From: Andrea Arcangeli <aarcange@redhat.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Yu Zhao <yuzhao@google.com>, Andy Lutomirski <luto@kernel.org>,
Peter Xu <peterx@redhat.com>, Pavel Emelyanov <xemul@openvz.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Minchan Kim <minchan@kernel.org>, Will Deacon <will@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Matthew Wilcox <willy@infradead.org>,
Oleg Nesterov <oleg@redhat.com>, Jann Horn <jannh@google.com>,
Kees Cook <keescook@chromium.org>,
John Hubbard <jhubbard@nvidia.com>,
Leon Romanovsky <leonro@nvidia.com>,
Jason Gunthorpe <jgg@ziepe.ca>, Jan Kara <jack@suse.cz>,
Kirill Tkhai <ktkhai@virtuozzo.com>
Subject: [PATCH 1/2] mm: proc: Invalidate TLB after clearing soft-dirty page state
Date: Thu, 7 Jan 2021 15:04:01 -0500 [thread overview]
Message-ID: <20210107200402.31095-2-aarcange@redhat.com> (raw)
In-Reply-To: <20210107200402.31095-1-aarcange@redhat.com>
From: Will Deacon <will@kernel.org>
Since commit 0758cd830494 ("asm-generic/tlb: avoid potential double
flush"), TLB invalidation is elided in tlb_finish_mmu() if no entries
were batched via the tlb_remove_*() functions. Consequently, the
page-table modifications performed by clear_refs_write() in response to
a write to /proc/<pid>/clear_refs do not perform TLB invalidation.
Although this is fine when simply aging the ptes, in the case of
clearing the "soft-dirty" state we can end up with entries where
pte_write() is false, yet a writable mapping remains in the TLB.
Fix this by avoiding the mmu_gather API altogether: managing both the
'tlb_flush_pending' flag on the 'mm_struct' and explicit TLB
invalidation for the sort-dirty path, much like mprotect() does already.
Fixes: 0758cd830494 ("asm-generic/tlb: avoid potential double flush")
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
---
fs/proc/task_mmu.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index ee5a235b3056..a127262ba517 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1189,7 +1189,6 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
struct mm_struct *mm;
struct vm_area_struct *vma;
enum clear_refs_types type;
- struct mmu_gather tlb;
int itype;
int rv;
@@ -1234,7 +1233,6 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
count = -EINTR;
goto out_mm;
}
- tlb_gather_mmu(&tlb, mm, 0, -1);
if (type == CLEAR_REFS_SOFT_DIRTY) {
for (vma = mm->mmap; vma; vma = vma->vm_next) {
if (!(vma->vm_flags & VM_SOFTDIRTY))
@@ -1252,15 +1250,18 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
break;
}
+ inc_tlb_flush_pending(mm);
mmu_notifier_range_init(&range, MMU_NOTIFY_SOFT_DIRTY,
0, NULL, mm, 0, -1UL);
mmu_notifier_invalidate_range_start(&range);
}
walk_page_range(mm, 0, mm->highest_vm_end, &clear_refs_walk_ops,
&cp);
- if (type == CLEAR_REFS_SOFT_DIRTY)
+ if (type == CLEAR_REFS_SOFT_DIRTY) {
mmu_notifier_invalidate_range_end(&range);
- tlb_finish_mmu(&tlb, 0, -1);
+ flush_tlb_mm(mm);
+ dec_tlb_flush_pending(mm);
+ }
mmap_read_unlock(mm);
out_mm:
mmput(mm);
next prev parent reply other threads:[~2021-01-07 20:05 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-25 9:25 [RFC PATCH v2 0/2] mm: fix races due to deferred TLB flushes Nadav Amit
2020-12-25 9:25 ` [RFC PATCH v2 1/2] mm/userfaultfd: fix memory corruption due to writeprotect Nadav Amit
2021-01-04 12:22 ` Peter Zijlstra
2021-01-04 19:24 ` Andrea Arcangeli
2021-01-04 19:35 ` Nadav Amit
2021-01-04 20:19 ` Andrea Arcangeli
2021-01-04 20:39 ` Nadav Amit
2021-01-04 21:01 ` Andrea Arcangeli
