doc/notes.org

   1 * uboot settings
   2
   3  set ipaddr 192.168.2.3
   4  set netmask 255.255.255.0
   5  set serverip 192.168.2.2
   6  set imagefile ryu/uImage
   7  set devicetreefile ryu/shark-ryu.dtb
   8  set nfspath /srv/nfs/root-shark
   9  set bootcmd_tftpnfs_static 'tftp 800000 ${imagefile}; tftp 7f0000 ${devicetreefile}; set bootargs ${linux_console} root=/dev/nfs nfsroot=${serverip}:${nfspath} rw ip=${ipaddr}; mw f0000b00 ${psc_cfg}; bootm 800000 - 7f0000'
  10  set bootcmd 'run bootcmd_tftpnfs_static'
  11
  12 * Questions
  13 ** Why crc modification alone does not produce an error and is not returned by cangw -L?
  14 ** Why two simultaneous latesters return ENOBUFS even if txqueue is set high?
  15 latester -d can0
  16 latester -d can1
  17 * Kernel oops
  18 ** Linux-2.6.33.7-00005-ge2f49b5
  19 Unable to handle kernel paging request for instruction fetch
  20 Faulting instruction address: 0x8d56acc4
  21 Oops: Kernel access of bad area, sig: 11 [#1]
  22 PREEMPT Shark
  23 Modules linked in:
  24 NIP: 8d56acc4 LR: c0260208 CTR: 8d56acc7
  25 REGS: c03f3bc0 TRAP: 0400   Not tainted  (2.6.33.7-00005-ge2f49b5)
  26 MSR: 20009032 <EE,ME,IR,DR>  CR: 24008028  XER: 0000005f
  27 TASK = c03d5478[0] 'swapper' THREAD: c03f2000
  28 GPR00: 8d56acc7 c03f3c70 c03d5478 c7990160 c78d54ad 00000048 c79901a4 00000002
  29 GPR08: 000000e0 00000000 00000001 00000002 44000022 7f33ff4e 80000000 00000042
  30 GPR16: 00000008 20000000 c909e900 00000001 c03f3d78 c79326e0 00000008 c799dc1c
  31 GPR24: c7976800 c78d54f9 c7949828 c7a06620 c03f2000 c7990160 c78d54ad c03f3c70
  32 NIP [8d56acc4] 0x8d56acc4
  33 LR [c0260208] dev_queue_xmit+0x2f0/0x588
  34 Call Trace:
  35 [c03f3c70] [c025ff74] dev_queue_xmit+0x5c/0x588 (unreliable)
  36 [c03f3ca0] [c02d62d8] can_send+0x9c/0x1a0
  37 [c03f3cc0] [c02d97a8] can_can_gw_rcv+0x108/0x164
  38 [c03f3cf0] [c02d52ac] can_rcv_filter+0x240/0x2e8
  39 [c03f3d10] [c02d541c] can_rcv+0xc8/0x140
  40 [c03f3d30] [c025e968] netif_receive_skb+0x2ac/0x350
  41 [c03f3d70] [c020a230] mscan_rx_poll+0x1c0/0x464
  42 [c03f3dd0] [c025f428] net_rx_action+0x104/0x22c
  43 [c03f3e20] [c00345e0] __do_softirq+0x10c/0x21c
  44 [c03f3e70] [c00075d0] do_softirq+0x58/0x74
  45 [c03f3e80] [c0034300] irq_exit+0x8c/0xbc
  46 [c03f3e90] [c00076c8] do_IRQ+0xdc/0x188
  47 [c03f3ec0] [c0014db0] ret_from_except+0x0/0x14
  48 --- Exception: 501 at cpu_idle+0x104/0x114
  49     LR = cpu_idle+0x104/0x114
  50 [c03f3f80] [c000aefc] cpu_idle+0x68/0x114 (unreliable)
  51 [c03f3fa0] [c0003f40] rest_init+0xa4/0xc4
  52 [c03f3fc0] [c039f918] start_kernel+0x2e4/0x2fc
  53 [c03f3ff0] [00003438] 0x3438
  54 Instruction dump:
  55 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
  56 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
  57 Kernel panic - not syncing: Fatal exception in interrupt
  58 Call Trace:
  59 [c03f3ab0] [c0009cdc] show_stack+0x70/0x1d4 (unreliable)
  60 [c03f3b00] [c02ff5ec] dump_stack+0x2c/0x44
  61 [c03f3b10] [c02ff6b0] panic+0xac/0x19c
  62 [c03f3b60] [c0011df8] die+0x188/0x1a4
  63 [c03f3b90] [c00165c8] bad_page_fault+0x90/0xe0
  64 [c03f3bb0] [c0014bb8] handle_page_fault+0x7c/0x80
  65 --- Exception: 400 at 0x8d56acc4
  66     LR = dev_queue_xmit+0x2f0/0x588
  67 [c03f3c70] [c025ff74] dev_queue_xmit+0x5c/0x588 (unreliable)
  68 [c03f3ca0] [c02d62d8] can_send+0x9c/0x1a0
  69 [c03f3cc0] [c02d97a8] can_can_gw_rcv+0x108/0x164
  70 [c03f3cf0] [c02d52ac] can_rcv_filter+0x240/0x2e8
  71 [c03f3d10] [c02d541c] can_rcv+0xc8/0x140
  72 [c03f3d30] [c025e968] netif_receive_skb+0x2ac/0x350
  73 [c03f3d70] [c020a230] mscan_rx_poll+0x1c0/0x464
  74 [c03f3dd0] [c025f428] net_rx_action+0x104/0x22c
  75 [c03f3e20] [c00345e0] __do_softirq+0x10c/0x21c
  76 [c03f3e70] [c00075d0] do_softirq+0x58/0x74
  77 [c03f3e80] [c0034300] irq_exit+0x8c/0xbc
  78 [c03f3e90] [c00076c8] do_IRQ+0xdc/0x188
  79 [c03f3ec0] [c0014db0] ret_from_except+0x0/0x14
  80 --- Exception: 501 at cpu_idle+0x104/0x114
  81     LR = cpu_idle+0x104/0x114
  82 [c03f3f80] [c000aefc] cpu_idle+0x68/0x114 (unreliable)
