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 * Kernel oops
  15 ** Linux-2.6.33.7-00005-ge2f49b5
  16 Unable to handle kernel paging request for instruction fetch
  17 Faulting instruction address: 0x8d56acc4
  18 Oops: Kernel access of bad area, sig: 11 [#1]
  19 PREEMPT Shark
  20 Modules linked in:
  21 NIP: 8d56acc4 LR: c0260208 CTR: 8d56acc7
  22 REGS: c03f3bc0 TRAP: 0400   Not tainted  (2.6.33.7-00005-ge2f49b5)
  23 MSR: 20009032 <EE,ME,IR,DR>  CR: 24008028  XER: 0000005f
  24 TASK = c03d5478[0] 'swapper' THREAD: c03f2000
  25 GPR00: 8d56acc7 c03f3c70 c03d5478 c7990160 c78d54ad 00000048 c79901a4 00000002
  26 GPR08: 000000e0 00000000 00000001 00000002 44000022 7f33ff4e 80000000 00000042
  27 GPR16: 00000008 20000000 c909e900 00000001 c03f3d78 c79326e0 00000008 c799dc1c
  28 GPR24: c7976800 c78d54f9 c7949828 c7a06620 c03f2000 c7990160 c78d54ad c03f3c70
  29 NIP [8d56acc4] 0x8d56acc4
  30 LR [c0260208] dev_queue_xmit+0x2f0/0x588
  31 Call Trace:
  32 [c03f3c70] [c025ff74] dev_queue_xmit+0x5c/0x588 (unreliable)
  33 [c03f3ca0] [c02d62d8] can_send+0x9c/0x1a0
  34 [c03f3cc0] [c02d97a8] can_can_gw_rcv+0x108/0x164
  35 [c03f3cf0] [c02d52ac] can_rcv_filter+0x240/0x2e8
  36 [c03f3d10] [c02d541c] can_rcv+0xc8/0x140
  37 [c03f3d30] [c025e968] netif_receive_skb+0x2ac/0x350
  38 [c03f3d70] [c020a230] mscan_rx_poll+0x1c0/0x464
  39 [c03f3dd0] [c025f428] net_rx_action+0x104/0x22c
  40 [c03f3e20] [c00345e0] __do_softirq+0x10c/0x21c
  41 [c03f3e70] [c00075d0] do_softirq+0x58/0x74
  42 [c03f3e80] [c0034300] irq_exit+0x8c/0xbc
  43 [c03f3e90] [c00076c8] do_IRQ+0xdc/0x188
  44 [c03f3ec0] [c0014db0] ret_from_except+0x0/0x14
  45 --- Exception: 501 at cpu_idle+0x104/0x114
  46     LR = cpu_idle+0x104/0x114
  47 [c03f3f80] [c000aefc] cpu_idle+0x68/0x114 (unreliable)
  48 [c03f3fa0] [c0003f40] rest_init+0xa4/0xc4
  49 [c03f3fc0] [c039f918] start_kernel+0x2e4/0x2fc
  50 [c03f3ff0] [00003438] 0x3438
  51 Instruction dump:
  52 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
  53 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
  54 Kernel panic - not syncing: Fatal exception in interrupt
  55 Call Trace:
  56 [c03f3ab0] [c0009cdc] show_stack+0x70/0x1d4 (unreliable)
  57 [c03f3b00] [c02ff5ec] dump_stack+0x2c/0x44
  58 [c03f3b10] [c02ff6b0] panic+0xac/0x19c
  59 [c03f3b60] [c0011df8] die+0x188/0x1a4
  60 [c03f3b90] [c00165c8] bad_page_fault+0x90/0xe0
  61 [c03f3bb0] [c0014bb8] handle_page_fault+0x7c/0x80
  62 --- Exception: 400 at 0x8d56acc4
  63     LR = dev_queue_xmit+0x2f0/0x588
  64 [c03f3c70] [c025ff74] dev_queue_xmit+0x5c/0x588 (unreliable)
  65 [c03f3ca0] [c02d62d8] can_send+0x9c/0x1a0
  66 [c03f3cc0] [c02d97a8] can_can_gw_rcv+0x108/0x164
  67 [c03f3cf0] [c02d52ac] can_rcv_filter+0x240/0x2e8
  68 [c03f3d10] [c02d541c] can_rcv+0xc8/0x140
  69 [c03f3d30] [c025e968] netif_receive_skb+0x2ac/0x350
  70 [c03f3d70] [c020a230] mscan_rx_poll+0x1c0/0x464
  71 [c03f3dd0] [c025f428] net_rx_action+0x104/0x22c
  72 [c03f3e20] [c00345e0] __do_softirq+0x10c/0x21c
  73 [c03f3e70] [c00075d0] do_softirq+0x58/0x74
  74 [c03f3e80] [c0034300] irq_exit+0x8c/0xbc
  75 [c03f3e90] [c00076c8] do_IRQ+0xdc/0x188
  76 [c03f3ec0] [c0014db0] ret_from_except+0x0/0x14
  77 --- Exception: 501 at cpu_idle+0x104/0x114
  78     LR = cpu_idle+0x104/0x114
  79 [c03f3f80] [c000aefc] cpu_idle+0x68/0x114 (unreliable)