2021-01-04 21:26 ` Nadav Amit
2021-01-05 18:45 ` Andrea Arcangeli
2021-01-05 19:05 ` Nadav Amit
2021-01-05 19:45 ` Andrea Arcangeli
2021-01-05 20:06 ` Nadav Amit
2021-01-05 21:06 ` Andrea Arcangeli
2021-01-05 21:43 ` Peter Xu
2021-01-05 8:13 ` Peter Zijlstra
2021-01-05 8:52 ` Nadav Amit
2021-01-05 14:26 ` Peter Zijlstra
2021-01-05 8:58 ` Peter Zijlstra
2021-01-05 9:22 ` Nadav Amit
2021-01-05 17:58 ` Andrea Arcangeli
2021-01-05 15:08 ` Peter Xu
2021-01-05 18:08 ` Andrea Arcangeli
2021-01-05 18:41 ` Peter Xu
2021-01-05 18:55 ` Andrea Arcangeli
2021-01-05 19:07 ` Nadav Amit
2021-01-05 19:43 ` Peter Xu
2020-12-25 9:25 ` [RFC PATCH v2 2/2] fs/task_mmu: acquire mmap_lock for write on soft-dirty cleanup Nadav Amit
2021-01-05 15:08 ` Will Deacon
2021-01-05 18:20 ` Andrea Arcangeli
2021-01-05 19:26 ` Nadav Amit
2021-01-05 20:39 ` Andrea Arcangeli
2021-01-05 21:20 ` Yu Zhao
2021-01-05 21:22 ` Nadav Amit
2021-01-05 22:16 ` Will Deacon
2021-01-06 0:29 ` Andrea Arcangeli
2021-01-06 0:02 ` Andrea Arcangeli
2021-01-07 20:04 ` [PATCH 0/2] page_count can't be used to decide when wp_page_copy Andrea Arcangeli
2021-01-07 20:04 ` Andrea Arcangeli [this message]
2021-01-07 20:04 ` [PATCH 2/2] mm: soft_dirty: userfaultfd: introduce wrprotect_tlb_flush_pending Andrea Arcangeli
2021-01-07 20:17 ` Linus Torvalds
2021-01-07 20:25 ` Linus Torvalds
2021-01-07 20:58 ` Andrea Arcangeli
2021-01-07 21:29 ` Linus Torvalds
2021-01-07 21:53 ` John Hubbard
2021-01-07 22:00 ` Linus Torvalds
2021-01-07 22:14 ` John Hubbard
2021-01-07 22:20 ` Linus Torvalds
2021-01-07 22:24 ` Linus Torvalds
2021-01-07 22:37 ` John Hubbard
2021-01-15 11:27 ` Jan Kara
2021-01-07 22:31 ` Andrea Arcangeli
2021-01-07 22:42 ` Linus Torvalds
2021-01-07 22:51 ` Linus Torvalds
2021-01-07 23:48 ` Andrea Arcangeli
2021-01-08 0:25 ` Linus Torvalds
2021-01-08 12:48 ` Will Deacon
2021-01-08 16:14 ` Andrea Arcangeli
2021-01-08 17:39 ` Linus Torvalds
2021-01-08 17:53 ` Andrea Arcangeli
2021-01-08 19:25 ` Linus Torvalds
2021-01-09 0:12 ` Andrea Arcangeli
2021-01-08 17:30 ` Linus Torvalds
2021-01-07 23:28 ` Andrea Arcangeli
2021-01-07 21:36 ` kernel test robot
2021-01-07 20:25 ` [PATCH 0/2] page_count can't be used to decide when wp_page_copy Jason Gunthorpe
2021-01-07 20:32 ` Linus Torvalds
2021-01-07 21:05 ` Linus Torvalds
2021-01-07 22:02 ` Andrea Arcangeli
2021-01-07 22:17 ` Linus Torvalds
2021-01-07 22:56 ` Andrea Arcangeli
2021-01-09 19:32 ` Matthew Wilcox
2021-01-09 19:46 ` Linus Torvalds
2021-01-15 14:30 ` Jan Kara
2021-01-07 21:54 ` Andrea Arcangeli
2021-01-07 21:45 ` Andrea Arcangeli
2021-01-08 13:36 ` Jason Gunthorpe
2021-01-08 17:00 ` Andrea Arcangeli
2021-01-08 18:19 ` Jason Gunthorpe
2021-01-08 18:31 ` Andy Lutomirski
2021-01-08 18:38 ` Linus Torvalds
2021-01-08 23:34 ` Andrea Arcangeli
2021-01-09 19:03 ` Andy Lutomirski
2021-01-09 19:15 ` Linus Torvalds
2021-01-08 18:59 ` Linus Torvalds
2021-01-08 22:43 ` Andrea Arcangeli
2021-01-09 0:42 ` Jason Gunthorpe
2021-01-09 2:50 ` Andrea Arcangeli
2021-01-11 14:30 ` Jason Gunthorpe
2021-01-13 21:56 ` Jerome Glisse
2021-01-13 23:39 ` Jason Gunthorpe
2021-01-14 2:35 ` Jerome Glisse
[not found] ` <20210109034958.6928-1-hdanton@sina.com>
2021-01-11 14:39 ` Jason Gunthorpe
2021-01-05 21:55 ` [RFC PATCH v2 2/2] fs/task_mmu: acquire mmap_lock for write on soft-dirty cleanup Peter Xu
2021-03-02 22:13 ` [RFC PATCH v2 0/2] mm: fix races due to deferred TLB flushes Peter Xu
2021-03-02 22:14 ` Nadav Amit
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