  83 [c03f3fa0] [c0003f40] rest_init+0xa4/0xc4
  84 [c03f3fc0] [c039f918] start_kernel+0x2e4/0x2fc
  85 [c03f3ff0] [00003438] 0x3438
  86 Rebooting in 180 seconds..
  87
  88 ** Current kernel
  89 *** Panic
  90 Unable to handle kernel paging request for instruction fetch
  91 Faulting instruction address: 0x8cd6acc4
  92 Oops: Kernel access of bad area, sig: 11 [#1]
  93 PREEMPT Shark
  94 Modules linked in:
  95 NIP: 8cd6acc4 LR: c025fdac CTR: 8cd6acc7
  96 REGS: c03f3bd0 TRAP: 0400   Not tainted  (2.6.33.7-00005-ge2f49b5)
  97 MSR: 20009032 <EE,ME,IR,DR>  CR: 22008028  XER: 0000005f
  98 TASK = c03d6478[0] 'swapper' THREAD: c03f2000
  99 GPR00: 8cd6acc7 c03f3c80 c03d6478 c79fec00 c78cd4ad 00000048 c79fec44 00000002
 100 GPR08: 000000e0 00000000 00000001 c03f3c80 42000022 7f33ff4e 80000000 00000042
 101 GPR16: 00000008 20000000 c909e900 00000001 c03f3d88 c79386e0 00000008 c79fe51c
 102 GPR24: 0000000c c78cd4f9 c7975800 c7949828 c7a33d24 c79fec00 c78cd4ad c03f3c80
 103 NIP [8cd6acc4] 0x8cd6acc4
 104 LR [c025fdac] dev_queue_xmit+0xec/0x588
 105 Call Trace:
 106 [c03f3c80] [c025fd68] dev_queue_xmit+0xa8/0x588 (unreliable)
 107 [c03f3cb0] [c02d5128] can_send+0x9c/0x1a0
 108 [c03f3cd0] [c02d85ec] can_can_gw_rcv+0x108/0x164
 109 [c03f3d00] [c02d3fdc] can_rcv_filter+0xf8/0x2e8
 110 [c03f3d20] [c02d4294] can_rcv+0xc8/0x140
 111 [c03f3d40] [c025e6f8] netif_receive_skb+0x2a8/0x34c
 112 [c03f3d80] [c020a774] mscan_rx_poll+0x1c0/0x464
 113 [c03f3de0] [c025f1b8] net_rx_action+0x104/0x238
 114 [c03f3e30] [c00368c8] __do_softirq+0x128/0x244
 115 [c03f3e80] [c00075e0] do_softirq+0x64/0x80
 116 [c03f3e90] [c00365d0] irq_exit+0x98/0xc4
 117 [c03f3ea0] [c00076d8] do_IRQ+0xdc/0x188
 118 [c03f3ed0] [c0014d40] ret_from_except+0x0/0x14
 119 [c03f3f90] [c000aed8] cpu_idle+0x68/0x10c (unreliable)
 120 --- Exception: 501 at cpu_idle+0xfc/0x10c
 121     LR = cpu_idle+0xfc/0x10c
 122 [c03f3fb0] [c0003f34] rest_init+0x98/0xc4
 123 [c03f3fc0] [c039f914] start_kernel+0x2e0/0x2f8
 124 [c03f3ff0] [00003438] 0x3438
 125 Instruction dump:
 126 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
 127 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
 128 Kernel panic - not syncing: Fatal exception in interrupt
 129 Call Trace:
 130 [c03f3ac0] [c0009cc0] show_stack+0x70/0x1d4 (unreliable)
 131 [c03f3b10] [c02fde74] dump_stack+0x2c/0x44
 132 [c03f3b20] [c02fdf30] panic+0xa4/0x19c
 133 [c03f3b70] [c0011d90] die+0x184/0x1a0
 134 --- Exception: c03f3d88 at 0x42000022
 135     LR = 0x8
 136 [c03f3ba0] [c0016558] bad_page_fault+0x90/0xe0 (unreliable)
 137 [c03f3bc0] [c0014b48] handle_page_fault+0x7c/0x80
 138 --- Exception: 400 at 0x8cd6acc4
 139     LR = dev_queue_xmit+0xec/0x588
 140 [c03f3c80] [c025fd68] dev_queue_xmit+0xa8/0x588 (unreliable)
 141 [c03f3cb0] [c02d5128] can_send+0x9c/0x1a0
 142 [c03f3cd0] [c02d85ec] can_can_gw_rcv+0x108/0x164
 143 [c03f3d00] [c02d3fdc] can_rcv_filter+0xf8/0x2e8
 144 [c03f3d20] [c02d4294] can_rcv+0xc8/0x140
 145 [c03f3d40] [c025e6f8] netif_receive_skb+0x2a8/0x34c
 146 [c03f3d80] [c020a774] mscan_rx_poll+0x1c0/0x464
 147 [c03f3de0] [c025f1b8] net_rx_action+0x104/0x238
 148 [c03f3e30] [c00368c8] __do_softirq+0x128/0x244
 149 [c03f3e80] [c00075e0] do_softirq+0x64/0x80
 150 [c03f3e90] [c00365d0] irq_exit+0x98/0xc4
 151 [c03f3ea0] [c00076d8] do_IRQ+0xdc/0x188
 152 [c03f3ed0] [c0014d40] ret_from_except+0x0/0x14
 153 --- Exception: 501 at cpu_idle+0xfc/0x10c
 154     LR = cpu_idle+0xfc/0x10c
 155 [c03f3f90] [c000aed8] cpu_idle+0x68/0x10c (unreliable)
 156 [c03f3fb0] [c0003f34] rest_init+0x98/0xc4
 157 [c03f3fc0] [c039f914] start_kernel+0x2e0/0x2f8
 158 [c03f3ff0] [00003438] 0x3438
 159
 160 *** Disassemble
 161         if (q->enqueue) {
 162 c025fd54:       80 1e 00 00     lwz     r0,0(r30)
 163 c025fd58:       2f 80 00 00     cmpwi   cr7,r0,0
 164 c025fd5c:       41 9e 01 94     beq-    cr7,c025fef0 <dev_queue_xmit+0x230>
 165         raw_spin_lock_init(&(_lock)->rlock);            \
 166 } while (0)
 167
 168 static inline void spin_lock(spinlock_t *lock)
 169 {
 170         raw_spin_lock(&lock->rlock);
 171 c025fd60:       38 60 00 01     li      r3,1
 172 c025fd64:       4b dc 47 cd     bl      c0024530 <add_preempt_count>
 173 c025fd68:       80 1e 00 4c     lwz     r0,76(r30) !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 174 {
 175         spinlock_t *root_lock = qdisc_lock(q);
 176         int rc;
 177
 178         spin_lock(root_lock);
 179         if (unlikely(test_bit(__QDISC_STATE_DEACTIVATED, &q->state))) {
 180 c025fd6c:       3b 3e 00 4c     addi    r25,r30,76
 181 c025fd70:       70 09 00 04     andi.   r9,r0,4
 182 c025fd74:       40 82 01 f0     bne-    c025ff64 <dev_queue_xmit+0x2a4>
 183
 184 *** Corresponding C code
 185 static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
 186                                  struct net_device *dev,
 187                                  struct netdev_queue *txq)
 188 {
 189         spinlock_t *root_lock = qdisc_lock(q);
 190         int rc;
 191
 192         spin_lock(root_lock);
 193
 194 ** 2.6.36.1-00006-g2e11adb
 195 Unable to handle kernel paging request for data at address 0xfffffffe
 196 Faulting instruction address: 0xc0262358
 197 Oops: Kernel access of bad area, sig: 11 [#1]
 198 PREEMPT Shark
 199 last sysfs file: /sys/devices/lpb.0/fc000000.flash/mtd/mtd2ro/dev
 200 Modules linked in:
 201 NIP: c0262358 LR: c026218c CTR: 00000000
 202 REGS: c7ffbd20 TRAP: 0300   Not tainted  (2.6.36.1-00006-g2e11adb)
 203 MSR: 00009032 <EE,ME,IR,DR>  CR: 42008024  XER: 0000005f
 204 DAR: fffffffe, DSISR: 20000000
 205 TASK = c03e44d0[0] 'swapper' THREAD: c0400000
 206 GPR00: c7939560 c7ffbdd0 c03e44d0 00000100 00000000 00000060 c798bb64 00000000
 207 GPR08: 000000e8 00000002 00000001 00000002 42000022 7f33ff4e 80000000 00000042
 208 GPR16: 00000008 20000000 c909e900 00000001 c7ffbef8 c0404a84 c0404a80 c78b4000
