Re: [BUG 3.7-rc5] NULL pointer deref when using a pcie-pci bridgedpci device and intel-iommu

From: Alex Williamson
Date: Tue Nov 13 2012 - 14:10:52 EST

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In reply to: Don Dutile: "Re: [BUG 3.7-rc5] NULL pointer deref when using a pcie-pci bridgedpci device and intel-iommu"
Next in thread: Matthew Thode: "Re: [BUG 3.7-rc5] NULL pointer deref when using a pcie-pci bridgedpci device and intel-iommu"
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On Tue, 2012-11-13 at 14:05 -0500, Don Dutile wrote:
> On 11/13/2012 10:38 AM, Alex Williamson wrote:
> > On Mon, 2012-11-12 at 15:05 -0600, Matthew Thode wrote:
> >> On 11/12/2012 01:57 PM, Don Dutile wrote:
> >>> On 11/12/2012 04:26 AM, Doug Goldstein wrote:
> >>>> On Sun, Nov 11, 2012 at 5:19 PM, Matthew Thode
> >>>> <prometheanfire@xxxxxxxxxx> wrote:
> >>>>> System boots with vt-d disabled in bios. Otherwise I get the errors in
> >>>>> the attached log. I can do whatever testing you need as this system is
> >>>>> not in production yet. gonna paste the important part here. Let me
> >>>>> know if you want anything else.
> >>>>>
> >>>>> Please CC me directly as I am not subscribed to the LKML.
> >>>>>
> >>>>>
> >>>>> Trying to unpack rootfs image as initramfs...
> >>>>> Freeing initrd memory: 5124k freed
> >>>>> IOMMU 0 0xfbffe000: using Queued invalidation
> >>>>> IOMMU: Setting RMRR:
> >>>>> IOMMU: Setting identity map for device 0000:00:1d.0 [0xbf7ec000 -
> >>>>> 0xbf7fffff]
> >>>>> IOMMU: Setting identity map for device 0000:00:1d.1 [0xbf7ec000 -
> >>>>> 0xbf7fffff]
> >>>>> IOMMU: Setting identity map for device 0000:00:1d.2 [0xbf7ec000 -
> >>>>> 0xbf7fffff]
> >>>>> IOMMU: Setting identity map for device 0000:00:1d.7 [0xbf7ec000 -
> >>>>> 0xbf7fffff]
> >>>>> IOMMU: Setting identity map for device 0000:00:1a.0 [0xbf7ec000 -
> >>>>> 0xbf7fffff]
> >>>>> IOMMU: Setting identity map for device 0000:00:1a.1 [0xbf7ec000 -
> >>>>> 0xbf7fffff]
> >>>>> IOMMU: Setting identity map for device 0000:00:1a.2 [0xbf7ec000 -
> >>>>> 0xbf7fffff]
> >>>>> IOMMU: Setting identity map for device 0000:00:1a.7 [0xbf7ec000 -
> >>>>> 0xbf7fffff]
> >>>>> IOMMU: Setting identity map for device 0000:00:1d.0 [0xec000 - 0xeffff]
> >>>>> IOMMU: Setting identity map for device 0000:00:1d.1 [0xec000 - 0xeffff]
> >>>>> IOMMU: Setting identity map for device 0000:00:1d.2 [0xec000 - 0xeffff]
> >>>>> IOMMU: Setting identity map for device 0000:00:1d.7 [0xec000 - 0xeffff]
> >>>>> IOMMU: Setting identity map for device 0000:00:1a.0 [0xec000 - 0xeffff]
> >>>>> IOMMU: Setting identity map for device 0000:00:1a.1 [0xec000 - 0xeffff]
> >>>>> IOMMU: Setting identity map for device 0000:00:1a.2 [0xec000 - 0xeffff]
> >>>>> IOMMU: Setting identity map for device 0000:00:1a.7 [0xec000 - 0xeffff]
> >>>>> IOMMU: Prepare 0-16MiB unity mapping for LPC
> >>>>> IOMMU: Setting identity map for device 0000:00:1f.0 [0x0 - 0xffffff]
> >>>>> PCI-DMA: Intel(R) Virtualization Technology for Directed I/O