  80 [c03f3fa0] [c0003f40] rest_init+0xa4/0xc4
  81 [c03f3fc0] [c039f918] start_kernel+0x2e4/0x2fc
  82 [c03f3ff0] [00003438] 0x3438
  83 Rebooting in 180 seconds..
  84
  85 ** Current kernel
  86 Unable to handle kernel paging request for instruction fetch
  87 Faulting instruction address: 0x8cd6acc4
  88 Oops: Kernel access of bad area, sig: 11 [#1]
  89 PREEMPT Shark
  90 Modules linked in:
  91 NIP: 8cd6acc4 LR: c025fdac CTR: 8cd6acc7
  92 REGS: c03f3bd0 TRAP: 0400   Not tainted  (2.6.33.7-00005-ge2f49b5)
  93 MSR: 20009032 <EE,ME,IR,DR>  CR: 22008028  XER: 0000005f
  94 TASK = c03d6478[0] 'swapper' THREAD: c03f2000
  95 GPR00: 8cd6acc7 c03f3c80 c03d6478 c79fec00 c78cd4ad 00000048 c79fec44 00000002
  96 GPR08: 000000e0 00000000 00000001 c03f3c80 42000022 7f33ff4e 80000000 00000042
  97 GPR16: 00000008 20000000 c909e900 00000001 c03f3d88 c79386e0 00000008 c79fe51c
  98 GPR24: 0000000c c78cd4f9 c7975800 c7949828 c7a33d24 c79fec00 c78cd4ad c03f3c80
  99 NIP [8cd6acc4] 0x8cd6acc4
 100 LR [c025fdac] dev_queue_xmit+0xec/0x588
 101 Call Trace:
 102 [c03f3c80] [c025fd68] dev_queue_xmit+0xa8/0x588 (unreliable)
 103 [c03f3cb0] [c02d5128] can_send+0x9c/0x1a0
 104 [c03f3cd0] [c02d85ec] can_can_gw_rcv+0x108/0x164
 105 [c03f3d00] [c02d3fdc] can_rcv_filter+0xf8/0x2e8
 106 [c03f3d20] [c02d4294] can_rcv+0xc8/0x140
 107 [c03f3d40] [c025e6f8] netif_receive_skb+0x2a8/0x34c
 108 [c03f3d80] [c020a774] mscan_rx_poll+0x1c0/0x464
 109 [c03f3de0] [c025f1b8] net_rx_action+0x104/0x238
 110 [c03f3e30] [c00368c8] __do_softirq+0x128/0x244
 111 [c03f3e80] [c00075e0] do_softirq+0x64/0x80
 112 [c03f3e90] [c00365d0] irq_exit+0x98/0xc4
 113 [c03f3ea0] [c00076d8] do_IRQ+0xdc/0x188
 114 [c03f3ed0] [c0014d40] ret_from_except+0x0/0x14
 115 [c03f3f90] [c000aed8] cpu_idle+0x68/0x10c (unreliable)
 116 --- Exception: 501 at cpu_idle+0xfc/0x10c
 117     LR = cpu_idle+0xfc/0x10c
 118 [c03f3fb0] [c0003f34] rest_init+0x98/0xc4
 119 [c03f3fc0] [c039f914] start_kernel+0x2e0/0x2f8
 120 [c03f3ff0] [00003438] 0x3438
 121 Instruction dump:
 122 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
 123 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
 124 Kernel panic - not syncing: Fatal exception in interrupt
 125 Call Trace:
 126 [c03f3ac0] [c0009cc0] show_stack+0x70/0x1d4 (unreliable)
 127 [c03f3b10] [c02fde74] dump_stack+0x2c/0x44
 128 [c03f3b20] [c02fdf30] panic+0xa4/0x19c
 129 [c03f3b70] [c0011d90] die+0x184/0x1a0
 130 --- Exception: c03f3d88 at 0x42000022
 131     LR = 0x8
 132 [c03f3ba0] [c0016558] bad_page_fault+0x90/0xe0 (unreliable)
 133 [c03f3bc0] [c0014b48] handle_page_fault+0x7c/0x80
 134 --- Exception: 400 at 0x8cd6acc4
 135     LR = dev_queue_xmit+0xec/0x588
 136 [c03f3c80] [c025fd68] dev_queue_xmit+0xa8/0x588 (unreliable)
 137 [c03f3cb0] [c02d5128] can_send+0x9c/0x1a0
 138 [c03f3cd0] [c02d85ec] can_can_gw_rcv+0x108/0x164
 139 [c03f3d00] [c02d3fdc] can_rcv_filter+0xf8/0x2e8
 140 [c03f3d20] [c02d4294] can_rcv+0xc8/0x140
 141 [c03f3d40] [c025e6f8] netif_receive_skb+0x2a8/0x34c
 142 [c03f3d80] [c020a774] mscan_rx_poll+0x1c0/0x464
 143 [c03f3de0] [c025f1b8] net_rx_action+0x104/0x238
 144 [c03f3e30] [c00368c8] __do_softirq+0x128/0x244