 209 GPR24: 00000000 c798bb20 c79395c0 c7a77e20 c796f800 c798bb20 fffffffe c7ffbdd0
 210 NIP [c0262358] dev_queue_xmit+0x200/0x4f0
 211 LR [c026218c] dev_queue_xmit+0x34/0x4f0
 212 Call Trace:
 213 [c7ffbdd0] [c026218c] dev_queue_xmit+0x34/0x4f0 (unreliable)
 214 [c7ffbe00] [c02dd1f4] can_send+0x9c/0x1a0
 215 [c7ffbe20] [c02e07a8] can_can_gw_rcv+0x108/0x164
 216 [c7ffbe50] [c02dc224] can_rcv_filter+0xf8/0x2e8
 217 [c7ffbe70] [c02dc4dc] can_rcv+0xc8/0x140
 218 [c7ffbe90] [c02606f0] __netif_receive_skb+0x2cc/0x338
 219 [c7ffbed0] [c0260934] netif_receive_skb+0x5c/0x98
 220 [c7ffbef0] [c020d72c] mscan_rx_poll+0x1c0/0x454
 221 [c7ffbf50] [c0260c64] net_rx_action+0x104/0x230
 222 [c7ffbfa0] [c0031350] __do_softirq+0x118/0x22c
 223 [c7ffbff0] [c0011704] call_do_softirq+0x14/0x24
 224 [c0401e60] [c0006bdc] do_softirq+0x84/0xa8
 225 [c0401e80] [c0031074] irq_exit+0x88/0xb4
 226 [c0401e90] [c0006d60] do_IRQ+0xe0/0x234
 227 [c0401ec0] [c00123d4] ret_from_except+0x0/0x14
 228 --- Exception: 501 at cpu_idle+0xfc/0x10c
 229     LR = cpu_idle+0xfc/0x10c
 230 [c0401f80] [c000a7a8] cpu_idle+0x68/0x10c (unreliable)
 231 [c0401fa0] [c0003ec0] rest_init+0x9c/0xbc
 232 [c0401fc0] [c03ad91c] start_kernel+0x2c0/0x2d8
 233 [c0401ff0] [00003438] 0x3438
 234 Instruction dump:
 235 41920198 817e000c 2f8b0000 419c018c 55693032 55602036 7ca04850 5569043e
 236 b13d0074 801c01c8 7f402a14 83da0004 <801e0000> 2f800000 409efe88 801c00d8
 237 Kernel panic - not syncing: Fatal exception in interrupt
 238 Call Trace:
 239 [c7ffbc00] [c00095dc] show_stack+0xb0/0x1d4 (unreliable)
 240 [c7ffbc50] [c030664c] dump_stack+0x2c/0x44
 241 [c7ffbc60] [c0306720] panic+0xbc/0x1fc
 242 [c7ffbcc0] [c000f34c] die+0x1b8/0x1e8
 243 --- Exception: c7ffbef8 at 0x42000022
 244     LR = 0x8
 245 [c7ffbcf0] [c0013b8c] bad_page_fault+0x90/0xe0 (unreliable)
 246 [c7ffbd10] [c00121dc] handle_page_fault+0x7c/0x80
 247 --- Exception: 300 at dev_queue_xmit+0x200/0x4f0
 248     LR = dev_queue_xmit+0x34/0x4f0
 249 [c7ffbe00] [c02dd1f4] can_send+0x9c/0x1a0
 250 [c7ffbe20] [c02e07a8] can_can_gw_rcv+0x108/0x164
 251 [c7ffbe50] [c02dc224] can_rcv_filter+0xf8/0x2e8
 252 [c7ffbe70] [c02dc4dc] can_rcv+0xc8/0x140
 253 [c7ffbe90] [c02606f0] __netif_receive_skb+0x2cc/0x338
 254 [c7ffbed0] [c0260934] netif_receive_skb+0x5c/0x98
 255 [c7ffbef0] [c020d72c] mscan_rx_poll+0x1c0/0x454
 256 [c7ffbf50] [c0260c64] net_rx_action+0x104/0x230
 257 [c7ffbfa0] [c0031350] __do_softirq+0x118/0x22c
 258 [c7ffbff0] [c0011704] call_do_softirq+0x14/0x24
 259 [c0401e60] [c0006bdc] do_softirq+0x84/0xa8
 260 [c0401e80] [c0031074] irq_exit+0x88/0xb4
 261 [c0401e90] [c0006d60] do_IRQ+0xe0/0x234
 262 [c0401ec0] [c00123d4] ret_from_except+0x0/0x14
 263 --- Exception: 501 at cpu_idle+0xfc/0x10c
 264     LR = cpu_idle+0xfc/0x10c
 265 [c0401f80] [c000a7a8] cpu_idle+0x68/0x10c (unreliable)
 266 [c0401fa0] [c0003ec0] rest_init+0x9c/0xbc
 267 [c0401fc0] [c03ad91c] start_kernel+0x2c0/0x2d8
 268 [c0401ff0] [00003438] 0x3438
 269
 270 ** With "Spinlock and rw-lock debugging: basic checks"
 271 BUG: spinlock bad magic on CPU#0, swapper/0
 272  lock: c7985abc, .magic: c0000000, .owner: <none>/-1, .owner_cpu: -1069448776
 273
 274 *** later
 275 BUG: spinlock bad magic on CPU#0, swapper/0
 276  lock: c798cabc, .magic: c0000000, .owner: <none>/-1, .owner_cpu: -1069337880
 277 Call Trace:
 278 [c7ffbd00] [c000a090] show_stack+0xb0/0x1d4 (unreliable)
 279 [c7ffbd50] [c031157c] dump_stack+0x2c/0x44
 280 [c7ffbd60] [c01c0914] spin_bug+0x84/0xd0
 281 [c7ffbd80] [c01c0ac0] do_raw_spin_lock+0x3c/0x15c
 282 [c7ffbdb0] [c0310e34] _raw_spin_lock+0x34/0x4c
 283 [c7ffbdd0] [c026d170] dev_queue_xmit+0xa4/0x428
 284 [c7ffbe00] [c02e7a28] can_send+0x9c/0x1a0
 285 [c7ffbe20] [c02eb038] can_can_gw_rcv+0x108/0x164
 286 [c7ffbe50] [c02e6c18] can_rcv_filter+0x240/0x2e8
 287 [c7ffbe70] [c02e6d88] can_rcv+0xc8/0x140
 288 [c7ffbe90] [c026b664] __netif_receive_skb+0x2cc/0x338
 289 [c7ffbed0] [c026b8a8] netif_receive_skb+0x5c/0x98
 290 [c7ffbef0] [c0219908] mscan_rx_poll+0x1c0/0x454
 291 [c7ffbf50] [c026bbd8] net_rx_action+0x104/0x230
 292 [c7ffbfa0] [c00356a4] __do_softirq+0x118/0x22c
 293 [c7ffbff0] [c00126b4] call_do_softirq+0x14/0x24
 294 [c0445e60] [c00070b8] do_softirq+0x84/0xa8
 295 [c0445e80] [c00354e0] irq_exit+0x88/0xb4
 296 [c0445e90] [c00071bc] do_IRQ+0xe0/0x234
 297 [c0445ec0] [c0013384] ret_from_except+0x0/0x14
 298 --- Exception: 501 at cpu_idle+0xfc/0x10c
 299     LR = cpu_idle+0xfc/0x10c
 300 [c0445f80] [c000b444] cpu_idle+0x68/0x10c (unreliable)
 301 [c0445fa0] [c0003ec0] rest_init+0x9c/0xbc
 302 [c0445fc0] [c03ed91c] start_kernel+0x2c0/0x2d8
 303 [c0445ff0] [00003438] 0x3438
 304
 305 ** With "Spinlock debugging: sleep-inside-spinlock checking"
 306 BUG: sleeping function called from invalid context at /home/wsh/projects/can-benchmark/kernel/2.6.36/mm/slab.c:3101
 307 in_atomic(): 1, irqs_disabled(): 0, pid: 379, name: cangw
 308 Call Trace:
 309 [c7abdb50] [c0009c04] show_stack+0xb0/0x1d4 (unreliable)
 310 [c7abdba0] [c02ffe54] dump_stack+0x2c/0x44
 311 [c7abdbb0] [c002157c] __might_sleep+0xfc/0x124
 312 [c7abdbc0] [c00c45bc] kmem_cache_alloc+0x15c/0x180
 313 [c7abdbf0] [c02d60d8] can_rx_register+0x78/0x210
 314 [c7abdc30] [c02d9ebc] cgw_create_job+0x1cc/0x220
 315 [c7abdc50] [c026c208] rtnetlink_rcv_msg+0x21c/0x28c
 316 [c7abdc70] [c02762a4] netlink_rcv_skb+0xb8/0x100
 317 [c7abdc90] [c026bfd0] rtnetlink_rcv+0x40/0x5c
 318 [c7abdcb0] [c0275e9c] netlink_unicast+0x320/0x368
 319 [c7abdd00] [c0276a0c] netlink_sendmsg+0x2e0/0x33c
 320 [c7abdd50] [c0244cc0] sock_sendmsg+0x9c/0xd4
 321 [c7abde20] [c0247194] sys_sendto+0xcc/0x108
 322 [c7abdf00] [c0248980] sys_socketcall+0x17c/0x218
 323 [c7abdf40] [c0012524] ret_from_syscall+0x0/0x38
 324 --- Exception: c01 at 0xff3413c
 325     LR = 0x10001f9c
