From: Laurent Dufour <ldufour@linux.vnet.ibm.com>
To: paulmck@linux.vnet.ibm.com, peterz@infradead.org,
akpm@linux-foundation.org, kirill@shutemov.name,
ak@linux.intel.com, mhocko@kernel.org, dave@stgolabs.net,
jack@suse.cz, Matthew Wilcox <willy@infradead.org>,
benh@kernel.crashing.org, mpe@ellerman.id.au, paulus@samba.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
hpa@zytor.com, Will Deacon <will.deacon@arm.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com,
npiggin@gmail.com, bsingharora@gmail.com,
Tim Chen <tim.c.chen@linux.intel.com>,
linuxppc-dev@lists.ozlabs.org, x86@kernel.org
Subject: [PATCH v2 08/20] mm: Protect SPF handler against anon_vma changes
Date: Fri, 18 Aug 2017 00:05:07 +0200 [thread overview]
Message-ID: <1503007519-26777-9-git-send-email-ldufour@linux.vnet.ibm.com> (raw)
In-Reply-To: <1503007519-26777-1-git-send-email-ldufour@linux.vnet.ibm.com>
The speculative page fault handler must be protected against anon_vma
changes. This is because page_add_new_anon_rmap() is called during the
speculative path.
In addition, don't try speculative page fault if the VMA don't have an
anon_vma structure allocated because its allocation should be
protected by the mmap_sem.
In __vma_adjust() when importer->anon_vma is set, there is no need to
protect against speculative page faults since speculative page fault
is aborted if the vma->anon_vma is not set.
When calling page_add_new_anon_rmap() vma->anon_vma is necessarily
valid since we checked for it when locking the pte and the anon_vma is
removed once the pte is unlocked. So even if the speculative page
fault handler is running concurrently with do_unmap(), as the pte is
locked in unmap_region() - through unmap_vmas() - and the anon_vma
unlinked later, because we check for the vma sequence counter which is
updated in unmap_page_range() before locking the pte, and then in
free_pgtables() so when locking the pte the change will be detected.
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
---
mm/memory.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/mm/memory.c b/mm/memory.c
index da3bd07bb052..68e4fdcce692 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -615,7 +615,9 @@ void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
* Hide vma from rmap and truncate_pagecache before freeing
* pgtables
*/
+ write_seqcount_begin(&vma->vm_sequence);
unlink_anon_vmas(vma);
+ write_seqcount_end(&vma->vm_sequence);
unlink_file_vma(vma);
if (is_vm_hugetlb_page(vma)) {
@@ -629,7 +631,9 @@ void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
&& !is_vm_hugetlb_page(next)) {
vma = next;
next = vma->vm_next;
+ write_seqcount_begin(&vma->vm_sequence);
unlink_anon_vmas(vma);
+ write_seqcount_end(&vma->vm_sequence);
unlink_file_vma(vma);
}
free_pgd_range(tlb, addr, vma->vm_end,
--
2.7.4
next prev parent reply other threads:[~2017-08-17 22:11 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-17 22:04 [PATCH v2 00/20] Speculative page faults Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 01/20] mm: Dont assume page-table invariance during faults Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 02/20] mm: Prepare for FAULT_FLAG_SPECULATIVE Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 03/20] mm: Introduce pte_spinlock " Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 04/20] mm: VMA sequence count Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 05/20] mm: Protect VMA modifications using " Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 06/20] mm: RCU free VMAs Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 07/20] mm: Cache some VMA fields in the vm_fault structure Laurent Dufour
2017-08-17 22:05 ` Laurent Dufour [this message]
2017-08-17 22:05 ` [PATCH v2 09/20] mm/migrate: Pass vm_fault pointer to migrate_misplaced_page() Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 10/20] mm: Introduce __lru_cache_add_active_or_unevictable Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 11/20] mm: Introduce __maybe_mkwrite() Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 12/20] mm: Introduce __vm_normal_page() Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 13/20] mm: Introduce __page_add_new_anon_rmap() Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 14/20] mm: Provide speculative fault infrastructure Laurent Dufour
2017-08-20 12:11 ` Sergey Senozhatsky
2017-08-25 8:52 ` Laurent Dufour
2017-08-27 0:18 ` Kirill A. Shutemov
2017-08-28 9:37 ` Peter Zijlstra
2017-08-28 21:14 ` Benjamin Herrenschmidt
2017-08-28 22:35 ` Andi Kleen
2017-08-29 8:15 ` Peter Zijlstra
2017-08-29 8:33 ` Peter Zijlstra
2017-08-29 11:27 ` Peter Zijlstra
2017-08-29 21:19 ` Benjamin Herrenschmidt
2017-08-30 6:13 ` Peter Zijlstra
2017-08-29 7:59 ` Laurent Dufour
2017-08-29 12:04 ` Peter Zijlstra
2017-08-29 13:18 ` Laurent Dufour
2017-08-29 13:45 ` Peter Zijlstra
2017-08-30 5:03 ` Anshuman Khandual
2017-08-30 5:58 ` Peter Zijlstra
2017-08-30 9:32 ` Laurent Dufour
2017-08-31 6:55 ` Anshuman Khandual
2017-08-31 7:31 ` Peter Zijlstra
2017-08-30 9:53 ` Laurent Dufour
2017-08-30 3:48 ` Anshuman Khandual
2017-08-30 5:25 ` Anshuman Khandual
2017-08-30 8:56 ` Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 15/20] mm: Try spin lock in speculative path Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 16/20] mm: Adding speculative page fault failure trace events Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 17/20] perf: Add a speculative page fault sw event Laurent Dufour
2017-08-21 8:55 ` Anshuman Khandual
2017-08-22 1:46 ` Michael Ellerman
2017-08-17 22:05 ` [PATCH v2 18/20] perf tools: Add support for the SPF perf event Laurent Dufour
2017-08-21 8:48 ` Anshuman Khandual
2017-08-25 8:53 ` Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 19/20] x86/mm: Add speculative pagefault handling Laurent Dufour
2017-08-21 7:29 ` Anshuman Khandual
2017-08-29 14:50 ` Laurent Dufour
2017-08-29 14:58 ` Laurent Dufour
2017-08-17 22:05 ` [PATCH v2 20/20] powerpc/mm: Add speculative page fault Laurent Dufour
2017-08-21 6:58 ` Anshuman Khandual
2017-08-29 15:13 ` Laurent Dufour
2017-08-21 2:26 ` [PATCH v2 00/20] Speculative page faults Sergey Senozhatsky
2017-09-08 9:24 ` Laurent Dufour
2017-09-11 0:45 ` Sergey Senozhatsky
2017-09-11 6:28 ` Laurent Dufour
2017-08-21 6:28 ` Anshuman Khandual
2017-08-22 0:41 ` Paul E. McKenney
2017-08-25 9:41 ` Laurent Dufour
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