 145 [c03f3e80] [c00075e0] do_softirq+0x64/0x80
 146 [c03f3e90] [c00365d0] irq_exit+0x98/0xc4
 147 [c03f3ea0] [c00076d8] do_IRQ+0xdc/0x188
 148 [c03f3ed0] [c0014d40] ret_from_except+0x0/0x14
 149 --- Exception: 501 at cpu_idle+0xfc/0x10c
 150     LR = cpu_idle+0xfc/0x10c
 151 [c03f3f90] [c000aed8] cpu_idle+0x68/0x10c (unreliable)
 152 [c03f3fb0] [c0003f34] rest_init+0x98/0xc4
 153 [c03f3fc0] [c039f914] start_kernel+0x2e0/0x2f8
 154 [c03f3ff0] [00003438] 0x3438
 155
 156
 157 *** Disassemble
 158         if (q->enqueue) {
 159 c025fd54:       80 1e 00 00     lwz     r0,0(r30)
 160 c025fd58:       2f 80 00 00     cmpwi   cr7,r0,0
 161 c025fd5c:       41 9e 01 94     beq-    cr7,c025fef0 <dev_queue_xmit+0x230>
 162         raw_spin_lock_init(&(_lock)->rlock);            \
 163 } while (0)
 164
 165 static inline void spin_lock(spinlock_t *lock)
 166 {
 167         raw_spin_lock(&lock->rlock);
 168 c025fd60:       38 60 00 01     li      r3,1
 169 c025fd64:       4b dc 47 cd     bl      c0024530 <add_preempt_count>
 170 c025fd68:       80 1e 00 4c     lwz     r0,76(r30) !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 171 {
 172         spinlock_t *root_lock = qdisc_lock(q);
 173         int rc;
 174
 175         spin_lock(root_lock);
 176         if (unlikely(test_bit(__QDISC_STATE_DEACTIVATED, &q->state))) {
 177 c025fd6c:       3b 3e 00 4c     addi    r25,r30,76
 178 c025fd70:       70 09 00 04     andi.   r9,r0,4
 179 c025fd74:       40 82 01 f0     bne-    c025ff64 <dev_queue_xmit+0x2a4>
 180
 181 *** Corresponding C code
 182 static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
 183                                  struct net_device *dev,
 184                                  struct netdev_queue *txq)
 185 {
 186         spinlock_t *root_lock = qdisc_lock(q);
 187         int rc;
 188
 189         spin_lock(root_lock);
 190
 191 ** 2.6.36.1-00006-g2e11adb
 192 Unable to handle kernel paging request for data at address 0xfffffffe
 193 Faulting instruction address: 0xc0262358
 194 Oops: Kernel access of bad area, sig: 11 [#1]
 195 PREEMPT Shark
 196 last sysfs file: /sys/devices/lpb.0/fc000000.flash/mtd/mtd2ro/dev
 197 Modules linked in:
 198 NIP: c0262358 LR: c026218c CTR: 00000000
 199 REGS: c7ffbd20 TRAP: 0300   Not tainted  (2.6.36.1-00006-g2e11adb)
 200 MSR: 00009032 <EE,ME,IR,DR>  CR: 42008024  XER: 0000005f
 201 DAR: fffffffe, DSISR: 20000000
 202 TASK = c03e44d0[0] 'swapper' THREAD: c0400000
 203 GPR00: c7939560 c7ffbdd0 c03e44d0 00000100 00000000 00000060 c798bb64 00000000
 204 GPR08: 000000e8 00000002 00000001 00000002 42000022 7f33ff4e 80000000 00000042
 205 GPR16: 00000008 20000000 c909e900 00000001 c7ffbef8 c0404a84 c0404a80 c78b4000
 206 GPR24: 00000000 c798bb20 c79395c0 c7a77e20 c796f800 c798bb20 fffffffe c7ffbdd0
 207 NIP [c0262358] dev_queue_xmit+0x200/0x4f0
 208 LR [c026218c] dev_queue_xmit+0x34/0x4f0
 209 Call Trace:
 210 [c7ffbdd0] [c026218c] dev_queue_xmit+0x34/0x4f0 (unreliable)
 211 [c7ffbe00] [c02dd1f4] can_send+0x9c/0x1a0
 212 [c7ffbe20] [c02e07a8] can_can_gw_rcv+0x108/0x164
 213 [c7ffbe50] [c02dc224] can_rcv_filter+0xf8/0x2e8
 214 [c7ffbe70] [c02dc4dc] can_rcv+0xc8/0x140