 326 BUG: spinlock bad magic on CPU#0, swapper/0
 327  lock: c798aabc, .magic: c0000000, .owner: <none>/-1, .owner_cpu: -1069424200
 328 Call Trace:
 329 [c7ffbd00] [c0009c04] show_stack+0xb0/0x1d4 (unreliable)
 330 [c7ffbd50] [c02ffe54] dump_stack+0x2c/0x44
 331 [c7ffbd60] [c01afa50] spin_bug+0x84/0xd0
 332 [c7ffbd80] [c01afbfc] do_raw_spin_lock+0x3c/0x15c
 333 [c7ffbdb0] [c02ff70c] _raw_spin_lock+0x34/0x4c
 334 [c7ffbdd0] [c025bbdc] dev_queue_xmit+0xa4/0x428
 335 [c7ffbe00] [c02d630c] can_send+0x9c/0x1a0
 336 [c7ffbe20] [c02d991c] can_can_gw_rcv+0x108/0x164
 337 [c7ffbe50] [c02d53b4] can_rcv_filter+0xf8/0x2e8
 338 [c7ffbe70] [c02d566c] can_rcv+0xc8/0x140
 339 [c7ffbe90] [c025a0d0] __netif_receive_skb+0x2cc/0x338
 340 [c7ffbed0] [c025a314] netif_receive_skb+0x5c/0x98
 341 [c7ffbef0] [c0208374] mscan_rx_poll+0x1c0/0x454
 342 [c7ffbf50] [c025a644] net_rx_action+0x104/0x230
 343 [c7ffbfa0] [c00317a8] __do_softirq+0x118/0x22c
 344 [c7ffbff0] [c0011eec] call_do_softirq+0x14/0x24
 345 [c042fe60] [c0006d78] do_softirq+0x84/0xa8
 346 [c042fe80] [c00314cc] irq_exit+0x88/0xb4
 347 [c042fe90] [c0006efc] do_IRQ+0xe0/0x234
 348 [c042fec0] [c0012bbc] ret_from_except+0x0/0x14
 349 --- Exception: 501 at cpu_idle+0xfc/0x10c
 350     LR = cpu_idle+0xfc/0x10c
 351 [c042ff80] [c000afb8] cpu_idle+0x68/0x10c (unreliable)
 352 [c042ffa0] [c0003ec0] rest_init+0x9c/0xbc
 353 [c042ffc0] [c03da91c] start_kernel+0x2c0/0x2d8
 354 [c042fff0] [00003438] 0x3438
 355 ** First patch
 356 diff --git a/net/can/gw.c b/net/can/gw.c
 357 index 94ba3f1..7779ca6 100644
 358 --- a/net/can/gw.c
 359 +++ b/net/can/gw.c
 360 @@ -822,11 +822,14 @@ static int cgw_create_job(struct sk_buff *skb,  struct nlmsghdr *nlh,
 361         if (gwj->dst.dev->type != ARPHRD_CAN)
 362                 goto put_src_dst_out;
 363
 364 -       spin_lock(&cgw_list_lock);
 365
 366         err = cgw_register_filter(gwj);
 367 -       if (!err)
 368 -               hlist_add_head_rcu(&gwj->list, &cgw_list);
 369 +       if (err)
 370 +               goto put_src_dst_out;
 371 +
 372 +       spin_lock(&cgw_list_lock);
 373 +
 374 +       hlist_add_head_rcu(&gwj->list, &cgw_list);
 375
 376         spin_unlock(&cgw_list_lock);
 377
 378 ** GFP_ATOMIC patch
 379 diff --git a/net/can/af_can.c b/net/can/af_can.c
 380 index 702be5a..b046ff0 100644
 381 --- a/net/can/af_can.c
 382 +++ b/net/can/af_can.c
 383 @@ -418,7 +418,7 @@ int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask,
 384         if (dev && dev->type != ARPHRD_CAN)
 385                 return -ENODEV;
 386
 387 -       r = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
 388 +       r = kmem_cache_alloc(rcv_cache, GFP_ATOMIC);
 389         if (!r)
 390                 return -ENOMEM;
 391
 392 ** Another panic
 393 BUG: spinlock bad magic on CPU#0, swapper/0
 394  lock: c7986abc, .magic: c0000000, .owner: <none>/-1, .owner_cpu: -1069424200
 395 Call Trace:
 396 [c7ffbd00] [c0009c04] show_stack+0xb0/0x1d4 (unreliable)
 397 [c7ffbd50] [c02ffe54] dump_stack+0x2c/0x44
 398 [c7ffbd60] [c01afa50] spin_bug+0x84/0xd0
 399 [c7ffbd80] [c01afbfc] do_raw_spin_lock+0x3c/0x15c
 400 [c7ffbdb0] [c02ff70c] _raw_spin_lock+0x34/0x4c
 401 [c7ffbdd0] [c025bbdc] dev_queue_xmit+0xa4/0x428
 402 [c7ffbe00] [c02d630c] can_send+0x9c/0x1a0
 403 [c7ffbe20] [c02d991c] can_can_gw_rcv+0x108/0x164
 404 [c7ffbe50] [c02d53b4] can_rcv_filter+0xf8/0x2e8
 405 [c7ffbe70] [c02d566c] can_rcv+0xc8/0x140
 406 [c7ffbe90] [c025a0d0] __netif_receive_skb+0x2cc/0x338
 407 [c7ffbed0] [c025a314] netif_receive_skb+0x5c/0x98
 408 [c7ffbef0] [c0208374] mscan_rx_poll+0x1c0/0x454
 409 [c7ffbf50] [c025a644] net_rx_action+0x104/0x230
 410 [c7ffbfa0] [c00317a8] __do_softirq+0x118/0x22c
 411 [c7ffbff0] [c0011eec] call_do_softirq+0x14/0x24
 412 [c042fe60] [c0006d78] do_softirq+0x84/0xa8
 413 [c042fe80] [c00314cc] irq_exit+0x88/0xb4
 414 [c042fe90] [c0006efc] do_IRQ+0xe0/0x234
 415 [c042fec0] [c0012bbc] ret_from_except+0x0/0x14
 416 --- Exception: 501 at cpu_idle+0xfc/0x10c
 417     LR = cpu_idle+0xfc/0x10c
 418 [c042ff80] [c000afb8] cpu_idle+0x68/0x10c (unreliable)
 419 [c042ffa0] [c0003ec0] rest_init+0x9c/0xbc
 420 [c042ffc0] [c03da91c] start_kernel+0x2c0/0x2d8
 421 [c042fff0] [00003438] 0x3438
 422 Unrecoverable FP Unavailable Exception 801 at c7986ca0
 423 Oops: Unrecoverable FP Unavailable Exception, sig: 6 [#1]
 424 PREEMPT Shark
 425 last sysfs file: /sys/devices/lpb.0/fc000000.flash/mtd/mtd2ro/dev
 426 Modules linked in:
 427 NIP: c7986ca0 LR: c025bc3c CTR: c7986ca0
 428 REGS: c7ffbd20 TRAP: 0801   Not tainted  (2.6.36.1-00006-g2e11adb-dirty)
 429 MSR: 00009032 <EE,ME,IR,DR>  CR: 22002024  XER: 2000005f
 430 TASK = c0411520[0] 'swapper' THREAD: c042e000
 431 GPR00: c7986ca0 c7ffbdd0 c0411520 c79b8240 c7986a60 00000010 c043b384 00004000
 432 GPR08: c043b788 00000000 00003fff c7ffbdd0 42002024
 433 NIP [c7986ca0] 0xc7986ca0
 434 LR [c025bc3c] dev_queue_xmit+0x104/0x428
 435 Call Trace:
 436 [c7ffbdd0] [c025bbdc] dev_queue_xmit+0xa4/0x428 (unreliable)
 437 [c7ffbe00] [c02d630c] can_send+0x9c/0x1a0
 438 [c7ffbe20] [c02d991c] can_can_gw_rcv+0x108/0x164
 439 [c7ffbe50] [c02d53b4] can_rcv_filter+0xf8/0x2e8
 440 [c7ffbe70] [c02d566c] can_rcv+0xc8/0x140
 441 [c7ffbe90] [c025a0d0] __netif_receive_skb+0x2cc/0x338
 442 [c7ffbed0] [c025a314] netif_receive_skb+0x5c/0x98
 443 [c7ffbef0] [c0208374] mscan_rx_poll+0x1c0/0x454
 444 [c7ffbf50] [c025a644] net_rx_action+0x104/0x230
 445 [c7ffbfa0] [c00317a8] __do_softirq+0x118/0x22c
 446 [c7ffbff0] [c0011eec] call_do_softirq+0x14/0x24
 447 [c042fe60] [c0006d78] do_softirq+0x84/0xa8
 448 [c042fe80] [c00314cc] irq_exit+0x88/0xb4
 449 [c042fe90] [c0006efc] do_IRQ+0xe0/0x234
 450 [c042fec0] [c0012bbc] ret_from_except+0x0/0x14
 451 --- Exception: 501 at cpu_idle+0xfc/0x10c
 452     LR = cpu_idle+0xfc/0x10c
 453 [c042ff80] [c000afb8] cpu_idle+0x68/0x10c (unreliable)