> >>>>> BUG: unable to handle kernel NULL pointer dereference at
> >>>>> 000000000000003c
> >>>>> IP: [<ffffffff813bd796>] pci_get_dma_source+0xf/0x41
> >>>>> PGD 0
> >>>>> Oops: 0000 [#1] SMP
> >>>>> Modules linked in:
> >>>>> CPU 7
> >>>>> Pid: 1, comm: swapper/0 Not tainted 3.7.0-rc5 #1 Penguin Computing
> >>>>> Relion 1751/X8DTU
> >>>>> RIP: 0010:[<ffffffff813bd796>] [<ffffffff813bd796>]
> >>>>> pci_get_dma_source+0xf/0x41
> >>>>> RSP: 0000:ffff8806264d1d88 EFLAGS: 00010282
> >>>>> RAX: ffffffff813bd3a8 RBX: ffff8806261d1000 RCX: 00000000e8221180
> >>>>> RDX: ffffffff818624f0 RSI: ffff88062635b0c0 RDI: 0000000000000000
> >>>>> RBP: ffff8806264d1d88 R08: ffff8806263d6000 R09: 00000000ffffffff
> >>>>> R10: ffff8806264d1ca8 R11: 0000000000000005 R12: 0000000000000000
> >>>>> R13: ffff8806261d1098 R14: 0000000000000000 R15: 0000000000000000
> >>>>> FS: 0000000000000000(0000) GS:ffff88063f2e0000(0000)
> >>>>> knlGS:0000000000000000
> >>>>> CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> >>>>> CR2: 000000000000003c CR3: 0000000001c0b000 CR4: 00000000000007e0
> >>>>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> >>>>> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> >>>>> Process swapper/0 (pid: 1, threadinfo ffff8806264d0000, task
> >>>>> ffff8806264cf910)
> >>>>> Stack:
> >>>>> ffff8806264d1dc8 ffffffff815d02c9 0000000000000000 ffff880600000000
> >>>>> ffff8806264d1dd8 ffffffff81c64b00 ffff8806261d1098 ffff8806264d1df8
> >>>>> ffff8806264d1de8 ffffffff815cd5a4 ffffffff81c64b00 ffffffff815cd56a
> >>>>> Call Trace:
> >>>>> [<ffffffff815d02c9>] intel_iommu_add_device+0x95/0x167
> >>>>> [<ffffffff815cd5a4>] add_iommu_group+0x3a/0x41
> >>>>> [<ffffffff815cd56a>] ? bus_set_iommu+0x44/0x44
> >>>>> [<ffffffff8145eca1>] bus_for_each_dev+0x54/0x81
> >>>>> [<ffffffff815cd563>] bus_set_iommu+0x3d/0x44
> >>>>> [<ffffffff81cd3fa3>] intel_iommu_init+0xae5/0xb5e
> >>>>> [<ffffffff81ca0277>] ? free_initrd+0x9e/0x9e
> >>>>> [<ffffffff81ca4248>] ? memblock_find_dma_reserve+0x13f/0x13f
> >>>>> [<ffffffff81ca425e>] pci_iommu_init+0x16/0x41
> >>>>> [<ffffffff81cc4140>] ? pci_proc_init+0x6b/0x6b
> >>>>> [<ffffffff81000231>] do_one_initcall+0x7a/0x129
> >>>>> [<ffffffff816dac14>] kernel_init+0x139/0x2a2
> >>>>> [<ffffffff81c9d4c7>] ? loglevel+0x31/0x31
> >>>>> [<ffffffff816daadb>] ? rest_init+0x6f/0x6f
> >>>>> [<ffffffff816f66ac>] ret_from_fork+0x7c/0xb0
> >>>>> [<ffffffff816daadb>] ? rest_init+0x6f/0x6f
> >>>>> Code: ff c1 75 04 ff d0 eb 12 48 83 c2 10 48 8b 42 08 48 85 c0 75 d3 b8
> >>>>> e7 ff ff ff c9 c3 55 48 c7 c2 f0 24 86 81 48 89 e5 eb 24 8b 0a<66> 3b
> >>>>> 4f 3c 74 05 66 ff c1 75 13 66 8b 4a 02 66 3b 4f 3e 74 05
> >>>>> RIP [<ffffffff813bd796>] pci_get_dma_source+0xf/0x41
> >>>>> RSP<ffff8806264d1d88>
> >>>>> CR2: 000000000000003c
> >>>>> ---[ end trace 5c5a2ceca067e0ec ]---
> >>>>> Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009
> >>>>>
> >>>>> ------------[ cut here ]------------
