mm/hmm: add missing unmaps of the ptep during hmm_vma_handle_pte() (dfdc2207) · Commits · 戴 / test

Many of the direct returns of error skipped doing the pte_unmap(). All non zero exit paths must unmap the pte. The pte_unmap() is split unnaturally like this because some of the error exit paths trigger a sleep and must release the lock before sleeping. Fixes: ("mm/hmm: allow to mirror vma of a file on a DAX backed filesystem") Fixes: ("mm/hmm: factor out pte and pmd handling to simplify hmm_vma_walk_pmd()") Reviewed-by:

Ralph Campbell <rcampbell@nvidia.com> Reviewed-by:

Christoph Hellwig <hch@lst.de> Signed-off-by:

Jason Gunthorpe <jgg@mellanox.com>

mm/hmm.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -325,6 +325,7 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
		}

		/* Report error for everything else */
		pte_unmap(ptep);
		*pfn = range->values[HMM_PFN_ERROR];
		return -EFAULT;
		} else {
		@@ -339,10 +340,13 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
		if (pte_devmap(pte)) {
		hmm_vma_walk->pgmap = get_dev_pagemap(pte_pfn(pte),
		hmm_vma_walk->pgmap);
		if (unlikely(!hmm_vma_walk->pgmap))
		if (unlikely(!hmm_vma_walk->pgmap)) {
		pte_unmap(ptep);
		return -EBUSY;
		}
		} else if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) && pte_special(pte)) {
		if (!is_zero_pfn(pte_pfn(pte))) {
		pte_unmap(ptep);
		*pfn = range->values[HMM_PFN_SPECIAL];
		return -EFAULT;
		}
		@@ -437,7 +441,7 @@ again:

		r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, &pfns[i]);
		if (r) {
		/* hmm_vma_handle_pte() did unmap pte directory */
		/* hmm_vma_handle_pte() did pte_unmap() */
		hmm_vma_walk->last = addr;
		return r;
		}

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