 454 [c042ffa0] [c0003ec0] rest_init+0x9c/0xbc
 455 [c042ffc0] [c03da91c] start_kernel+0x2c0/0x2d8
 456 [c042fff0] [00003438] 0x3438
 457 Instruction dump:
 458 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
 459 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
 460 Kernel panic - not syncing: Fatal exception in interrupt
 461 Call Trace:
 462 [c7ffbc10] [c0009c04] show_stack+0xb0/0x1d4 (unreliable)
 463 [c7ffbc60] [c02ffe54] dump_stack+0x2c/0x44
 464 [c7ffbc70] [c02fff28] panic+0xbc/0x200
 465 [c7ffbcd0] [c000faf8] die+0x1a4/0x1cc
 466 [c7ffbcf0] [c000fc34] kernel_fp_unavailable_exception+0x4c/0x64
 467 [c7ffbd10] [c0012bbc] ret_from_except+0x0/0x14
 468 --- Exception: 801 at 0xc7986ca0
 469     LR = dev_queue_xmit+0x104/0x428
 470 [c7ffbdd0] [c025bbdc] dev_queue_xmit+0xa4/0x428 (unreliable)
 471 [c7ffbe00] [c02d630c] can_send+0x9c/0x1a0
 472 [c7ffbe20] [c02d991c] can_can_gw_rcv+0x108/0x164
 473 [c7ffbe50] [c02d53b4] can_rcv_filter+0xf8/0x2e8
 474 [c7ffbe70] [c02d566c] can_rcv+0xc8/0x140
 475 [c7ffbe90] [c025a0d0] __netif_receive_skb+0x2cc/0x338
 476 [c7ffbed0] [c025a314] netif_receive_skb+0x5c/0x98
 477 [c7ffbef0] [c0208374] mscan_rx_poll+0x1c0/0x454
 478 [c7ffbf50] [c025a644] net_rx_action+0x104/0x230
 479 [c7ffbfa0] [c00317a8] __do_softirq+0x118/0x22c
 480 [c7ffbff0] [c0011eec] call_do_softirq+0x14/0x24
 481 [c042fe60] [c0006d78] do_softirq+0x84/0xa8
 482 [c042fe80] [c00314cc] irq_exit+0x88/0xb4
 483 [c042fe90] [c0006efc] do_IRQ+0xe0/0x234
 484 [c042fec0] [c0012bbc] ret_from_except+0x0/0x14
 485 --- Exception: 501 at cpu_idle+0xfc/0x10c
 486     LR = cpu_idle+0xfc/0x10c
 487 [c042ff80] [c000afb8] cpu_idle+0x68/0x10c (unreliable)
 488 [c042ffa0] [c0003ec0] rest_init+0x9c/0xbc
 489 [c042ffc0] [c03da91c] start_kernel+0x2c0/0x2d8
 490 [c042fff0] [00003438] 0x3438
 491
 492 ** After cansend can1
 493 BUG: spinlock bad magic on CPU#0, swapper/0
 494  lock: c7985abc, .magic: c0000000, .owner: <none>/-1, .owner_cpu: -1069424200
 495 Call Trace:
 496 [c7ffbd00] [c0009c04] show_stack+0xb0/0x1d4 (unreliable)
 497 [c7ffbd50] [c0300434] dump_stack+0x2c/0x44
 498 [c7ffbd60] [c01afa50] spin_bug+0x84/0xd0
 499 [c7ffbd80] [c01afbfc] do_raw_spin_lock+0x3c/0x15c
 500 [c7ffbdb0] [c02ffcec] _raw_spin_lock+0x34/0x4c
 501 [c7ffbdd0] [c025c1a0] dev_queue_xmit+0xa4/0x428
 502 [c7ffbe00] [c02d68d0] can_send+0x9c/0x1a0
 503 [c7ffbe20] [c02da27c] can_can_gw_rcv+0x108/0x164
 504 [c7ffbe50] [c02d5978] can_rcv_filter+0xf8/0x2e8
 505 [c7ffbe70] [c02d5c30] can_rcv+0xc8/0x140
 506 [c7ffbe90] [c025a694] __netif_receive_skb+0x2cc/0x338
 507 [c7ffbed0] [c025a8d8] netif_receive_skb+0x5c/0x98
 508 [c7ffbef0] [c0208938] mscan_rx_poll+0x1c0/0x454
 509 [c7ffbf50] [c025ac08] net_rx_action+0x104/0x230
 510 [c7ffbfa0] [c00317a8] __do_softirq+0x118/0x22c
 511 [c7ffbff0] [c0011eec] call_do_softirq+0x14/0x24
 512 [c042fe60] [c0006d78] do_softirq+0x84/0xa8
 513 [c042fe80] [c00314cc] irq_exit+0x88/0xb4
 514 [c042fe90] [c0006efc] do_IRQ+0xe0/0x234
 515 [c042fec0] [c0012bbc] ret_from_except+0x0/0x14
 516 --- Exception: 501 at cpu_idle+0xfc/0x10c
 517     LR = cpu_idle+0xfc/0x10c
 518 [c042ff80] [c000afb8] cpu_idle+0x68/0x10c (unreliable)
 519 [c042ffa0] [c0003ec0] rest_init+0x9c/0xbc
 520 [c042ffc0] [c03da91c] start_kernel+0x2c0/0x2d8
 521 [c042fff0] [00003438] 0x3438
 522 Unrecoverable FP Unavailable Exception 801 at c7985ca0
 523 Oops: Unrecoverable FP Unavailable Exception, sig: 6 [#1]
 524 PREEMPT Shark
 525 last sysfs file: /sys/devices/lpb.0/fc000000.flash/mtd/mtd2ro/dev
 526 Modules linked in:
 527 NIP: c7985ca0 LR: c025c200 CTR: c7985ca0
 528 REGS: c7ffbd20 TRAP: 0801   Not tainted  (2.6.36.1-00011-gdb0ddb5)
 529 MSR: 00009032 <EE,ME,IR,DR>  CR: 22002024  XER: 2000005f
 530 TASK = c0411520[0] 'swapper' THREAD: c042e000
 531 GPR00: c7985ca0 c7ffbdd0 c0411520 c7a49e20 c7985a60 00000010 c043b384 00004000
 532 GPR08: c043b788 00000000 00003fff c7ffbdd0 42002024
 533 NIP [c7985ca0] 0xc7985ca0
 534 LR [c025c200] dev_queue_xmit+0x104/0x428
 535 Call Trace:
 536 [c7ffbdd0] [c025c1a0] dev_queue_xmit+0xa4/0x428 (unreliable)
 537 [c7ffbe00] [c02d68d0] can_send+0x9c/0x1a0
 538 [c7ffbe20] [c02da27c] can_can_gw_rcv+0x108/0x164
 539 [c7ffbe50] [c02d5978] can_rcv_filter+0xf8/0x2e8
 540 [c7ffbe70] [c02d5c30] can_rcv+0xc8/0x140
 541 [c7ffbe90] [c025a694] __netif_receive_skb+0x2cc/0x338
 542 [c7ffbed0] [c025a8d8] netif_receive_skb+0x5c/0x98
 543 [c7ffbef0] [c0208938] mscan_rx_poll+0x1c0/0x454
 544 [c7ffbf50] [c025ac08] net_rx_action+0x104/0x230
 545 [c7ffbfa0] [c00317a8] __do_softirq+0x118/0x22c
 546 [c7ffbff0] [c0011eec] call_do_softirq+0x14/0x24
 547 [c042fe60] [c0006d78] do_softirq+0x84/0xa8
 548 [c042fe80] [c00314cc] irq_exit+0x88/0xb4
 549 [c042fe90] [c0006efc] do_IRQ+0xe0/0x234
 550 [c042fec0] [c0012bbc] ret_from_except+0x0/0x14
 551 --- Exception: 501 at cpu_idle+0xfc/0x10c
 552     LR = cpu_idle+0xfc/0x10c
 553 [c042ff80] [c000afb8] cpu_idle+0x68/0x10c (unreliable)
 554 [c042ffa0] [c0003ec0] rest_init+0x9c/0xbc
 555 [c042ffc0] [c03da91c] start_kernel+0x2c0/0x2d8
 556 [c042fff0] [00003438] 0x3438
 557 Instruction dump:
 558 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
 559 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
 560 Kernel panic - not syncing: Fatal exception in interrupt
 561 Call Trace:
 562 [c7ffbc10] [c0009c04] show_stack+0xb0/0x1d4 (unreliable)
 563 [c7ffbc60] [c0300434] dump_stack+0x2c/0x44
 564 [c7ffbc70] [c0300508] panic+0xbc/0x200
 565 [c7ffbcd0] [c000faf8] die+0x1a4/0x1cc
 566 [c7ffbcf0] [c000fc34] kernel_fp_unavailable_exception+0x4c/0x64
 567 [c7ffbd10] [c0012bbc] ret_from_except+0x0/0x14
 568 --- Exception: 801 at 0xc7985ca0
 569     LR = dev_queue_xmit+0x104/0x428
 570 [c7ffbdd0] [c025c1a0] dev_queue_xmit+0xa4/0x428 (unreliable)
 571 [c7ffbe00] [c02d68d0] can_send+0x9c/0x1a0
 572 [c7ffbe20] [c02da27c] can_can_gw_rcv+0x108/0x164
