FAILED: patch "[PATCH] hugetlb: don't delete vma_lock in hugetlb MADV_DONTNEED" failed to apply to 6.0-stable tree
The patch below does not apply to the 6.0-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Possible dependencies:
04ada095dcfc ("hugetlb: don't delete vma_lock in hugetlb MADV_DONTNEED processing") 21b85b09527c ("madvise: use zap_page_range_single for madvise dontneed") ecfbd733878d ("hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer") 131a79b474e9 ("hugetlb: fix vma lock handling during split vma and range unmapping") 40549ba8f8e0 ("hugetlb: use new vma_lock for pmd sharing synchronization") 378397ccb8e5 ("hugetlb: create hugetlb_unmap_file_folio to unmap single file folio") 8d9bfb260814 ("hugetlb: add vma based lock for pmd sharing") 12710fd69634 ("hugetlb: rename vma_shareable() and refactor code") c86272287bc6 ("hugetlb: create remove_inode_single_folio to remove single file folio") 7e1813d48dd3 ("hugetlb: rename remove_huge_page to hugetlb_delete_from_page_cache") 3a47c54f09c4 ("hugetlbfs: revert use i_mmap_rwsem for more pmd sharing synchronization") 188a39725ad7 ("hugetlbfs: revert use i_mmap_rwsem to address page fault/truncate race") 763ecb035029 ("mm: remove the vma linked list") 8220543df148 ("nommu: remove uses of VMA linked list") 11f9a21ab655 ("mm/mmap: reorganize munmap to use maple states") e99668a56430 ("mm/mmap: move mmap_region() below do_munmap()") 7964cf8caa4d ("mm: remove vmacache") 4dd1b84140c1 ("mm/mmap: use advanced maple tree API for mmap_region()") abdba2dda0c4 ("mm: use maple tree operations for find_vma_intersection()") 2e7ce7d354f2 ("mm/mmap: change do_brk_flags() to expand existing VMA and add do_brk_munmap()")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 04ada095dcfc4ae359418053c0be94453bdf1e84 Mon Sep 17 00:00:00 2001 From: Mike Kravetz mike.kravetz@oracle.com Date: Mon, 14 Nov 2022 15:55:06 -0800 Subject: [PATCH] hugetlb: don't delete vma_lock in hugetlb MADV_DONTNEED processing
madvise(MADV_DONTNEED) ends up calling zap_page_range() to clear page tables associated with the address range. For hugetlb vmas, zap_page_range will call __unmap_hugepage_range_final. However, __unmap_hugepage_range_final assumes the passed vma is about to be removed and deletes the vma_lock to prevent pmd sharing as the vma is on the way out. In the case of madvise(MADV_DONTNEED) the vma remains, but the missing vma_lock prevents pmd sharing and could potentially lead to issues with truncation/fault races.
This issue was originally reported here [1] as a BUG triggered in page_try_dup_anon_rmap. Prior to the introduction of the hugetlb vma_lock, __unmap_hugepage_range_final cleared the VM_MAYSHARE flag to prevent pmd sharing. Subsequent faults on this vma were confused as VM_MAYSHARE indicates a sharable vma, but was not set so page_mapping was not set in new pages added to the page table. This resulted in pages that appeared anonymous in a VM_SHARED vma and triggered the BUG.
Address issue by adding a new zap flag ZAP_FLAG_UNMAP to indicate an unmap call from unmap_vmas(). This is used to indicate the 'final' unmapping of a hugetlb vma. When called via MADV_DONTNEED, this flag is not set and the vm_lock is not deleted.
[1] https://lore.kernel.org/lkml/CAO4mrfdLMXsao9RF4fUE8-Wfde8xmjsKrTNMNC9wjUb6Ju...
