From: Will Deacon will.deacon@arm.com
When unmapping a range of pages in zap_pte_range, the page being unmapped is added to an mmu_gather_batch structure for asynchronous freeing. If we run out of space in the batch structure before the range has been completely unmapped, then we break out of the loop, force a TLB flush and free the pages that we have batched so far. If there are further pages to unmap, then we resume the loop where we left off.
Unfortunately, we forget to update addr when we break out of the loop, which causes us to truncate the range being invalidated as the end address is exclusive. When we re-enter the loop at the same address, the page has already been freed and the pte_present test will fail, meaning that we do not reconsider the address for invalidation.
This patch fixes the problem by incrementing addr by the PAGE_SIZE before breaking out of the loop on batch failure.
Signed-off-by: Will Deacon will.deacon@arm.com Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org --- mm/memory.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/mm/memory.c b/mm/memory.c index 1cc6bfb..3e50383 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1147,6 +1147,7 @@ again: print_bad_pte(vma, addr, ptent, page); if (unlikely(!__tlb_remove_page(tlb, page))) { force_flush = 1; + addr += PAGE_SIZE; break; } continue;