 573 [c7ffbe50] [c02d5978] can_rcv_filter+0xf8/0x2e8
 574 [c7ffbe70] [c02d5c30] can_rcv+0xc8/0x140
 575 [c7ffbe90] [c025a694] __netif_receive_skb+0x2cc/0x338
 576 [c7ffbed0] [c025a8d8] netif_receive_skb+0x5c/0x98
 577 [c7ffbef0] [c0208938] mscan_rx_poll+0x1c0/0x454
 578 [c7ffbf50] [c025ac08] net_rx_action+0x104/0x230
 579 [c7ffbfa0] [c00317a8] __do_softirq+0x118/0x22c
 580 [c7ffbff0] [c0011eec] call_do_softirq+0x14/0x24
 581 [c042fe60] [c0006d78] do_softirq+0x84/0xa8
 582 [c042fe80] [c00314cc] irq_exit+0x88/0xb4
 583 [c042fe90] [c0006efc] do_IRQ+0xe0/0x234
 584 [c042fec0] [c0012bbc] ret_from_except+0x0/0x14
 585 --- Exception: 501 at cpu_idle+0xfc/0x10c
 586     LR = cpu_idle+0xfc/0x10c
 587 [c042ff80] [c000afb8] cpu_idle+0x68/0x10c (unreliable)
 588 [c042ffa0] [c0003ec0] rest_init+0x9c/0xbc
 589 [c042ffc0] [c03da91c] start_kernel+0x2c0/0x2d8
 590 [c042fff0] [00003438] 0x3438
 591 ** After cansend can0
 592 BUG: spinlock bad magic on CPU#0, swapper/0
 593  lock: c7985abc, .magic: c0000000, .owner: <none>/-1, .owner_cpu: -1069424200
 594 Call Trace:
 595 [c7ffbd00] [c0009c04] show_stack+0xb0/0x1d4 (unreliable)
 596 [c7ffbd50] [c0300434] dump_stack+0x2c/0x44
 597 [c7ffbd60] [c01afa50] spin_bug+0x84/0xd0
 598 [c7ffbd80] [c01afbfc] do_raw_spin_lock+0x3c/0x15c
 599 [c7ffbdb0] [c02ffcec] _raw_spin_lock+0x34/0x4c
 600 [c7ffbdd0] [c025c1a0] dev_queue_xmit+0xa4/0x428
 601 [c7ffbe00] [c02d68d0] can_send+0x9c/0x1a0
 602 [c7ffbe20] [c02da27c] can_can_gw_rcv+0x108/0x164
 603 [c7ffbe50] [c02d5978] can_rcv_filter+0xf8/0x2e8
 604 [c7ffbe70] [c02d5c30] can_rcv+0xc8/0x140
 605 [c7ffbe90] [c025a694] __netif_receive_skb+0x2cc/0x338
 606 [c7ffbed0] [c025a8d8] netif_receive_skb+0x5c/0x98
 607 [c7ffbef0] [c0208938] mscan_rx_poll+0x1c0/0x454
 608 [c7ffbf50] [c025ac08] net_rx_action+0x104/0x230
 609 [c7ffbfa0] [c00317a8] __do_softirq+0x118/0x22c
 610 [c7ffbff0] [c0011eec] call_do_softirq+0x14/0x24
 611 [c042fe60] [c0006d78] do_softirq+0x84/0xa8
 612 [c042fe80] [c00314cc] irq_exit+0x88/0xb4
 613 [c042fe90] [c0006efc] do_IRQ+0xe0/0x234
 614 [c042fec0] [c0012bbc] ret_from_except+0x0/0x14
 615 --- Exception: 501 at cpu_idle+0xfc/0x10c
 616     LR = cpu_idle+0xfc/0x10c
 617 [c042ff80] [c000afb8] cpu_idle+0x68/0x10c (unreliable)
 618 [c042ffa0] [c0003ec0] rest_init+0x9c/0xbc
 619 [c042ffc0] [c03da91c] start_kernel+0x2c0/0x2d8
 620 [c042fff0] [00003438] 0x3438
 621 Unrecoverable FP Unavailable Exception 801 at c7985ca0
 622 Oops: Unrecoverable FP Unavailable Exception, sig: 6 [#1]
 623 PREEMPT Shark
 624 last sysfs file: /sys/devices/lpb.0/fc000000.flash/mtd/mtd2ro/dev
 625 Modules linked in:
 626 NIP: c7985ca0 LR: c025c200 CTR: c7985ca0
 627 REGS: c7ffbd20 TRAP: 0801   Not tainted  (2.6.36.1-00011-gdb0ddb5)
 628 MSR: 00009032 <EE,ME,IR,DR>  CR: 22002024  XER: 2000005f
 629 TASK = c0411520[0] 'swapper' THREAD: c042e000
 630 GPR00: c7985ca0 c7ffbdd0 c0411520 c7a49e20 c7985a60 00000010 c043b384 00004000
 631 GPR08: c043b788 00000000 00003fff c7ffbdd0 42002024
 632 NIP [c7985ca0] 0xc7985ca0
 633 LR [c025c200] dev_queue_xmit+0x104/0x428
 634 Call Trace:
 635 [c7ffbdd0] [c025c1a0] dev_queue_xmit+0xa4/0x428 (unreliable)
 636 [c7ffbe00] [c02d68d0] can_send+0x9c/0x1a0
 637 [c7ffbe20] [c02da27c] can_can_gw_rcv+0x108/0x164
 638 [c7ffbe50] [c02d5978] can_rcv_filter+0xf8/0x2e8
 639 [c7ffbe70] [c02d5c30] can_rcv+0xc8/0x140
 640 [c7ffbe90] [c025a694] __netif_receive_skb+0x2cc/0x338
 641 [c7ffbed0] [c025a8d8] netif_receive_skb+0x5c/0x98
 642 [c7ffbef0] [c0208938] mscan_rx_poll+0x1c0/0x454
 643 [c7ffbf50] [c025ac08] net_rx_action+0x104/0x230
 644 [c7ffbfa0] [c00317a8] __do_softirq+0x118/0x22c
 645 [c7ffbff0] [c0011eec] call_do_softirq+0x14/0x24
 646 [c042fe60] [c0006d78] do_softirq+0x84/0xa8
 647 [c042fe80] [c00314cc] irq_exit+0x88/0xb4
 648 [c042fe90] [c0006efc] do_IRQ+0xe0/0x234
 649 [c042fec0] [c0012bbc] ret_from_except+0x0/0x14
 650 --- Exception: 501 at cpu_idle+0xfc/0x10c
 651     LR = cpu_idle+0xfc/0x10c
 652 [c042ff80] [c000afb8] cpu_idle+0x68/0x10c (unreliable)
 653 [c042ffa0] [c0003ec0] rest_init+0x9c/0xbc
 654 [c042ffc0] [c03da91c] start_kernel+0x2c0/0x2d8
 655 [c042fff0] [00003438] 0x3438
 656 Instruction dump:
 657 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
 658 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
 659 Kernel panic - not syncing: Fatal exception in interrupt
 660 Call Trace:
 661 [c7ffbc10] [c0009c04] show_stack+0xb0/0x1d4 (unreliable)
 662 [c7ffbc60] [c0300434] dump_stack+0x2c/0x44
 663 [c7ffbc70] [c0300508] panic+0xbc/0x200
 664 [c7ffbcd0] [c000faf8] die+0x1a4/0x1cc
 665 [c7ffbcf0] [c000fc34] kernel_fp_unavailable_exception+0x4c/0x64
 666 [c7ffbd10] [c0012bbc] ret_from_except+0x0/0x14
 667 --- Exception: 801 at 0xc7985ca0
 668     LR = dev_queue_xmit+0x104/0x428
 669 [c7ffbdd0] [c025c1a0] dev_queue_xmit+0xa4/0x428 (unreliable)
 670 [c7ffbe00] [c02d68d0] can_send+0x9c/0x1a0
 671 [c7ffbe20] [c02da27c] can_can_gw_rcv+0x108/0x164
 672 [c7ffbe50] [c02d5978] can_rcv_filter+0xf8/0x2e8
 673 [c7ffbe70] [c02d5c30] can_rcv+0xc8/0x140
 674 [c7ffbe90] [c025a694] __netif_receive_skb+0x2cc/0x338
 675 [c7ffbed0] [c025a8d8] netif_receive_skb+0x5c/0x98
 676 [c7ffbef0] [c0208938] mscan_rx_poll+0x1c0/0x454
 677 [c7ffbf50] [c025ac08] net_rx_action+0x104/0x230
 678 [c7ffbfa0] [c00317a8] __do_softirq+0x118/0x22c
 679 [c7ffbff0] [c0011eec] call_do_softirq+0x14/0x24
 680 [c042fe60] [c0006d78] do_softirq+0x84/0xa8
 681 [c042fe80] [c00314cc] irq_exit+0x88/0xb4
 682 [c042fe90] [c0006efc] do_IRQ+0xe0/0x234
 683 [c042fec0] [c0012bbc] ret_from_except+0x0/0x14
 684 --- Exception: 501 at cpu_idle+0xfc/0x10c
 685     LR = cpu_idle+0xfc/0x10c
 686 [c042ff80] [c000afb8] cpu_idle+0x68/0x10c (unreliable)
 687 [c042ffa0] [c0003ec0] rest_init+0x9c/0xbc
 688 [c042ffc0] [c03da91c] start_kernel+0x2c0/0x2d8
 689 [c042fff0] [00003438] 0x3438
 690
 691 ** After cangw with modifications -m ...