Link: https://lkml.kernel.org/r/20221114235507.294320-3-mike.kravetz@oracle.com Fixes: 90e7e7f5ef3f ("mm: enable MADV_DONTNEED for hugetlb mappings") Signed-off-by: Mike Kravetz mike.kravetz@oracle.com Reported-by: Wei Chen harperchen1110@gmail.com Cc: Axel Rasmussen axelrasmussen@google.com Cc: David Hildenbrand david@redhat.com Cc: Matthew Wilcox willy@infradead.org Cc: Mina Almasry almasrymina@google.com Cc: Nadav Amit nadav.amit@gmail.com Cc: Naoya Horiguchi naoya.horiguchi@linux.dev Cc: Peter Xu peterx@redhat.com Cc: Rik van Riel riel@surriel.com Cc: Vlastimil Babka vbabka@suse.cz Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org
diff --git a/include/linux/mm.h b/include/linux/mm.h index cbfb489d381c..974ccca609d2 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1868,6 +1868,8 @@ struct zap_details { * default, the flag is not set. */ #define ZAP_FLAG_DROP_MARKER ((__force zap_flags_t) BIT(0)) +/* Set in unmap_vmas() to indicate a final unmap call. Only used by hugetlb */ +#define ZAP_FLAG_UNMAP ((__force zap_flags_t) BIT(1))
#ifdef CONFIG_MMU extern bool can_do_mlock(void); diff --git a/mm/hugetlb.c b/mm/hugetlb.c index f1385c3b6c96..e36ca75311a5 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5206,17 +5206,22 @@ void __unmap_hugepage_range_final(struct mmu_gather *tlb,
__unmap_hugepage_range(tlb, vma, start, end, ref_page, zap_flags);
- /* - * Unlock and free the vma lock before releasing i_mmap_rwsem. When - * the vma_lock is freed, this makes the vma ineligible for pmd - * sharing. And, i_mmap_rwsem is required to set up pmd sharing. - * This is important as page tables for this unmapped range will - * be asynchrously deleted. If the page tables are shared, there - * will be issues when accessed by someone else. - */ - __hugetlb_vma_unlock_write_free(vma); - - i_mmap_unlock_write(vma->vm_file->f_mapping); + if (zap_flags & ZAP_FLAG_UNMAP) { /* final unmap */ + /* + * Unlock and free the vma lock before releasing i_mmap_rwsem. + * When the vma_lock is freed, this makes the vma ineligible + * for pmd sharing. And, i_mmap_rwsem is required to set up + * pmd sharing. This is important as page tables for this + * unmapped range will be asynchrously deleted. If the page + * tables are shared, there will be issues when accessed by + * someone else. + */ + __hugetlb_vma_unlock_write_free(vma); + i_mmap_unlock_write(vma->vm_file->f_mapping); + } else { + i_mmap_unlock_write(vma->vm_file->f_mapping); + hugetlb_vma_unlock_write(vma); + } }
void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, diff --git a/mm/memory.c b/mm/memory.c index 9bc5edc35725..8c8420934d60 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1711,7 +1711,7 @@ void unmap_vmas(struct mmu_gather *tlb, struct maple_tree *mt, { struct mmu_notifier_range range; struct zap_details details = { - .zap_flags = ZAP_FLAG_DROP_MARKER, + .zap_flags = ZAP_FLAG_DROP_MARKER | ZAP_FLAG_UNMAP, /* Careful - we need to zap private pages too! */ .even_cows = true, };
On 12/03/22 12:22, gregkh@linuxfoundation.org wrote:
The patch below does not apply to the 6.0-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Not exactly sure of the policy here where the commit title does not apply to the backport. I left the title 'as is' and added a note about differences. The commit message already anticipated a backport and mentions this as well.
From d0c568ab5c0b2c2c3aae8a3dd04a7c41cf1088c9 Mon Sep 17 00:00:00 2001 From: Mike Kravetz mike.kravetz@oracle.com Date: Mon, 14 Nov 2022 15:55:06 -0800 Subject: [PATCH 2/2] hugetlb: don't delete vma_lock in hugetlb MADV_DONTNEED processing
commit 04ada095dcfc4ae359418053c0be94453bdf1e84 upstream.
madvise(MADV_DONTNEED) ends up calling zap_page_range() to clear page tables associated with the address range. For hugetlb vmas, zap_page_range will call __unmap_hugepage_range_final. However, __unmap_hugepage_range_final assumes the passed vma is about to be removed and deletes the vma_lock to prevent pmd sharing as the vma is on the way out. In the case of madvise(MADV_DONTNEED) the vma remains, but the missing vma_lock prevents pmd sharing and could potentially lead to issues with truncation/fault races.
This issue was originally reported here [1] as a BUG triggered in page_try_dup_anon_rmap. Prior to the introduction of the hugetlb vma_lock, __unmap_hugepage_range_final cleared the VM_MAYSHARE flag to prevent pmd sharing. Subsequent faults on this vma were confused as VM_MAYSHARE indicates a sharable vma, but was not set so page_mapping was not set in new pages added to the page table. This resulted in pages that appeared anonymous in a VM_SHARED vma and triggered the BUG.