 215 [c7ffbe90] [c02606f0] __netif_receive_skb+0x2cc/0x338
 216 [c7ffbed0] [c0260934] netif_receive_skb+0x5c/0x98
 217 [c7ffbef0] [c020d72c] mscan_rx_poll+0x1c0/0x454
 218 [c7ffbf50] [c0260c64] net_rx_action+0x104/0x230
 219 [c7ffbfa0] [c0031350] __do_softirq+0x118/0x22c
 220 [c7ffbff0] [c0011704] call_do_softirq+0x14/0x24
 221 [c0401e60] [c0006bdc] do_softirq+0x84/0xa8
 222 [c0401e80] [c0031074] irq_exit+0x88/0xb4
 223 [c0401e90] [c0006d60] do_IRQ+0xe0/0x234
 224 [c0401ec0] [c00123d4] ret_from_except+0x0/0x14
 225 --- Exception: 501 at cpu_idle+0xfc/0x10c
 226     LR = cpu_idle+0xfc/0x10c
 227 [c0401f80] [c000a7a8] cpu_idle+0x68/0x10c (unreliable)
 228 [c0401fa0] [c0003ec0] rest_init+0x9c/0xbc
 229 [c0401fc0] [c03ad91c] start_kernel+0x2c0/0x2d8
 230 [c0401ff0] [00003438] 0x3438
 231 Instruction dump:
 232 41920198 817e000c 2f8b0000 419c018c 55693032 55602036 7ca04850 5569043e
 233 b13d0074 801c01c8 7f402a14 83da0004 <801e0000> 2f800000 409efe88 801c00d8
 234 Kernel panic - not syncing: Fatal exception in interrupt
 235 Call Trace:
 236 [c7ffbc00] [c00095dc] show_stack+0xb0/0x1d4 (unreliable)
 237 [c7ffbc50] [c030664c] dump_stack+0x2c/0x44
 238 [c7ffbc60] [c0306720] panic+0xbc/0x1fc
 239 [c7ffbcc0] [c000f34c] die+0x1b8/0x1e8
 240 --- Exception: c7ffbef8 at 0x42000022
 241     LR = 0x8
 242 [c7ffbcf0] [c0013b8c] bad_page_fault+0x90/0xe0 (unreliable)
 243 [c7ffbd10] [c00121dc] handle_page_fault+0x7c/0x80
 244 --- Exception: 300 at dev_queue_xmit+0x200/0x4f0
 245     LR = dev_queue_xmit+0x34/0x4f0
 246 [c7ffbe00] [c02dd1f4] can_send+0x9c/0x1a0
 247 [c7ffbe20] [c02e07a8] can_can_gw_rcv+0x108/0x164
 248 [c7ffbe50] [c02dc224] can_rcv_filter+0xf8/0x2e8
 249 [c7ffbe70] [c02dc4dc] can_rcv+0xc8/0x140
 250 [c7ffbe90] [c02606f0] __netif_receive_skb+0x2cc/0x338
 251 [c7ffbed0] [c0260934] netif_receive_skb+0x5c/0x98
 252 [c7ffbef0] [c020d72c] mscan_rx_poll+0x1c0/0x454
 253 [c7ffbf50] [c0260c64] net_rx_action+0x104/0x230
 254 [c7ffbfa0] [c0031350] __do_softirq+0x118/0x22c
 255 [c7ffbff0] [c0011704] call_do_softirq+0x14/0x24
 256 [c0401e60] [c0006bdc] do_softirq+0x84/0xa8
 257 [c0401e80] [c0031074] irq_exit+0x88/0xb4
 258 [c0401e90] [c0006d60] do_IRQ+0xe0/0x234
 259 [c0401ec0] [c00123d4] ret_from_except+0x0/0x14
 260 --- Exception: 501 at cpu_idle+0xfc/0x10c
 261     LR = cpu_idle+0xfc/0x10c
 262 [c0401f80] [c000a7a8] cpu_idle+0x68/0x10c (unreliable)
 263 [c0401fa0] [c0003ec0] rest_init+0x9c/0xbc
 264 [c0401fc0] [c03ad91c] start_kernel+0x2c0/0x2d8
 265 [c0401ff0] [00003438] 0x3438
 266
 267 ** With "Spinlock and rw-lock debugging: basic checks"
 268 BUG: spinlock bad magic on CPU#0, swapper/0
 269  lock: c7985abc, .magic: c0000000, .owner: <none>/-1, .owner_cpu: -1069448776
 270
 271
 272 ** With "Spinlock debugging: sleep-inside-spinlock checking"
 273 BUG: sleeping function called from invalid context at /home/wsh/projects/can-benchmark/kernel/2.6.36/mm/slab.c:3101
 274 in_atomic(): 1, irqs_disabled(): 0, pid: 379, name: cangw
 275 Call Trace:
 276 [c7abdb50] [c0009c04] show_stack+0xb0/0x1d4 (unreliable)
 277 [c7abdba0] [c02ffe54] dump_stack+0x2c/0x44
 278 [c7abdbb0] [c002157c] __might_sleep+0xfc/0x124
