[v2,0/2] mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF

Message

Waiman Long Dec. 15, 2022, 4:02 p.m. UTC

It was found that a KASAN use-after-free error was reported in the
kmemleak_scan() function. After further examination, it is believe
that even though a reference is taken from the current object, it does
not prevent the object pointed to by the next pointer from going away
after a cond_resched().

To fix that, additional flags are added to make sure that the current
object won't be removed from the object_list during the duration of
the cond_resched() to ensure the validity of the next pointer.

While making the change, I also simplify the current usage of
kmemleak_cond_resched() to make it easier to understand.

Waiman Long (2):
  mm/kmemleak: Simplify kmemleak_cond_resched() usage
  mm/kmemleak: Fix UAF bug in kmemleak_scan()

 [v2: Update patch 2 to prevent object_list removal of current object]

 mm/kmemleak.c | 83 +++++++++++++++++++++++++--------------------------
 1 file changed, 41 insertions(+), 42 deletions(-)