From b1948c627795378b536a39f054157a68aec08625 Mon Sep 17 00:00:00 2001 From: Liviu Dudau Date: Sat, 23 Feb 2019 09:50:27 +0800 Subject: [PATCH] mm/vmalloc.c: don't dereference possible NULL pointer in __vunmap() mainline inclusion from mainline-5.0-rc7 commit 22fa95e8071596d8442b07d4df2a49dbb7da7f94 category: bugfix bugzilla: 10656 CVE: NA ------------------------------------------------ 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: f3c01d2f3ade ("mm: vmalloc: avoid racy handling of debugobjects in vunmap") Signed-off-by: Liviu Dudau Reviewed-by: Andrew Morton Cc: Chintan Pandya Cc: Andrey Ryabinin Signed-off-by: Andrew Morton Signed-off-by: Stephen Rothwell Signed-off-by: zhong jiang Reviewed-by: Yang Yingliang Signed-off-by: Yang Yingliang --- mm/vmalloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index a728fc492557..b01d1a6c7577 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); -- GitLab