> >>>>> WARNING: at arch/x86/kernel/smp.c:123
> >>>>> native_smp_send_reschedule+0x25/0x51()
> >>>>> Hardware name: Relion 1751
> >>>>> Modules linked in:
> >>>>> Pid: 1, comm: swapper/0 Tainted: G D 3.7.0-rc5 #1
> >>>>> Call Trace:
> >>>>> <IRQ> [<ffffffff810968ee>] warn_slowpath_common+0x80/0x98
> >>>>> [<ffffffff8109691b>] warn_slowpath_null+0x15/0x17
> >>>>> [<ffffffff8104e1a3>] native_smp_send_reschedule+0x25/0x51
> >>>>> [<ffffffff810bc81b>] trigger_load_balance+0x1e8/0x214
> >>>>> [<ffffffff810b731f>] scheduler_tick+0xd8/0xe1
> >>>>> [<ffffffff810a132f>] update_process_times+0x62/0x73
> >>>>> [<ffffffff810cb78b>] tick_sched_timer+0x7c/0x9b
> >>>>> [<ffffffff810b0f83>] __run_hrtimer.clone.24+0x4e/0xc1
> >>>>> [<ffffffff810b15b0>] hrtimer_interrupt+0xc7/0x1ac
> >>>>> [<ffffffff8104ef01>] smp_apic_timer_interrupt+0x81/0x94
> >>>>> [<ffffffff816f71ca>] apic_timer_interrupt+0x6a/0x70
> >>>>> <EOI> [<ffffffff81097ffc>] ? console_unlock+0x2c2/0x2ed
> >>>>> [<ffffffff816f32fc>] ? panic+0x189/0x1c5
> >>>>> [<ffffffff816f3261>] ? panic+0xee/0x1c5
> >>>>> [<ffffffff8109ab6b>] do_exit+0x357/0x7b2
> >>>>> [<ffffffff810371b8>] oops_end+0xb2/0xba
> >>>>> [<ffffffff8105841d>] no_context+0x266/0x275
> >>>>> [<ffffffff810585e7>] __bad_area_nosemaphore+0x1bb/0x1db
> >>>>> [<ffffffff8118de46>] ? sysfs_addrm_finish+0x2f/0xa6
> >>>>> [<ffffffff81058615>] bad_area_nosemaphore+0xe/0x10
> >>>>> [<ffffffff81058bdb>] __do_page_fault+0x360/0x39f
> >>>>> [<ffffffff81394afa>] ? ida_get_new_above+0xf9/0x19e
> >>>>> [<ffffffff8112a077>] ? slab_node+0x59/0xa2
> >>>>> [<ffffffff816f3ffd>] ? mutex_unlock+0x9/0xb
> >>>>> [<ffffffff816da653>] ? klist_put+0x4c/0x70
> >>>>> [<ffffffff816da581>] ? klist_next+0x30/0xb6
> >>>>> [<ffffffff813b8cf9>] ? pci_do_find_bus+0x49/0x49
> >>>>> [<ffffffff81058c42>] do_page_fault+0x9/0xb
> >>>>> [<ffffffff816f6232>] page_fault+0x22/0x30
> >>>>> [<ffffffff813bd3a8>] ? nv_msi_ht_cap_quirk_all+0x10/0x10
> >>>>> [<ffffffff813bd796>] ? pci_get_dma_source+0xf/0x41
> >>>>> [<ffffffff815d02c9>] intel_iommu_add_device+0x95/0x167
> >>>>> [<ffffffff815cd5a4>] add_iommu_group+0x3a/0x41
> >>>>> [<ffffffff815cd56a>] ? bus_set_iommu+0x44/0x44
> >>>>> [<ffffffff8145eca1>] bus_for_each_dev+0x54/0x81
> >>>>> [<ffffffff815cd563>] bus_set_iommu+0x3d/0x44
> >>>>> [<ffffffff81cd3fa3>] intel_iommu_init+0xae5/0xb5e
> >>>>> [<ffffffff81ca0277>] ? free_initrd+0x9e/0x9e
> >>>>> [<ffffffff81ca4248>] ? memblock_find_dma_reserve+0x13f/0x13f
> >>>>> [<ffffffff81ca425e>] pci_iommu_init+0x16/0x41
> >>>>> [<ffffffff81cc4140>] ? pci_proc_init+0x6b/0x6b
> >>>>> [<ffffffff81000231>] do_one_initcall+0x7a/0x129
> >>>>> [<ffffffff816dac14>] kernel_init+0x139/0x2a2
> >>>>> [<ffffffff81c9d4c7>] ? loglevel+0x31/0x31
> >>>>> [<ffffffff816daadb>] ? rest_init+0x6f/0x6f
> >>>>> [<ffffffff816f66ac>] ret_from_fork+0x7c/0xb0
> >>>>> [<ffffffff816daadb>] ? rest_init+0x6f/0x6f
> >>>>> ---[ end trace 5c5a2ceca067e0ed ]---
> >>>>>
> >>>>> --
