From: Catalin Marinas <catalin.marinas@arm.com>
To: Will Deacon <will@kernel.org>
Cc: Zhenyu Ye <yezhenyu2@huawei.com>,
aneesh.kumar@linux.ibm.com, Marc Zyngier <maz@kernel.org>,
steven.price@arm.com, Peter Zijlstra <peterz@infradead.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
linux-mm@kvack.org, Xiexiangyou <xiexiangyou@huawei.com>,
liushixin2@huawei.com, huyaqin <huyaqin1@huawei.com>,
zhurui3@huawei.com
Subject: Re: [PATCH v1] arm64: tlb: fix the TTL value of tlb_get_level
Date: Wed, 23 Jun 2021 12:28:21 +0100 [thread overview]
Message-ID: <20210623112819.GB3718@arm.com> (raw)
In-Reply-To: <20210623110412.GA32177@willie-the-truck>
On Wed, Jun 23, 2021 at 12:04:12PM +0100, Will Deacon wrote:
> On Wed, Jun 23, 2021 at 03:05:22PM +0800, Zhenyu Ye wrote:
> > The TTL field indicates the level of page table walk holding the *leaf*
> > entry for the address being invalidated. But currently, the TTL field
> > may be set to an incorrent value in the following stack:
> >
> > pte_free_tlb
> > __pte_free_tlb
> > tlb_remove_table
> > tlb_table_invalidate
> > tlb_flush_mmu_tlbonly
> > tlb_flush
> >
> > In this case, we just want to flush a PTE page, but the tlb->cleared_pmds
> > is set and we get tlb_level = 2 in the tlb_get_level() function. This may
> > cause some unexpected problems.
> >
> > This patch set the TTL field to 0 if tlb->freed_tables is set. The
> > tlb->freed_tables indicates page table pages are freed, not the leaf
> > entry.
> >
> > Fixes: c4ab2cbc1d87 ("arm64: tlb: Set the TTL field in flush_tlb_range")
> > Reported-by: ZhuRui <zhurui3@huawei.com>
> > Signed-off-by: Zhenyu Ye <yezhenyu2@huawei.com>
> > ---
> > arch/arm64/include/asm/tlb.h | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/arch/arm64/include/asm/tlb.h b/arch/arm64/include/asm/tlb.h
> > index 61c97d3b58c7..c995d1f4594f 100644
> > --- a/arch/arm64/include/asm/tlb.h
> > +++ b/arch/arm64/include/asm/tlb.h
> > @@ -28,6 +28,10 @@ static void tlb_flush(struct mmu_gather *tlb);
> > */
> > static inline int tlb_get_level(struct mmu_gather *tlb)
> > {
> > + /* The TTL field is only valid for the leaf entry. */
> > + if (tlb->freed_tables)
> > + return 0;
> > +
> > if (tlb->cleared_ptes && !(tlb->cleared_pmds ||
> > tlb->cleared_puds ||
> > tlb->cleared_p4ds))
>
> Thanks. I can't see a better way around this, so I'll queue the patch.
If you haven't queued it already, feel free to add:
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
I'd also add:
Cc: <stable@vger.kernel.org> # 5.9.x
--
Catalin
next prev parent reply other threads:[~2021-06-23 11:28 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-23 7:05 [PATCH v1] arm64: tlb: fix the TTL value of tlb_get_level Zhenyu Ye
2021-06-23 11:04 ` Will Deacon
2021-06-23 11:28 ` Catalin Marinas [this message]
2021-06-24 1:55 ` Zhenyu Ye
2021-06-24 8:29 ` Will Deacon
2021-06-23 14:00 ` Will Deacon
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