 692 Unable to handle kernel paging request for data at address 0xdead4ead
 693 Faulting instruction address: 0xc025c178
 694 Oops: Kernel access of bad area, sig: 11 [#1]
 695 PREEMPT Shark
 696 last sysfs file: /sys/devices/lpb.0/fc000000.flash/mtd/mtd2ro/dev
 697 Modules linked in:
 698 NIP: c025c178 LR: c025c130 CTR: c02d90c4
 699 REGS: c7ffbd70 TRAP: 0300   Not tainted  (2.6.36.1-00005-gc63c5e8)
 700 MSR: 00009032 <EE,ME,IR,DR>  CR: 40008284  XER: 0000005f
 701 DAR: dead4ead, DSISR: 20000000
 702 TASK = c7a9ee10[369] 'cansend' THREAD: c7aca000
 703 GPR00: c7a31820 c7ffbe20 c7a9ee10 00000080 00000000 00000000 c7a4ef24 00000000
 704 GPR08: 00000000 00000002 00000001 c7ffbe20 40000282 10019f68 c042b0b0 00000001
 705 GPR16: c046da04 c042bcf0 c042bce0 c7ffa03c c0414924 c0432ac4 c0432ac0 c7abfc00
 706 GPR24: 00000000 c7a4eee0 c7a318a0 c7abf000 c7a37d24 c7a4eee0 dead4ead c7ffbe20
 707 NIP [c025c178] dev_queue_xmit+0x7c/0x428
 708 LR [c025c130] dev_queue_xmit+0x34/0x428
 709 Call Trace:
 710 [c7ffbe20] [c025c130] dev_queue_xmit+0x34/0x428 (unreliable)
 711 [c7ffbe50] [c02d68d0] can_send+0x9c/0x1a0
 712 [c7ffbe70] [c02da288] can_can_gw_rcv+0x114/0x170
 713 [c7ffbea0] [c02d5978] can_rcv_filter+0xf8/0x2e8
 714 [c7ffbec0] [c02d5c30] can_rcv+0xc8/0x140
 715 [c7ffbee0] [c025a694] __netif_receive_skb+0x2cc/0x338
 716 [c7ffbf20] [c025a7b8] process_backlog+0xb8/0x17c
 717 [c7ffbf50] [c025ac08] net_rx_action+0x104/0x230
 718 [c7ffbfa0] [c00317a8] __do_softirq+0x118/0x22c
 719 [c7ffbff0] [c0011eec] call_do_softirq+0x14/0x24
 720 [c7acbd60] [c0006d78] do_softirq+0x84/0xa8
 721 [c7acbd80] [c025b634] netif_rx_ni+0x6c/0x90
 722 [c7acbda0] [c02d691c] can_send+0xe8/0x1a0
 723 [c7acbdc0] [c02d7f80] raw_sendmsg+0xf4/0x168
 724 [c7acbdf0] [c0245cf8] sock_aio_write+0x104/0x134
 725 [c7acbe50] [c00c7848] do_sync_write+0xbc/0x110
 726 [c7acbef0] [c00c8638] vfs_write+0x170/0x190
 727 [c7acbf10] [c00c8778] sys_write+0x5c/0xa8
 728 [c7acbf40] [c0012524] ret_from_syscall+0x0/0x38
 729 --- Exception: c01 at 0xff23618
 730     LR = 0x1000094c
 731 Instruction dump:
 732 7fa4eb78 4e800421 801b01f0 7c7e1b78 5469043e 7f830040 54633032 409c01b4
 733 b13d0074 801b01e8 7f401a14 83da0004 <801e0000> 2f800000 419e0254 801e0078
 734 Kernel panic - not syncing: Fatal exception in interrupt
 735 Call Trace:
 736 [c7ffbc60] [c0009c04] show_stack+0xb0/0x1d4 (unreliable)
 737 [c7ffbcb0] [c030043c] dump_stack+0x2c/0x44
 738 [c7ffbcc0] [c0300510] panic+0xbc/0x200
 739 [c7ffbd20] [c000faf8] die+0x1a4/0x1cc
 740 [c7ffbd40] [c0014374] bad_page_fault+0x90/0xe0
 741 [c7ffbd60] [c00129c4] handle_page_fault+0x7c/0x80
 742 --- Exception: 300 at dev_queue_xmit+0x7c/0x428
 743     LR = dev_queue_xmit+0x34/0x428
 744 [c7ffbe50] [c02d68d0] can_send+0x9c/0x1a0
 745 [c7ffbe70] [c02da288] can_can_gw_rcv+0x114/0x170
 746 [c7ffbea0] [c02d5978] can_rcv_filter+0xf8/0x2e8
 747 [c7ffbec0] [c02d5c30] can_rcv+0xc8/0x140
 748 [c7ffbee0] [c025a694] __netif_receive_skb+0x2cc/0x338
 749 [c7ffbf20] [c025a7b8] process_backlog+0xb8/0x17c
 750 [c7ffbf50] [c025ac08] net_rx_action+0x104/0x230
 751 [c7ffbfa0] [c00317a8] __do_softirq+0x118/0x22c
 752 [c7ffbff0] [c0011eec] call_do_softirq+0x14/0x24
 753 [c7acbd60] [c0006d78] do_softirq+0x84/0xa8
 754 [c7acbd80] [c025b634] netif_rx_ni+0x6c/0x90
 755 [c7acbda0] [c02d691c] can_send+0xe8/0x1a0
 756 [c7acbdc0] [c02d7f80] raw_sendmsg+0xf4/0x168
 757 [c7acbdf0] [c0245cf8] sock_aio_write+0x104/0x134
 758 [c7acbe50] [c00c7848] do_sync_write+0xbc/0x110
 759 [c7acbef0] [c00c8638] vfs_write+0x170/0x190
 760 [c7acbf10] [c00c8778] sys_write+0x5c/0xa8
 761 [c7acbf40] [c0012524] ret_from_syscall+0x0/0x38
 762 --- Exception: c01 at 0xff23618
 763     LR = 0x1000094c
 764
 765 * write returns ENOBUFS
 766 The reason is queuing discipline - the queue is full and
 767 pfifo_fast_enqueue returns failure. This failure is propagated down to
 768 qdisc_enqueue_root(), __dev_xmit_skb(), dev_queue_xmit() and
 769 can_send()
 770
 771 ** See the follwing trace
 772
 773 # tracer: function_graph
 774 #
 775 # CPU  DURATION                  FUNCTION CALLS
 776 # |     |   |                     |   |   |   |
 777  1)               |  can_send() {
 778  1)               |    dev_queue_xmit() {
 779  1)               |      rt_spin_lock() {
 780  1)   0.894 us    |        __might_sleep();
 781  1)   2.750 us    |      }
 782  1)               |      pfifo_fast_enqueue() {
 783  1)               |        kfree_skb() {
 784  1)               |          __kfree_skb() {
 785  1)               |            skb_release_head_state() {
 786  1)               |              sock_wfree() {
 787  1)               |                sock_def_write_space() {
 788  1)               |                  rt_read_lock() {
 789  1)               |                    __rt_spin_lock() {
 790  1)   0.677 us    |                      __might_sleep();
 791  1)   2.386 us    |                    }
 792  1)   4.150 us    |                  }
 793  1)               |                  rt_read_unlock() {
 794  1)   0.918 us    |                    __rt_spin_unlock();
 795  1)   2.644 us    |                  }
 796  1)   9.375 us    |                }
 797  1) + 10.999 us   |              }
 798  1) + 12.708 us   |            }
 799  1)               |            skb_release_data() {
 800  1)               |              kfree() {
 801  1)               |                _slab_irq_disable() {
 802  1)               |                  rt_spin_lock() {
 803  1)   0.849 us    |                    __might_sleep();
 804  1)   2.588 us    |                  }
 805  1)   4.242 us    |                }
 806  1)   0.864 us    |                __cache_free();
 807  1)   0.888 us    |                rt_spin_unlock();
 808  1)   9.456 us    |              }
 809  1) + 11.185 us   |            }
 810  1)               |            kmem_cache_free() {
 811  1)               |              _slab_irq_disable() {
 812  1)               |                rt_spin_lock() {
 813  1)   0.812 us    |                  __might_sleep();
 814  1)   2.542 us    |                }
 815  1)   4.240 us    |              }
 816  1)   0.813 us    |              __cache_free();
 817  1)   0.894 us    |              rt_spin_unlock();
 818  1)   9.329 us    |            }
 819  1) + 36.444 us   |          }
 820  1) + 38.136 us   |        }
 821  1) + 39.974 us   |      }
 822  1)               |      /* qdisc_enqueue_root = 1 */
 823  1)               |      __qdisc_run() {
 824  1)               |        sch_direct_xmit() {
 825  1)   0.855 us    |          rt_spin_unlock();
 826  1)               |          rt_spin_lock() {
 827  1)   0.827 us    |            __might_sleep();
 828  1)   2.521 us    |          }
 829  1)               |          dev_hard_start_xmit() {
 830  1)               |            sja1000_start_xmit() {
 831  1)   1.646 us    |              kvaser_pci_write_reg();
 832  1)   1.460 us    |              kvaser_pci_write_reg();
 833  1)   1.691 us    |              kvaser_pci_write_reg();
 834  1)   1.450 us    |              kvaser_pci_write_reg();
 835  1)   1.416 us    |              kvaser_pci_write_reg();
 836  1)               |              can_put_echo_skb() {
