Subject: cxgb3: kernel access of bad area with v2.6.36-6794-g12ba8d1

From: Nishanth Aravamudan <[email-masked]>
Date: Wed, 27 Oct 2010 18:54:07 -0700

Hi,

I'm seeing the following trace w/ current git on a machine in our lab:

Chelsio T3 Network Driver - version 1.1.4-ko
cxgb3 0003:01:00.0: enabling device (0140 -> 0142)
Unable to handle kernel paging request for data at address 0x00000010
Faulting instruction address: 0xd000000008473ae8
Oops: Kernel access of bad area, sig: 11 [#1]
SMP NR_CPUS=32 NUMA pSeries
last sysfs file: /sys/devices/virtual/block/dm-0/dev
Modules linked in: cxgb3(+) mdio ehea ib_ehca ib_core ext4 jbd2 mbcache sd_mod crc_t10dif ipr dm_mod [last unloaded: scsi_wait_scan]
NIP: d000000008473ae8 LR: d000000008473ac4 CTR: c0000000004398a0
REGS: c0000007a157f190 TRAP: 0300   Not tainted  (2.6.36)
MSR: 8000000000009032 <EE,ME,IR,DR>  CR: 24424444  XER: 00000000
DAR: 0000000000000010, DSISR: 0000000040000000
TASK = c0000007a3755290[741] 'modprobe' THREAD: c0000007a157c000 CPU: 24
GPR00: 0000000000000000 c0000007a157f410 d000000008486978 c0000007a526c000 
GPR04: c0000000006d25dd c0000007a526c005 c0000007a526c29e 0000000000000002 
GPR08: 0000000000000004 0000000000000010 c0000007a526c0a0 0000000000000000 
GPR12: d000000008474aa8 c00000000eed3c00 d00000000847aeb8 0000000000000001 
GPR16: 0000000000001000 0000000000000000 d000000008477aa8 00003c047ef7e000 
GPR20: c0000007a8b7d280 c0000007a8b7d310 d00000000847d1c0 d00000000847d1d8 
GPR24: 0000000000000003 00003c047ef7efff 0000000000000001 c0000007a3c1c000 
GPR28: 0000000000000000 c0000007a526c000 d000000008484210 c0000007a3c1c000 
NIP [d000000008473ae8] .init_one+0x510/0xb7c [cxgb3]
LR [d000000008473ac4] .init_one+0x4ec/0xb7c [cxgb3]
Call Trace:
[c0000007a157f410] [d000000008473ac4] .init_one+0x4ec/0xb7c [cxgb3] (unreliable)
[c0000007a157f560] [c0000000002e40bc] .local_pci_probe+0x7c/0x100
[c0000007a157f5f0] [c0000000002e5018] .pci_device_probe+0x148/0x150
[c0000007a157f6a0] [c00000000034df68] .driver_probe_device+0x128/0x330
[c0000007a157f750] [c00000000034e27c] .__driver_attach+0x10c/0x110
[c0000007a157f7e0] [c00000000034d15c] .bus_for_each_dev+0x9c/0xf0
[c0000007a157f890] [c00000000034dbc8] .driver_attach+0x28/0x40
[c0000007a157f910] [c00000000034c648] .bus_add_driver+0x218/0x3d0
[c0000007a157f9c0] [c00000000034e718] .driver_register+0x98/0x1d0
[c0000007a157fa60] [c0000000002e5354] .__pci_register_driver+0x64/0x140
[c0000007a157fb00] [d000000008474278] .cxgb3_init_module+0x2c/0x44 [cxgb3]
[c0000007a157fb80] [c000000000009754] .do_one_initcall+0x64/0x1e0
[c0000007a157fc40] [c0000000000d28b8] .SyS_init_module+0x1b8/0x1790
[c0000007a157fe30] [c000000000008564] syscall_exit+0x0/0x40
Instruction dump:
9b890018 9b090019 48000fe9 e8410028 801d0308 2f800000 419e003c 39600000 
e93d0300 796045e4 7d290214 39290010 <7c0048a8> 7c00d378 7c0049ad 40a2fff4 
---[ end trace 2a530df8c4ad3d70 ]---
udevd-work[600]: '/sbin/modprobe -b pci:v00001425d00000030sv00001014sd0000038Cbc02sc00i00' unexpected exit with status 0x000b