Address issue by adding a new zap flag ZAP_FLAG_UNMAP to indicate an unmap call from unmap_vmas(). This is used to indicate the 'final' unmapping of a hugetlb vma. When called via MADV_DONTNEED, this flag is not set and the vm_lock is not deleted.
NOTE - Prior to the introduction of the huegtlb vma_lock in v6.1, this issue is addressed by not clearing the VM_MAYSHARE flag when __unmap_hugepage_range_final is called in the MADV_DONTNEED case.
[1] https://lore.kernel.org/lkml/CAO4mrfdLMXsao9RF4fUE8-Wfde8xmjsKrTNMNC9wjUb6Ju...
Link: https://lkml.kernel.org/r/20221114235507.294320-3-mike.kravetz@oracle.com Fixes: 90e7e7f5ef3f ("mm: enable MADV_DONTNEED for hugetlb mappings") Signed-off-by: Mike Kravetz mike.kravetz@oracle.com Reported-by: Wei Chen harperchen1110@gmail.com Cc: Axel Rasmussen axelrasmussen@google.com Cc: David Hildenbrand david@redhat.com Cc: Matthew Wilcox willy@infradead.org Cc: Mina Almasry almasrymina@google.com Cc: Nadav Amit nadav.amit@gmail.com Cc: Naoya Horiguchi naoya.horiguchi@linux.dev Cc: Peter Xu peterx@redhat.com Cc: Rik van Riel riel@surriel.com Cc: Vlastimil Babka vbabka@suse.cz Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Mike Kravetz mike.kravetz@oracle.com --- include/linux/mm.h | 2 ++ mm/hugetlb.c | 25 ++++++++++++++----------- mm/memory.c | 2 +- 3 files changed, 17 insertions(+), 12 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h index 7368a99e4e55..fa4d973c1363 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1794,6 +1794,8 @@ struct zap_details { * default, the flag is not set. */ #define ZAP_FLAG_DROP_MARKER ((__force zap_flags_t) BIT(0)) +/* Set in unmap_vmas() to indicate a final unmap call. Only used by hugetlb */ +#define ZAP_FLAG_UNMAP ((__force zap_flags_t) BIT(1))
#ifdef CONFIG_MMU extern bool can_do_mlock(void); diff --git a/mm/hugetlb.c b/mm/hugetlb.c index dbb558e71e9e..022a3bfafec4 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5145,17 +5145,20 @@ void __unmap_hugepage_range_final(struct mmu_gather *tlb, { __unmap_hugepage_range(tlb, vma, start, end, ref_page, zap_flags);
- /* - * Clear this flag so that x86's huge_pmd_share page_table_shareable - * test will fail on a vma being torn down, and not grab a page table - * on its way out. We're lucky that the flag has such an appropriate - * name, and can in fact be safely cleared here. We could clear it - * before the __unmap_hugepage_range above, but all that's necessary - * is to clear it before releasing the i_mmap_rwsem. This works - * because in the context this is called, the VMA is about to be - * destroyed and the i_mmap_rwsem is held. - */ - vma->vm_flags &= ~VM_MAYSHARE; + if (zap_flags & ZAP_FLAG_UNMAP) { /* final unmap */ + /* + * Clear this flag so that x86's huge_pmd_share + * page_table_shareable test will fail on a vma being torn + * down, and not grab a page table on its way out. We're lucky + * that the flag has such an appropriate name, and can in fact + * be safely cleared here. We could clear it before the + * __unmap_hugepage_range above, but all that's necessary + * is to clear it before releasing the i_mmap_rwsem. This works + * because in the context this is called, the VMA is about to + * be destroyed and the i_mmap_rwsem is held. + */ + vma->vm_flags &= ~VM_MAYSHARE; + } }
void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, diff --git a/mm/memory.c b/mm/memory.c index 68d5b3dcec2e..a0fdaa74091f 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1712,7 +1712,7 @@ void unmap_vmas(struct mmu_gather *tlb, { struct mmu_notifier_range range; struct zap_details details = { - .zap_flags = ZAP_FLAG_DROP_MARKER, + .zap_flags = ZAP_FLAG_DROP_MARKER | ZAP_FLAG_UNMAP, /* Careful - we need to zap private pages too! */ .even_cows = true, };
linux-stable-mirror@lists.linaro.org
-
gregkh＠linuxfoundation.org -
Mike Kravetz