 837  1)               |                sock_wfree() {
 838  1)               |                  sock_def_write_space() {
 839  1)               |                    rt_read_lock() {
 840  1)               |                      __rt_spin_lock() {
 841  1)   0.939 us    |                        __might_sleep();
 842  1)   2.699 us    |                      }
 843  1)   4.337 us    |                    }
 844  1)               |                    rt_read_unlock() {
 845  1)   0.844 us    |                      __rt_spin_unlock();
 846  1)   2.507 us    |                    }
 847  1)   9.242 us    |                  }
 848  1) + 11.047 us   |                }
 849  1) + 12.791 us   |              }
 850  1)               |              sja1000_write_cmdreg() {
 851  1)               |                rt_spin_lock() {
 852  1)   0.802 us    |                  __might_sleep();
 853  1)   2.532 us    |                }
 854  1)   1.481 us    |                kvaser_pci_write_reg();
 855  1)   2.155 us    |                kvaser_pci_read_reg();
 856  1)   0.843 us    |                rt_spin_unlock();
 857  1) + 11.100 us   |              }
 858  1) + 38.263 us   |            }
 859  1)               |            /* ops->ndo_start_xmit(skb, dev) = 0 */
 860  1) + 41.508 us   |          }
 861  1)               |          /* dev_hard_start_xmit(skb, dev) = 0 */
 862  1)   0.884 us    |          rt_spin_unlock();
 863  1)               |          rt_spin_lock() {
 864  1)   0.817 us    |            __might_sleep();
 865  1)   2.583 us    |          }
 866  1)               |          /* qdisc_len = 9 */
 867  1)               |          /* sch_direct_xmit returns 0 */
 868  1) + 57.502 us   |        }
 869  1) + 59.288 us   |      }
 870  1)   0.877 us    |      rt_spin_unlock();
 871  1)               |      /* __dev_xmit_skb = 1 */
 872  1) ! 111.265 us  |    }
 873  1)               |  /* dev_queue_xmit = 1 */
 874  1)               |  /* net_xmit_errno = -105 */
 875  1)   0.956 us    |    kfree_skb();
 876  1) ! 117.340 us  |  }
 877  1)               |  /* write returned -1 */
 878
 879 ** The trace was generated by kernel v2.6.33.7-rt29-4-g92487e4 with the following patch applied:
 880
 881 diff --git a/net/can/af_can.c b/net/can/af_can.c
 882 index 4d8479d7..c91968d 100644
 883 --- a/net/can/af_can.c
 884 +++ b/net/can/af_can.c
 885 @@ -344,8 +344,11 @@ int can_send(struct sk_buff *skb, int loop)
 886
 887         /* send to netdevice */
 888         err = dev_queue_xmit(skb);
 889 -       if (err > 0)
 890 +       trace_printk("dev_queue_xmit = %d\n", err);
 891 +       if (err > 0) {
 892                 err = net_xmit_errno(err);
 893 +               trace_printk("net_xmit_errno = %d\n", err);
 894 +       }
 895
 896         if (err) {
 897  #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,17)
 898 diff --git a/net/core/dev.c b/net/core/dev.c
 899 index 7a5412e..10ca9b4 100644
 900 --- a/net/core/dev.c
 901 +++ b/net/core/dev.c
 902 @@ -1828,6 +1828,8 @@ int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
 903                         skb_dst_drop(skb);
 904
 905                 rc = ops->ndo_start_xmit(skb, dev);
 906 +               trace_printk("ops->ndo_start_xmit(skb, dev) = %d\n", rc);
 907 +
 908                 if (rc == NETDEV_TX_OK)
 909                         txq_trans_update(txq);
 910                 /*
 911 @@ -1854,6 +1856,7 @@ gso:
 912                 skb->next = nskb->next;
 913                 nskb->next = NULL;
 914                 rc = ops->ndo_start_xmit(nskb, dev);
 915 +               trace_printk("gso: ops->ndo_start_xmit(skb, dev) = %d\n", rc);
 916                 if (unlikely(rc != NETDEV_TX_OK)) {
 917                         if (rc & ~NETDEV_TX_MASK)
 918                                 goto out_kfree_gso_skb;
 919 @@ -1949,6 +1952,8 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
 920         spin_lock(root_lock);
 921         if (unlikely(test_bit(__QDISC_STATE_DEACTIVATED, &q->state))) {
 922                 kfree_skb(skb);
 923 +               trace_printk("QDISC_STATE_DEACTIVATED\n");
 924 +
 925                 rc = NET_XMIT_DROP;
 926         } else if ((q->flags & TCQ_F_CAN_BYPASS) && !qdisc_qlen(q) &&
 927                    !test_and_set_bit(__QDISC_STATE_RUNNING, &q->state)) {
 928 @@ -1966,6 +1971,7 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
 929                 rc = NET_XMIT_SUCCESS;
 930         } else {
 931                 rc = qdisc_enqueue_root(skb, q);
 932 +               trace_printk("qdisc_enqueue_root = %d\n", rc);
 933                 qdisc_run(q);
 934         }
 935         spin_unlock(root_lock);
 936 @@ -2047,6 +2053,7 @@ gso:
 937  #endif
 938         if (q->enqueue) {
 939                 rc = __dev_xmit_skb(skb, q, dev, txq);
 940 +               trace_printk("__dev_xmit_skb = %d\n", rc);
 941                 goto out;
 942         }
 943
 944 @@ -2072,6 +2079,8 @@ gso:
 945
 946                         if (!netif_tx_queue_stopped(txq)) {
 947                                 rc = dev_hard_start_xmit(skb, dev, txq);
 948 +                               trace_printk("dev_hard_start_xmit = %d\n", rc);
 949 +
 950                                 if (dev_xmit_complete(rc)) {
 951                                         HARD_TX_UNLOCK(dev, txq);
 952                                         goto out;
 953 diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
 954 index bf7f50e..aea0833 100644
 955 --- a/net/sched/sch_generic.c
 956 +++ b/net/sched/sch_generic.c
 957 @@ -125,6 +125,7 @@ int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
 958         HARD_TX_LOCK(dev, txq);
 959         if (!netif_tx_queue_stopped(txq) && !netif_tx_queue_frozen(txq))
 960                 ret = dev_hard_start_xmit(skb, dev, txq);
 961 +       trace_printk("dev_hard_start_xmit(skb, dev) = %d\n", ret);
 962
 963         HARD_TX_UNLOCK(dev, txq);
 964
 965 @@ -133,9 +134,11 @@ int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
 966         if (dev_xmit_complete(ret)) {
 967                 /* Driver sent out skb successfully or skb was consumed */
 968                 ret = qdisc_qlen(q);
 969 +               trace_printk("qdisc_len = %d\n", ret);
 970         } else if (ret == NETDEV_TX_LOCKED) {
 971                 /* Driver try lock failed */
 972                 ret = handle_dev_cpu_collision(skb, txq, q);
 973 +               trace_printk("handle_dev_cpu_collision = %d\n", ret);
 974         } else {
 975                 /* Driver returned NETDEV_TX_BUSY - requeue skb */
 976                 if (unlikely (ret != NETDEV_TX_BUSY && net_ratelimit()))
 977 @@ -143,12 +146,13 @@ int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
 978                                dev->name, ret, q->q.qlen);
 979
 980                 ret = dev_requeue_skb(skb, q);
 981 +               trace_printk("dev_requeue_skb = %d\n", ret);
 982         }
 983
 984         if (ret && (netif_tx_queue_stopped(txq) ||
 985                     netif_tx_queue_frozen(txq)))
 986                 ret = 0;
 987 -
 988 +       trace_printk("%s returns %d\n", __FUNCTION__, ret);
 989         return ret;
 990  }
 991