I did an objdump -ldr of cxgb3.ko and:

 4c0:   48 00 00 01     bl      4c0 <.init_one+0x4c0>
                        4c0: R_PPC64_REL24      .alloc_etherdev_mq
 4c4:   60 00 00 00     nop
 4c8:   7c 7d 1b 79     mr.     r29,r3
 4cc:   41 82 03 28     beq-    7f4 <.init_one+0x7f4>
 4d0:   39 3d 07 00     addi    r9,r29,1792
 4d4:   fa bd 03 f8     std     r21,1016(r29)
 4d8:   fb bb 32 08     std     r29,12808(r27)
 4dc:   fb fd 07 00     std     r31,1792(r29)
 4e0:   9b 89 00 18     stb     r28,24(r9)
 4e4:   9b 09 00 19     stb     r24,25(r9)
 4e8:   48 00 00 01     bl      4e8 <.init_one+0x4e8>
                        4e8: R_PPC64_REL24      .netif_carrier_off
 4ec:   60 00 00 00     nop
 4f0:   80 1d 03 08     lwz     r0,776(r29)
 4f4:   2f 80 00 00     cmpwi   cr7,r0,0
 4f8:   41 9e 00 3c     beq-    cr7,534 <.init_one+0x534>
 4fc:   39 60 00 00     li      r11,0
 500:   e9 3d 03 00     ld      r9,768(r29)
 504:   79 60 45 e4     rldicr  r0,r11,8,55
 508:   7d 29 02 14     add     r9,r9,r0
 50c:   39 29 00 10     addi    r9,r9,16
 510:   7c 00 48 a8     ldarx   r0,0,r9
 514:   7c 00 d3 78     or      r0,r0,r26
 518:   7c 00 49 ad     stdcx.  r0,0,r9
 51c:   40 a2 ff f4     bne-    510 <.init_one+0x510>

So I'm guessing it's somewhere in here:

        for (i = 0; i < ai->nports0 + ai->nports1; ++i) {
                struct net_device *netdev;

                netdev = alloc_etherdev_mq(sizeof(struct port_info), SGE_QSETS);
                if (!netdev) {
                        err = -ENOMEM;
                        goto out_free_dev;
                }

                SET_NETDEV_DEV(netdev, &pdev->dev);

                adapter->port[i] = netdev;
                pi = netdev_priv(netdev);
                pi->adapter = adapter;
                pi->rx_offload = T3_RX_CSUM | T3_LRO;
                pi->port_id = i;
                netif_carrier_off(netdev);
                netif_tx_stop_all_queues(netdev);
                netdev->irq = pdev->irq;
                netdev->mem_start = mmio_start;
                netdev->mem_end = mmio_start + mmio_len - 1;
                netdev->features |= NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO;
                netdev->features |= NETIF_F_GRO;
                if (pci_using_dac)
                        netdev->features |= NETIF_F_HIGHDMA;

                netdev->features |= NETIF_F_HW_VLAN_TX | NETIF_F_HW_VLAN_RX;
                netdev->netdev_ops = &cxgb_netdev_ops;
                SET_ETHTOOL_OPS(netdev, &cxgb_ethtool_ops);
        }

Well, presuming the trace is mostly accurate?  I'm not sure what else is
needed to determine the problem further. I'm building 2.6.36 as I write
this.  But it doesn't seem like this code has changed much and I had a
working kernel around 2.6.36-rc7...

Let me know what else I can do to help debug.

Thanks,
Nish

-- 
Nishanth Aravamudan <[email-masked]>
IBM Linux Technology Center