> >>>>> -- Matthew Thode (prometheanfire)
> >>>>
> >>>> The root cause of Matt's issue is that intel_iommu_add_device() calls
> >>>> pci_get_domain_bus_and_slot() which is returning NULL. Which is not an
> >>>> expected value. The reason NULL is being returned is that Matt has a
> >>>> card with a TI XIO2000A/XIO2200A PCIe-PCI bridge (VID: 104C, DID:
> >>>> 8231) on it. This device already has a quirk setup for disabling fast
> >>>> back to back transfers on its secondary bus. If we cause it to use the
> >>>> primary bus, that appears to resolve the issue. I'm not sure exactly
> >>>> how to proceed from here due to relative lack of knowledge of PCI. Do
> >>>> all PCIe-PCI bridges with secondary buses need their DMA parent to be
> >>>> the primary bus or is that just something that should be done for the
> >>>> TI XIO2000A due to the existing quirk?
> >>>>
> >>> DMA from a (legacy) PCI device does not have a SRC-ID in the transaction,
> >>> so the source of the device generating the DMA is unknown. When bridging
> >>> to a PCIe device, the Parent PPB's dev-id is inserted on the PCIe as the
> >>> source
> >>> of a transaction -- in this case, DMA read/write transaction.
> >>> This (sw) mapping should have happened by default, unless a recent
> >>> change from VFIO
> >>> broke this mapping.... or the TI bridge didn't report itself correctly
> >>> as a PCIe-PCI bridge.
> >>> Alex ?
> >>>
> >>>
> >>>> The failing call with arguments was pci_get_domain_bus_and_slot(0, 5,
> >>>> 0), while pci_get_domain_bus_and_slot(0, 4, 0) resulted in a system
> >>>> that didn't panic and a device that worked.
> >>>>
> >>>> $ lspci -tvn
> >>>> -+-[0000:ff]-+-00.0 8086:2c40
> >>>> | +-00.1 8086:2c01
> >>>> | +-02.0 8086:2c10
> >>>> | +-02.1 8086:2c11
> >>>> | +-02.4 8086:2c14
> >>>> | +-02.5 8086:2c15
> >>>> | +-03.0 8086:2c18
> >>>> | +-03.1 8086:2c19
> >>>> | +-03.2 8086:2c1a
> >>>> | +-03.4 8086:2c1c
> >>>> | +-04.0 8086:2c20
> >>>> | +-04.1 8086:2c21
> >>>> | +-04.2 8086:2c22
> >>>> | +-04.3 8086:2c23
> >>>> | +-05.0 8086:2c28
> >>>> | +-05.1 8086:2c29
> >>>> | +-05.2 8086:2c2a
> >>>> | +-05.3 8086:2c2b
> >>>> | +-06.0 8086:2c30
> >>>> | +-06.1 8086:2c31
> >>>> | +-06.2 8086:2c32
> >>>> | \-06.3 8086:2c33
> >>>> \-[0000:00]-+-00.0 8086:3406
> >>>> +-01.0-[01]--+-00.0 8086:10c9
> >>>> | \-00.1 8086:10c9
> >>>> +-03.0-[02]--
> >>>> +-05.0-[03]--
> >>>> +-07.0-[04-05]----00.0-[05]----08.0 d161:8006
> >>>> +-09.0-[06]----00.0 8086:10b9
> >>>> +-13.0 8086:342d
> >>>> +-14.0 8086:342e
> >>>> +-14.1 8086:3422
> >>>> +-14.2 8086:3423
> >>>> +-14.3 8086:3438
> >>>> +-16.0 8086:3430
> >>>> +-16.1 8086:3431
> >>>> +-16.2 8086:3432
> >>>> +-16.3 8086:3433
> >>>> +-16.4 8086:3429
> >>>> +-16.5 8086:342a
> >>>> +-16.6 8086:342b
> >>>> +-16.7 8086:342c
> >>>> +-1a.0 8086:3a37
> >>>> +-1a.1 8086:3a38
> >>>> +-1a.2 8086:3a39
> >>>> +-1a.7 8086:3a3c
> >>>> +-1d.0 8086:3a34
> >>>> +-1d.1 8086:3a35
> >>>> +-1d.2 8086:3a36
> >>>> +-1d.7 8086:3a3a
