From: Mike Kravetz <mike.kravetz@oracle.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Muchun Song <songmuchun@bytedance.com>,
Miaohe Lin <linmiaohe@huawei.com>,
David Hildenbrand <david@redhat.com>,
Sven Schnelle <svens@linux.ibm.com>,
Michal Hocko <mhocko@suse.com>, Peter Xu <peterx@redhat.com>,
Naoya Horiguchi <naoya.horiguchi@linux.dev>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>,
Andrea Arcangeli <aarcange@redhat.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Davidlohr Bueso <dave@stgolabs.net>,
Prakash Sangappa <prakash.sangappa@oracle.com>,
James Houghton <jthoughton@google.com>,
Mina Almasry <almasrymina@google.com>,
Pasha Tatashin <pasha.tatashin@soleen.com>,
Axel Rasmussen <axelrasmussen@google.com>,
Ray Fucillo <Ray.Fucillo@intersystems.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 2/3] hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer
Date: Wed, 5 Oct 2022 20:30:30 -0700 [thread overview]
Message-ID: <Yz5L1uxQYR1VqFtJ@monkey> (raw)
In-Reply-To: <20221005011707.514612-3-mike.kravetz@oracle.com>
To address build issues:
From b6d359f77d32c7734fe4f00806a0ed1e99925534 Mon Sep 17 00:00:00 2001
From: Mike Kravetz <mike.kravetz@oracle.com>
Date: Wed, 5 Oct 2022 20:26:19 -0700
Subject: [PATCH 2/3] hugetlb: take hugetlb vma_lock when clearing
vma_lock->vma pointer
hugetlb file truncation/hole punch code may need to back out and take
locks in order in the routine hugetlb_unmap_file_folio(). This code
could race with vma freeing as pointed out in [1] and result in
accessing a stale vma pointer. To address this, take the vma_lock when
clearing the vma_lock->vma pointer.
[1] https://lore.kernel.org/linux-mm/01f10195-7088-4462-6def-909549c75ef4@huawei.com/
Fixes: "hugetlb: use new vma_lock for pmd sharing synchronization"
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
---
mm/hugetlb.c | 42 ++++++++++++++++++++++++++++++++----------
1 file changed, 32 insertions(+), 10 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 38c45aafe00f..e9194ca6d44b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -93,6 +93,7 @@ struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
static int hugetlb_acct_memory(struct hstate *h, long delta);
static void hugetlb_vma_lock_free(struct vm_area_struct *vma);
static void hugetlb_vma_lock_alloc(struct vm_area_struct *vma);
+static void __hugetlb_vma_unlock_write_free(struct vm_area_struct *vma);
static inline bool subpool_is_free(struct hugepage_subpool *spool)
{
@@ -5192,8 +5193,7 @@ void __unmap_hugepage_range_final(struct mmu_gather *tlb,
* be asynchrously deleted. If the page tables are shared, there
* will be issues when accessed by someone else.
*/
- hugetlb_vma_unlock_write(vma);
- hugetlb_vma_lock_free(vma);
+ __hugetlb_vma_unlock_write_free(vma);
i_mmap_unlock_write(vma->vm_file->f_mapping);
}
@@ -6942,6 +6942,30 @@ void hugetlb_vma_lock_release(struct kref *kref)
kfree(vma_lock);
}
+void __hugetlb_vma_unlock_write_put(struct hugetlb_vma_lock *vma_lock)
+{
+ struct vm_area_struct *vma = vma_lock->vma;
+
+ /*
+ * vma_lock structure may or not be released as a result of put,
+ * it certainly will no longer be attached to vma so clear pointer.
+ * Semaphore synchronizes access to vma_lock->vma field.
+ */
+ vma_lock->vma = NULL;
+ vma->vm_private_data = NULL;
+ up_write(&vma_lock->rw_sema);
+ kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
+}
+
+static void __hugetlb_vma_unlock_write_free(struct vm_area_struct *vma)
+{
+ if (__vma_shareable_flags_pmd(vma)) {
+ struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
+
+ __hugetlb_vma_unlock_write_put(vma_lock);
+ }
+}
+
static void hugetlb_vma_lock_free(struct vm_area_struct *vma)
{
/*
@@ -6953,14 +6977,8 @@ static void hugetlb_vma_lock_free(struct vm_area_struct *vma)
if (vma->vm_private_data) {
struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
- /*
- * vma_lock structure may or not be released, but it
- * certainly will no longer be attached to vma so clear
- * pointer.
- */
- vma_lock->vma = NULL;
- kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
- vma->vm_private_data = NULL;
+ down_write(&vma_lock->rw_sema);
+ __hugetlb_vma_unlock_write_put(vma_lock);
}
}
@@ -7111,6 +7129,10 @@ void hugetlb_vma_lock_release(struct kref *kref)
{
}
+static void __hugetlb_vma_unlock_write_free(struct vm_area_struct *vma)
+{
+}
+
static void hugetlb_vma_lock_free(struct vm_area_struct *vma)
{
}
--
2.37.3
next prev parent reply other threads:[~2022-10-06 3:31 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-05 1:17 [PATCH 0/3] hugetlb: fixes for new vma lock series Mike Kravetz
2022-10-05 1:17 ` [PATCH 1/3] hugetlb: fix vma lock handling during split vma and range unmapping Mike Kravetz
2022-10-15 1:25 ` Miaohe Lin
2022-10-18 2:56 ` Mike Kravetz
2022-10-18 6:25 ` Miaohe Lin
2022-10-05 1:17 ` [PATCH 2/3] hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer Mike Kravetz
2022-10-05 3:48 ` kernel test robot
2022-10-05 6:58 ` kernel test robot
2022-10-06 3:30 ` Mike Kravetz [this message]
2022-10-15 1:32 ` Miaohe Lin
2022-10-05 1:17 ` [PATCH 3/3] hugetlb: allocate vma lock for all sharable vmas Mike Kravetz
2022-10-15 1:40 ` Miaohe Lin
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