 279 [c7abdbc0] [c00c45bc] kmem_cache_alloc+0x15c/0x180
 280 [c7abdbf0] [c02d60d8] can_rx_register+0x78/0x210
 281 [c7abdc30] [c02d9ebc] cgw_create_job+0x1cc/0x220
 282 [c7abdc50] [c026c208] rtnetlink_rcv_msg+0x21c/0x28c
 283 [c7abdc70] [c02762a4] netlink_rcv_skb+0xb8/0x100
 284 [c7abdc90] [c026bfd0] rtnetlink_rcv+0x40/0x5c
 285 [c7abdcb0] [c0275e9c] netlink_unicast+0x320/0x368
 286 [c7abdd00] [c0276a0c] netlink_sendmsg+0x2e0/0x33c
 287 [c7abdd50] [c0244cc0] sock_sendmsg+0x9c/0xd4
 288 [c7abde20] [c0247194] sys_sendto+0xcc/0x108
 289 [c7abdf00] [c0248980] sys_socketcall+0x17c/0x218
 290 [c7abdf40] [c0012524] ret_from_syscall+0x0/0x38
 291 --- Exception: c01 at 0xff3413c
 292     LR = 0x10001f9c
 293 BUG: spinlock bad magic on CPU#0, swapper/0
 294  lock: c798aabc, .magic: c0000000, .owner: <none>/-1, .owner_cpu: -1069424200
 295 Call Trace:
 296 [c7ffbd00] [c0009c04] show_stack+0xb0/0x1d4 (unreliable)
 297 [c7ffbd50] [c02ffe54] dump_stack+0x2c/0x44
 298 [c7ffbd60] [c01afa50] spin_bug+0x84/0xd0
 299 [c7ffbd80] [c01afbfc] do_raw_spin_lock+0x3c/0x15c
 300 [c7ffbdb0] [c02ff70c] _raw_spin_lock+0x34/0x4c
 301 [c7ffbdd0] [c025bbdc] dev_queue_xmit+0xa4/0x428
 302 [c7ffbe00] [c02d630c] can_send+0x9c/0x1a0
 303 [c7ffbe20] [c02d991c] can_can_gw_rcv+0x108/0x164
 304 [c7ffbe50] [c02d53b4] can_rcv_filter+0xf8/0x2e8
 305 [c7ffbe70] [c02d566c] can_rcv+0xc8/0x140
 306 [c7ffbe90] [c025a0d0] __netif_receive_skb+0x2cc/0x338
 307 [c7ffbed0] [c025a314] netif_receive_skb+0x5c/0x98
 308 [c7ffbef0] [c0208374] mscan_rx_poll+0x1c0/0x454
 309 [c7ffbf50] [c025a644] net_rx_action+0x104/0x230
 310 [c7ffbfa0] [c00317a8] __do_softirq+0x118/0x22c
 311 [c7ffbff0] [c0011eec] call_do_softirq+0x14/0x24
 312 [c042fe60] [c0006d78] do_softirq+0x84/0xa8
 313 [c042fe80] [c00314cc] irq_exit+0x88/0xb4
 314 [c042fe90] [c0006efc] do_IRQ+0xe0/0x234
 315 [c042fec0] [c0012bbc] ret_from_except+0x0/0x14
 316 --- Exception: 501 at cpu_idle+0xfc/0x10c
 317     LR = cpu_idle+0xfc/0x10c
 318 [c042ff80] [c000afb8] cpu_idle+0x68/0x10c (unreliable)
 319 [c042ffa0] [c0003ec0] rest_init+0x9c/0xbc
 320 [c042ffc0] [c03da91c] start_kernel+0x2c0/0x2d8
 321 [c042fff0] [00003438] 0x3438
 322 ** First patch
 323 diff --git a/net/can/gw.c b/net/can/gw.c
 324 index 94ba3f1..7779ca6 100644
 325 --- a/net/can/gw.c
 326 +++ b/net/can/gw.c
 327 @@ -822,11 +822,14 @@ static int cgw_create_job(struct sk_buff *skb,  struct nlmsghdr *nlh,
 328         if (gwj->dst.dev->type != ARPHRD_CAN)
 329                 goto put_src_dst_out;
 330
 331 -       spin_lock(&cgw_list_lock);
 332
 333         err = cgw_register_filter(gwj);
 334 -       if (!err)
 335 -               hlist_add_head_rcu(&gwj->list, &cgw_list);
 336 +       if (err)
 337 +               goto put_src_dst_out;
 338 +
 339 +       spin_lock(&cgw_list_lock);
 340 +
 341 +       hlist_add_head_rcu(&gwj->list, &cgw_list);
 342
 343         spin_unlock(&cgw_list_lock);
 344
 345 ** GFP_ATOMIC patch
 346 diff --git a/net/can/af_can.c b/net/can/af_can.c
 347 index 702be5a..b046ff0 100644
 348 --- a/net/can/af_can.c
 349 +++ b/net/can/af_can.c
 350 @@ -418,7 +418,7 @@ int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask,
