From: Peter Xu <peterx@redhat.com>
To: Alistair Popple <apopple@nvidia.com>
Cc: linux-mm@kvack.org, akpm@linux-foundation.org,
Nadav Amit <nadav.amit@gmail.com>,
huang ying <huang.ying.caritas@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
"Sierra Guiza, Alejandro (Alex)" <alex.sierra@amd.com>,
Felix Kuehling <Felix.Kuehling@amd.com>,
Jason Gunthorpe <jgg@nvidia.com>,
John Hubbard <jhubbard@nvidia.com>,
David Hildenbrand <david@redhat.com>,
Ralph Campbell <rcampbell@nvidia.com>,
Matthew Wilcox <willy@infradead.org>,
Karol Herbst <kherbst@redhat.com>, Lyude Paul <lyude@redhat.com>,
Ben Skeggs <bskeggs@redhat.com>,
Logan Gunthorpe <logang@deltatee.com>,
paulus@ozlabs.org, linuxppc-dev@lists.ozlabs.org, "Huang,
Ying" <ying.huang@intel.com>,
stable@vger.kernel.org
Subject: Re: [PATCH v4 1/4] mm/migrate_device.c: Flush TLB while holding PTL
Date: Fri, 2 Sep 2022 16:35:47 -0400 [thread overview]
Message-ID: <YxJpIwPn0FGOka0C@xz-m1.local> (raw)
In-Reply-To: <9f801e9d8d830408f2ca27821f606e09aa856899.1662078528.git-series.apopple@nvidia.com>
On Fri, Sep 02, 2022 at 10:35:51AM +1000, Alistair Popple wrote:
> When clearing a PTE the TLB should be flushed whilst still holding the
> PTL to avoid a potential race with madvise/munmap/etc. For example
> consider the following sequence:
>
> CPU0 CPU1
> ---- ----
>
> migrate_vma_collect_pmd()
> pte_unmap_unlock()
> madvise(MADV_DONTNEED)
> -> zap_pte_range()
> pte_offset_map_lock()
> [ PTE not present, TLB not flushed ]
> pte_unmap_unlock()
> [ page is still accessible via stale TLB ]
> flush_tlb_range()
>
> In this case the page may still be accessed via the stale TLB entry
> after madvise returns. Fix this by flushing the TLB while holding the
> PTL.
>
> Signed-off-by: Alistair Popple <apopple@nvidia.com>
> Reported-by: Nadav Amit <nadav.amit@gmail.com>
> Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
> Fixes: 8c3328f1f36a ("mm/migrate: migrate_vma() unmap page from vma while collecting pages")
> Cc: stable@vger.kernel.org
Acked-by: Peter Xu <peterx@redhat.com>
--
Peter Xu
prev parent reply other threads:[~2022-09-02 20:35 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-02 0:35 [PATCH v4 1/4] mm/migrate_device.c: Flush TLB while holding PTL Alistair Popple
2022-09-02 0:35 ` [PATCH v4 2/4] mm/migrate_device.c: Add missing flush_cache_page() Alistair Popple
2022-09-02 6:51 ` David Hildenbrand
2022-09-02 20:39 ` Peter Xu
2022-09-02 0:35 ` [PATCH v4 3/4] mm/migrate_device.c: Copy pte dirty bit to page Alistair Popple
2022-09-02 6:53 ` David Hildenbrand
2022-09-02 0:35 ` [PATCH v4 4/4] selftests/hmm-tests: Add test for dirty bits Alistair Popple
2022-09-05 0:41 ` John Hubbard
2022-09-07 11:13 ` Alistair Popple
2022-09-07 21:48 ` John Hubbard
2022-09-13 2:33 ` Alistair Popple
2022-09-02 6:51 ` [PATCH v4 1/4] mm/migrate_device.c: Flush TLB while holding PTL David Hildenbrand
2022-09-02 20:35 ` Peter Xu [this message]
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