Commit e4c5800a authored May 19, 2016 by Konstantin Khlebnikov Committed by Linus Torvalds May 19, 2016

mm/rmap: replace BUG_ON(anon_vma->degree) with VM_WARN_ON

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 <khlebnikov@yandex-team.ru>
Suggested-by: Vasily Averin <vvs@virtuozzo.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent fee83b3a

mm/rmap.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -409,7 +409,7 @@ 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);