[4.4,45/48] mm/vmalloc.c: dont dereference possible NULL pointer in __vunmap()
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Message ID 20200601174004.957880557@linuxfoundation.org
State New
Headers show
Series
  • Untitled series #446653
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Commit Message

Greg KH June 1, 2020, 5:53 p.m. UTC
From: Liviu Dudau <liviu@dudau.co.uk>

commit 6ade20327dbb808882888ed8ccded71e93067cf9 upstream.

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 <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>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 mm/vmalloc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch
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--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1464,7 +1464,7 @@  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);