 351         if (dev && dev->type != ARPHRD_CAN)
 352                 return -ENODEV;
 353
 354 -       r = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
 355 +       r = kmem_cache_alloc(rcv_cache, GFP_ATOMIC);
 356         if (!r)
 357                 return -ENOMEM;
 358
 359
 360
 361 ** Another panic
 362 BUG: spinlock bad magic on CPU#0, swapper/0
 363  lock: c7986abc, .magic: c0000000, .owner: <none>/-1, .owner_cpu: -1069424200
 364 Call Trace:
 365 [c7ffbd00] [c0009c04] show_stack+0xb0/0x1d4 (unreliable)
 366 [c7ffbd50] [c02ffe54] dump_stack+0x2c/0x44
 367 [c7ffbd60] [c01afa50] spin_bug+0x84/0xd0
 368 [c7ffbd80] [c01afbfc] do_raw_spin_lock+0x3c/0x15c
 369 [c7ffbdb0] [c02ff70c] _raw_spin_lock+0x34/0x4c
 370 [c7ffbdd0] [c025bbdc] dev_queue_xmit+0xa4/0x428
 371 [c7ffbe00] [c02d630c] can_send+0x9c/0x1a0
 372 [c7ffbe20] [c02d991c] can_can_gw_rcv+0x108/0x164
 373 [c7ffbe50] [c02d53b4] can_rcv_filter+0xf8/0x2e8
 374 [c7ffbe70] [c02d566c] can_rcv+0xc8/0x140
 375 [c7ffbe90] [c025a0d0] __netif_receive_skb+0x2cc/0x338
 376 [c7ffbed0] [c025a314] netif_receive_skb+0x5c/0x98
 377 [c7ffbef0] [c0208374] mscan_rx_poll+0x1c0/0x454
 378 [c7ffbf50] [c025a644] net_rx_action+0x104/0x230
 379 [c7ffbfa0] [c00317a8] __do_softirq+0x118/0x22c
 380 [c7ffbff0] [c0011eec] call_do_softirq+0x14/0x24
 381 [c042fe60] [c0006d78] do_softirq+0x84/0xa8
 382 [c042fe80] [c00314cc] irq_exit+0x88/0xb4
 383 [c042fe90] [c0006efc] do_IRQ+0xe0/0x234
 384 [c042fec0] [c0012bbc] ret_from_except+0x0/0x14
 385 --- Exception: 501 at cpu_idle+0xfc/0x10c
 386     LR = cpu_idle+0xfc/0x10c
 387 [c042ff80] [c000afb8] cpu_idle+0x68/0x10c (unreliable)
 388 [c042ffa0] [c0003ec0] rest_init+0x9c/0xbc
 389 [c042ffc0] [c03da91c] start_kernel+0x2c0/0x2d8
 390 [c042fff0] [00003438] 0x3438
 391 Unrecoverable FP Unavailable Exception 801 at c7986ca0
 392 Oops: Unrecoverable FP Unavailable Exception, sig: 6 [#1]
 393 PREEMPT Shark
 394 last sysfs file: /sys/devices/lpb.0/fc000000.flash/mtd/mtd2ro/dev
 395 Modules linked in:
 396 NIP: c7986ca0 LR: c025bc3c CTR: c7986ca0
 397 REGS: c7ffbd20 TRAP: 0801   Not tainted  (2.6.36.1-00006-g2e11adb-dirty)
 398 MSR: 00009032 <EE,ME,IR,DR>  CR: 22002024  XER: 2000005f
 399 TASK = c0411520[0] 'swapper' THREAD: c042e000
 400 GPR00: c7986ca0 c7ffbdd0 c0411520 c79b8240 c7986a60 00000010 c043b384 00004000
 401 GPR08: c043b788 00000000 00003fff c7ffbdd0 42002024
 402 NIP [c7986ca0] 0xc7986ca0
 403 LR [c025bc3c] dev_queue_xmit+0x104/0x428
 404 Call Trace:
 405 [c7ffbdd0] [c025bbdc] dev_queue_xmit+0xa4/0x428 (unreliable)
 406 [c7ffbe00] [c02d630c] can_send+0x9c/0x1a0
 407 [c7ffbe20] [c02d991c] can_can_gw_rcv+0x108/0x164
 408 [c7ffbe50] [c02d53b4] can_rcv_filter+0xf8/0x2e8
 409 [c7ffbe70] [c02d566c] can_rcv+0xc8/0x140
 410 [c7ffbe90] [c025a0d0] __netif_receive_skb+0x2cc/0x338
 411 [c7ffbed0] [c025a314] netif_receive_skb+0x5c/0x98
 412 [c7ffbef0] [c0208374] mscan_rx_poll+0x1c0/0x454
 413 [c7ffbf50] [c025a644] net_rx_action+0x104/0x230
 414 [c7ffbfa0] [c00317a8] __do_softirq+0x118/0x22c
 415 [c7ffbff0] [c0011eec] call_do_softirq+0x14/0x24
 416 [c042fe60] [c0006d78] do_softirq+0x84/0xa8
 417 [c042fe80] [c00314cc] irq_exit+0x88/0xb4
