From: Konstantin Khlebnikov <[email protected]> This check effectively catches anon vma hierarchy inconsistence and some vma corruptions. It was effective for catching corner cases in anon vma reusing logic. For now this code seems stable so check could be hidden under CONFIG_DEBUG_VM and replaced with WARN because it's not so fatal.
Signed-off-by: Konstantin Khlebnikov <[email protected]> Suggested-by: Vasily Averin <[email protected]> Acked-by: Vlastimil Babka <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> (cherry picked from commit e4c5800a3991f0c6a766983535dfc10d51802cf6) Signed-off-by: Arnd Bergmann <[email protected]> --- mm/rmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/rmap.c b/mm/rmap.c index 488dda209431..cf733fab230f 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -408,7 +408,7 @@ void unlink_anon_vmas(struct vm_area_struct *vma) list_for_each_entry_safe(avc, next, &vma->anon_vma_chain, same_vma) { struct anon_vma *anon_vma = avc->anon_vma; - BUG_ON(anon_vma->degree); + VM_WARN_ON(anon_vma->degree); put_anon_vma(anon_vma); list_del(&avc->same_vma); -- 2.20.0
