From ba422731316dde1e22dcc84b83c7349dc0ce1c3c Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 9 Jan 2019 16:51:17 -0800 Subject: [PATCH] mm/mmu_notifier: mm/rmap.c: Fix a mmu_notifier range bug in try_to_unmap_one MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The conversion to use a structure for mmu_notifier_invalidate_range_*() unintentionally changed the usage in try_to_unmap_one() to init the 'struct mmu_notifier_range' with vma->vm_start instead of @address, i.e. it invalidates the wrong address range. Revert to the correct address range. Manifests as KVM use-after-free WARNINGs and subsequent "BUG: Bad page state in process X" errors when reclaiming from a KVM guest due to KVM removing the wrong pages from its own mappings. Reported-by: leozinho29_eu@hotmail.com Reported-by: Mike Galbraith Reported-and-tested-by: Adam Borowski Reviewed-by: Jérôme Glisse Reviewed-by: Pankaj gupta Cc: Christian König Cc: Jan Kara Cc: Matthew Wilcox Cc: Ross Zwisler Cc: Dan Williams Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Michal Hocko Cc: Felix Kuehling Cc: Ralph Campbell Cc: John Hubbard Cc: Andrew Morton Fixes: ac46d4f3c432 ("mm/mmu_notifier: use structure for invalidate_range_start/end calls v2") Signed-off-by: Sean Christopherson Signed-off-by: Linus Torvalds --- mm/rmap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index 68a1a5b869a5..0454ecc29537 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1371,8 +1371,8 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma, * Note that the page can not be free in this function as call of * try_to_unmap() must hold a reference on the page. */ - mmu_notifier_range_init(&range, vma->vm_mm, vma->vm_start, - min(vma->vm_end, vma->vm_start + + mmu_notifier_range_init(&range, vma->vm_mm, address, + min(vma->vm_end, address + (PAGE_SIZE << compound_order(page)))); if (PageHuge(page)) { /* -- 2.30.2