 418 [c042fe90] [c0006efc] do_IRQ+0xe0/0x234
 419 [c042fec0] [c0012bbc] ret_from_except+0x0/0x14
 420 --- Exception: 501 at cpu_idle+0xfc/0x10c
 421     LR = cpu_idle+0xfc/0x10c
 422 [c042ff80] [c000afb8] cpu_idle+0x68/0x10c (unreliable)
 423 [c042ffa0] [c0003ec0] rest_init+0x9c/0xbc
 424 [c042ffc0] [c03da91c] start_kernel+0x2c0/0x2d8
 425 [c042fff0] [00003438] 0x3438
 426 Instruction dump:
 427 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
 428 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
 429 Kernel panic - not syncing: Fatal exception in interrupt
 430 Call Trace:
 431 [c7ffbc10] [c0009c04] show_stack+0xb0/0x1d4 (unreliable)
 432 [c7ffbc60] [c02ffe54] dump_stack+0x2c/0x44
 433 [c7ffbc70] [c02fff28] panic+0xbc/0x200
 434 [c7ffbcd0] [c000faf8] die+0x1a4/0x1cc
 435 [c7ffbcf0] [c000fc34] kernel_fp_unavailable_exception+0x4c/0x64
 436 [c7ffbd10] [c0012bbc] ret_from_except+0x0/0x14
 437 --- Exception: 801 at 0xc7986ca0
 438     LR = dev_queue_xmit+0x104/0x428
 439 [c7ffbdd0] [c025bbdc] dev_queue_xmit+0xa4/0x428 (unreliable)
 440 [c7ffbe00] [c02d630c] can_send+0x9c/0x1a0
 441 [c7ffbe20] [c02d991c] can_can_gw_rcv+0x108/0x164
 442 [c7ffbe50] [c02d53b4] can_rcv_filter+0xf8/0x2e8
 443 [c7ffbe70] [c02d566c] can_rcv+0xc8/0x140
 444 [c7ffbe90] [c025a0d0] __netif_receive_skb+0x2cc/0x338
 445 [c7ffbed0] [c025a314] netif_receive_skb+0x5c/0x98
 446 [c7ffbef0] [c0208374] mscan_rx_poll+0x1c0/0x454
 447 [c7ffbf50] [c025a644] net_rx_action+0x104/0x230
 448 [c7ffbfa0] [c00317a8] __do_softirq+0x118/0x22c
 449 [c7ffbff0] [c0011eec] call_do_softirq+0x14/0x24
 450 [c042fe60] [c0006d78] do_softirq+0x84/0xa8
 451 [c042fe80] [c00314cc] irq_exit+0x88/0xb4
 452 [c042fe90] [c0006efc] do_IRQ+0xe0/0x234
 453 [c042fec0] [c0012bbc] ret_from_except+0x0/0x14
 454 --- Exception: 501 at cpu_idle+0xfc/0x10c
 455     LR = cpu_idle+0xfc/0x10c
 456 [c042ff80] [c000afb8] cpu_idle+0x68/0x10c (unreliable)
 457 [c042ffa0] [c0003ec0] rest_init+0x9c/0xbc
 458 [c042ffc0] [c03da91c] start_kernel+0x2c0/0x2d8
 459 [c042fff0] [00003438] 0x3438
 460
 461
 462 * write returns ENOBUFS
 463 The reason is queuing discipline - the queue is full and
 464 pfifo_fast_enqueue returns failure. This failure is propagated down to
 465 qdisc_enqueue_root(), __dev_xmit_skb(), dev_queue_xmit() and
 466 can_send()
 467
 468 ** See the follwing trace
 469
 470 # tracer: function_graph
 471 #
 472 # CPU  DURATION                  FUNCTION CALLS
 473 # |     |   |                     |   |   |   |
 474  1)               |  can_send() {
 475  1)               |    dev_queue_xmit() {
 476  1)               |      rt_spin_lock() {
 477  1)   0.894 us    |        __might_sleep();
 478  1)   2.750 us    |      }
 479  1)               |      pfifo_fast_enqueue() {
 480  1)               |        kfree_skb() {
 481  1)               |          __kfree_skb() {
 482  1)               |            skb_release_head_state() {
 483  1)               |              sock_wfree() {
 484  1)               |                sock_def_write_space() {
 485  1)               |                  rt_read_lock() {
 486  1)               |                    __rt_spin_lock() {
