const void *addr, i 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); _