> >>>> +-1e.0-[07]----01.0 102b:0532
> >>>> +-1f.0 8086:3a16
> >>>> +-1f.2 8086:3a22
> >>>> \-1f.3 8086:3a30
> >>>>
> >>>> If someone can craft the correct patch that'd be great or answer the
> >>>> above question and I'll gladly craft it.
> >>>>
> >>>> Thanks.
> >>>
> >> because I didn't see it. Here was the patch that got it working for me
> >> (ignore the printks), applies against 3.6.6 and 3.7-rc5.
> >
> > I think you're on the right track, but the solution is too specific.
> > Here's a version that will fall back to the bridge device for the base
> > of the group. There may be opportunities to get rid of the pci_get_
> > call altogether, but this seems pretty safe. Can you please test it?
> > Thanks,
> >
> > Alex
> >
> going through the logic, I don't see why the pci_get_domain_bus_and_slot()
> is even called. once there is a !NULL return for bridge, then
> it should just do the pci_dev_get(bridge).

I agree, if we were earlier in the 3.7 cycle I think I'd drop it
altogether, but I'm nervous that we're forgetting something and opted to
only fix the clearly broken path. I can queue a patch for 3.8 that does
the remaining cleanup. Thanks,

Alex

> > commit ca15170f05b140ab8c611db5cb7cb9c218ddc930
> > Author: Alex Williamson<alex.williamson@xxxxxxxxxx>
> > Date: Tue Nov 13 08:34:08 2012 -0700
> >
> > intel-iommu: Fix lookup in add device
> >
> > We can't assume this device exists, fall back to the bridge itself.
> >
> > Signed-off-by: Alex Williamson<alex.williamson@xxxxxxxxxx>
> >
> > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> > index d4a4cd4..0badfa4 100644
> > --- a/drivers/iommu/intel-iommu.c
> > +++ b/drivers/iommu/intel-iommu.c
> > @@ -4108,7 +4108,7 @@ static void swap_pci_ref(struct pci_dev **from, struct pci_dev *to)
> > static int intel_iommu_add_device(struct device *dev)
> > {
> > struct pci_dev *pdev = to_pci_dev(dev);
> > - struct pci_dev *bridge, *dma_pdev;
> > + struct pci_dev *bridge, *dma_pdev = NULL;
> > struct iommu_group *group;
> > int ret;
> >
> > @@ -4122,7 +4122,7 @@ static int intel_iommu_add_device(struct device *dev)
> > dma_pdev = pci_get_domain_bus_and_slot(
> > pci_domain_nr(pdev->bus),
> > bridge->subordinate->number, 0);
> > - else
> > + if (!dma_pdev)
> > dma_pdev = pci_dev_get(bridge);
> > } else
> > dma_pdev = pci_dev_get(pdev);
> >
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> > the body of a message to majordomo@xxxxxxxxxxxxxxx
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
>

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Next message: John Stultz: "Re: [patch] clocksource: clean up parse_pmtmr()"
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In reply to: Don Dutile: "Re: [BUG 3.7-rc5] NULL pointer deref when using a pcie-pci bridgedpci device and intel-iommu"
Next in thread: Matthew Thode: "Re: [BUG 3.7-rc5] NULL pointer deref when using a pcie-pci bridgedpci device and intel-iommu"
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