On Mon, Apr 21, 2014 at 10:25:18AM +0800, Wei Yang wrote:
>When pcibios_remove_pci_devices() is removing pci devices, it will release
>pci device respectively. When the refcount of the device is 0, the pci_dev
>structure will be destroyed.
>
>On PowerNV platform, the pci_dev will not be destroyed since the refcount is
>not 0.
>
Richard, the above description is true. However, it's not relevant to the
issue (backtrace). I don't quite understand the scenario you had. You're
doing hotplug on VFs or PF? I guess it would be full-hotplug instead of
partial hotplug.
It seems that the IOMMU group wasn't detached correctly and then we tried
to attach it again. Or the IOMMU group was attached for towice? :-)
The IOMMU group is expected to be detached like this, please investigate
for more why it wasn't detached correctly.
pcibios_remove_pci_devices()
pci_stop_and_remove_bus_device()
pci_remove_bus_device()
pci_destroy_dev()
static void pci_destroy_dev(struct pci_dev *dev)
{
if (!dev->dev.kobj.parent)
return;
device_del(&dev->dev); /* It's calling iommu_del_device()
*/
down_write(&pci_bus_sem);
list_del(&dev->bus_list);
up_write(&pci_bus_sem);
pci_free_resources(dev);
put_device(&dev->dev); /* It's calling
pcibios_release_device() */
}
Thanks,
Gavin
>After applying the patch, this warning is cleared during the EEH hotplug
>event.
>
>[ 204.123609] ------------[ cut here ]------------
>[ 204.123645] WARNING: at arch/powerpc/kernel/iommu.c:1125
>[ 204.123680] Modules linked in: xt_CHECKSUM nf_conntrack_netbios_ns
>nf_conntrack_broadcast ipt_MASQUERADE ip6t_REJECT bnep bluetooth 6lowpan_iphc
>rfkill xt_conntrack ebtable_nat ebtable_broute bridge stp llc mlx4_ib ib_sa
>ib_mad ib_core ib_addr ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6
>nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw
>ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4
>nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw
>bnx2x tg3 mlx4_core nfsd ptp mdio ses libcrc32c nfs_acl enclosure be2net
>pps_core shpchp lockd kvm uinput sunrpc binfmt_misc lpfc scsi_transport_fc ipr
>scsi_tgt
>[ 204.124356] CPU: 18 PID: 650 Comm: eehd Not tainted 3.14.0-rc5yw+ #102
>[ 204.124400] task: c0000027ed485670 ti: c0000027ed50c000 task.ti:
>c0000027ed50c000
>[ 204.124453] NIP: c00000000003cf80 LR: c00000000006c648 CTR: c00000000006c5c0
>[ 204.124506] REGS: c0000027ed50f440 TRAP: 0700 Not tainted (3.14.0-rc5yw+)
>[ 204.124558] MSR: 9000000000029032 <SF,HV,EE,ME,IR,DR,RI> CR: 88008084
>XER: 20000000
>[ 204.124682] CFAR: c00000000006c644 SOFTE: 1
>GPR00: c00000000006c648 c0000027ed50f6c0 c000000001398380 c0000027ec260300
>GPR04: c0000027ea92c000 c00000000006ad00 c0000000016e41b0 0000000000000110
>GPR08: c0000000012cd4c0 0000000000000001 c0000027ec2602ff 0000000000000062
>GPR12: 0000000028008084 c00000000fdca200 c0000000000d1d90 c0000027ec281a80
>GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000001
>GPR24: 000000005342697b 0000000000002906 c000001fe6ac9800 c000001fe6ac9800
>GPR28: 0000000000000000 c0000000016e3a80 c0000027ea92c090 c0000027ea92c000
>[ 204.125353] NIP [c00000000003cf80] .iommu_add_device+0x30/0x1f0
>[ 204.125399] LR [c00000000006c648] .pnv_pci_ioda_dma_dev_setup+0x88/0xb0
>[ 204.125443] Call Trace:
>[ 204.125464] [c0000027ed50f6c0] [c0000027ed50f750] 0xc0000027ed50f750
>(unreliable)
>[ 204.125526] [c0000027ed50f750] [c00000000006c648]
>.pnv_pci_ioda_dma_dev_setup+0x88/0xb0
>[ 204.125588] [c0000027ed50f7d0] [c000000000069cc8]
>.pnv_pci_dma_dev_setup+0x78/0x340
>[ 204.125650] [c0000027ed50f870] [c000000000044408]
>.pcibios_setup_device+0x88/0x2f0
>[ 204.125712] [c0000027ed50f940] [c000000000046040]
>.pcibios_setup_bus_devices+0x60/0xd0
>[ 204.125774] [c0000027ed50f9c0] [c000000000043acc]
>.pcibios_add_pci_devices+0xdc/0x1c0
>[ 204.125837] [c0000027ed50fa50] [c00000000086f970]
>.eeh_reset_device+0x36c/0x4f0
>[ 204.125939] [c0000027ed50fb20] [c00000000003a2d8]
>.eeh_handle_normal_event+0x448/0x480
>[ 204.126068] [c0000027ed50fbc0] [c00000000003a35c]
>.eeh_handle_event+0x4c/0x340
>[ 204.126192] [c0000027ed50fc80] [c00000000003a74c]
>.eeh_event_handler+0xfc/0x1b0
>[ 204.126319] [c0000027ed50fd30] [c0000000000d1ea0] .kthread+0x110/0x130
>[ 204.126430] [c0000027ed50fe30] [c00000000000a460]
>.ret_from_kernel_thread+0x5c/0x7c
>[ 204.126556] Instruction dump:
>[ 204.126610] 7c0802a6 fba1ffe8 fbc1fff0 fbe1fff8 f8010010 f821ff71 7c7e1b78
>60000000
>[ 204.126787] 60000000 e87e0298 3143ffff 7d2a1910 <0b090000> 2fa90000
>40de00c8 ebfe0218
>[ 204.126966] ---[ end trace 6e7aefd80add2973 ]---
>
>This patch clear the step to get reference.
>
>Signed-off-by: Wei Yang <weiy...@linux.vnet.ibm.com>
>---
> arch/powerpc/platforms/powernv/pci-ioda.c | 1 -
> 1 file changed, 1 deletion(-)
>
>diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c
>b/arch/powerpc/platforms/powernv/pci-ioda.c
>index e2270f4..fc4edda 100644
>--- a/arch/powerpc/platforms/powernv/pci-ioda.c
>+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>@@ -561,7 +561,6 @@ static void pnv_ioda_setup_same_PE(struct pci_bus *bus,
>struct pnv_ioda_pe *pe)
> pci_name(dev));
> continue;
> }
>- pci_dev_get(dev);
> pdn->pcidev = dev;
> pdn->pe_number = pe->pe_number;
> pe->dma_weight += pnv_ioda_dma_weight(dev);
>--
>1.7.9.5
>
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