From: Fenghua Yu <fenghua.yu@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Tony Luck <tony.luck@intel.com>,
Lu Baolu <baolu.lu@linux.intel.com>,
Joerg Roedel <joro@8bytes.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Jacob Pan <jacob.jun.pan@linux.intel.com>,
Ashok Raj <ashok.raj@intel.com>,
Ravi V Shankar <ravi.v.shankar@intel.com>,
iommu@lists.linux-foundation.org, x86 <x86@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 05/11] iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit
Date: Thu, 27 Jan 2022 18:42:00 -0800 [thread overview]
Message-ID: <YfNVBzN67rSu/QcE@otcwcpicx3.sc.intel.com> (raw)
In-Reply-To: <8735la41qb.ffs@tglx>
Hi, Thomas,
On Wed, Jan 26, 2022 at 10:38:04PM +0100, Thomas Gleixner wrote:
> On Wed, Jan 26 2022 at 09:36, Fenghua Yu wrote:
> > On Wed, Jan 26, 2022 at 03:23:42PM +0100, Thomas Gleixner wrote:
> >> On Tue, Jan 25 2022 at 07:18, Fenghua Yu wrote:
> >> While looking at ioasid_put() usage I tripped over the following UAF
> >> issue:
> >>
> >> --- a/drivers/iommu/intel/iommu.c
> >> +++ b/drivers/iommu/intel/iommu.c
> >> @@ -4817,8 +4817,10 @@ static int aux_domain_add_dev(struct dma
> >> auxiliary_unlink_device(domain, dev);
> >> link_failed:
> >> spin_unlock_irqrestore(&device_domain_lock, flags);
> >> - if (list_empty(&domain->subdevices) && domain->default_pasid > 0)
> >> + if (list_empty(&domain->subdevices) && domain->default_pasid > 0) {
> >> ioasid_put(domain->default_pasid);
> >> + domain->default_pasid = INVALID_IOASID;
> >> + }
> >>
> >> return ret;
> >> }
> >> @@ -4847,8 +4849,10 @@ static void aux_domain_remove_dev(struct
> >>
> >> spin_unlock_irqrestore(&device_domain_lock, flags);
> >>
> >> - if (list_empty(&domain->subdevices) && domain->default_pasid > 0)
> >> + if (list_empty(&domain->subdevices) && domain->default_pasid > 0) {
> >> ioasid_put(domain->default_pasid);
> >> + domain->default_pasid = INVALID_IOASID;
> >> + }
> >> }
> >>
> >> static int prepare_domain_attach_device(struct iommu_domain *domain,
> >
> > The above patch fixes an existing issue. I will put it in a separate patch,
> > right?
>
> Correct.
>
> > It cannot be applied cleanly to the upstream tree. Do you want me to base
> > the above patch (and the whole patch set) to the upstream tree or a specific
> > tip branch?
>
> Against Linus tree please so that the bugfix applies.
>
> > I will fold the following patch into patch #5. The patch #11 (the doc patch)
> > also needs to remove one paragraph talking about refcount.
> >
> > So I will send the whole patch set with the following changes:
> > 1. One new bug fix patch (the above patch)
When I study your above aux_domain bug fix path, I find more aux_domain bugs.
But then I find aux_domain will be completely removed because all aux_domain
related callbacks are not called and are dead code (no wonder there are
so many bugs in aux_domain). Please see this series: https://lore.kernel.org/linux-iommu/20220124071103.2097118-4-baolu.lu@linux.intel.com/
For the series, Baolu confirms that he is "pretty sure that should be part
of v5.18". And I don't find the series calls any IOASID function after
removing the aux_domain code.
So that means we don't need to fix those issues in the dead aux_domain
code any more because it will be completely removed in 5.18, right?
If you agree, I will not include the aux_domain fix patch or any other
aux_domain fix patches in the up-coming v3. Is that OK?
> > 2. Updated patch #5 (with the following patch folded)
I will still change ioasid_put() in the aux_domain callbacks to ioasid_free()
in patch #5. So compilation will pass. Baolu's series will remove
the entire aux_domain code in 5.18.
> > 3. Updated patch #11 (removing refcount description)
>
> Looks good.
>
Thanks.
-Fenghua
next prev parent reply other threads:[~2022-01-28 2:42 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-17 22:01 [PATCH v2 00/11] Re-enable ENQCMD and PASID MSR Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 01/11] iommu/sva: Rename CONFIG_IOMMU_SVA_LIB to CONFIG_IOMMU_SVA Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 02/11] mm: Change CONFIG option for mm->pasid field Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 03/11] iommu/ioasid: Introduce a helper to check for valid PASIDs Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 04/11] kernel/fork: Initialize mm's PASID Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 05/11] iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit Fenghua Yu
2022-01-24 20:21 ` Thomas Gleixner
2022-01-24 20:33 ` Fenghua Yu
2022-01-24 20:36 ` Thomas Gleixner
2022-01-24 20:52 ` Fenghua Yu
2022-01-24 20:55 ` Thomas Gleixner
2022-01-25 15:18 ` Fenghua Yu
2022-01-26 14:23 ` Thomas Gleixner
2022-01-26 17:36 ` Fenghua Yu
2022-01-26 21:38 ` Thomas Gleixner
2022-01-28 2:42 ` Fenghua Yu [this message]
2022-01-28 14:53 ` Thomas Gleixner
2021-12-17 22:01 ` [PATCH v2 06/11] x86/fpu: Clear PASID when copying fpstate Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 07/11] sched: Define and initialize a flag to identify valid PASID in the task Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 08/11] x86/traps: Demand-populate PASID MSR via #GP Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 09/11] x86/cpufeatures: Re-enable ENQCMD Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 10/11] tools/objtool: Check for use of the ENQCMD instruction in the kernel Fenghua Yu
2021-12-17 22:57 ` Josh Poimboeuf
2021-12-27 17:50 ` Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 11/11] docs: x86: Change documentation for SVA (Shared Virtual Addressing) Fenghua Yu
2021-12-27 17:52 ` [PATCH v2 00/11] Re-enable ENQCMD and PASID MSR Fenghua Yu
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