 487  1)   0.677 us    |                      __might_sleep();
 488  1)   2.386 us    |                    }
 489  1)   4.150 us    |                  }
 490  1)               |                  rt_read_unlock() {
 491  1)   0.918 us    |                    __rt_spin_unlock();
 492  1)   2.644 us    |                  }
 493  1)   9.375 us    |                }
 494  1) + 10.999 us   |              }
 495  1) + 12.708 us   |            }
 496  1)               |            skb_release_data() {
 497  1)               |              kfree() {
 498  1)               |                _slab_irq_disable() {
 499  1)               |                  rt_spin_lock() {
 500  1)   0.849 us    |                    __might_sleep();
 501  1)   2.588 us    |                  }
 502  1)   4.242 us    |                }
 503  1)   0.864 us    |                __cache_free();
 504  1)   0.888 us    |                rt_spin_unlock();
 505  1)   9.456 us    |              }
 506  1) + 11.185 us   |            }
 507  1)               |            kmem_cache_free() {
 508  1)               |              _slab_irq_disable() {
 509  1)               |                rt_spin_lock() {
 510  1)   0.812 us    |                  __might_sleep();
 511  1)   2.542 us    |                }
 512  1)   4.240 us    |              }
 513  1)   0.813 us    |              __cache_free();
 514  1)   0.894 us    |              rt_spin_unlock();
 515  1)   9.329 us    |            }
 516  1) + 36.444 us   |          }
 517  1) + 38.136 us   |        }
 518  1) + 39.974 us   |      }
 519  1)               |      /* qdisc_enqueue_root = 1 */
 520  1)               |      __qdisc_run() {
 521  1)               |        sch_direct_xmit() {
 522  1)   0.855 us    |          rt_spin_unlock();
 523  1)               |          rt_spin_lock() {
 524  1)   0.827 us    |            __might_sleep();
 525  1)   2.521 us    |          }
 526  1)               |          dev_hard_start_xmit() {
 527  1)               |            sja1000_start_xmit() {
 528  1)   1.646 us    |              kvaser_pci_write_reg();
 529  1)   1.460 us    |              kvaser_pci_write_reg();
 530  1)   1.691 us    |              kvaser_pci_write_reg();
 531  1)   1.450 us    |              kvaser_pci_write_reg();
 532  1)   1.416 us    |              kvaser_pci_write_reg();
 533  1)               |              can_put_echo_skb() {
 534  1)               |                sock_wfree() {
 535  1)               |                  sock_def_write_space() {
 536  1)               |                    rt_read_lock() {
 537  1)               |                      __rt_spin_lock() {
 538  1)   0.939 us    |                        __might_sleep();
 539  1)   2.699 us    |                      }
 540  1)   4.337 us    |                    }
 541  1)               |                    rt_read_unlock() {
 542  1)   0.844 us    |                      __rt_spin_unlock();
 543  1)   2.507 us    |                    }
 544  1)   9.242 us    |                  }
 545  1) + 11.047 us   |                }
 546  1) + 12.791 us   |              }
 547  1)               |              sja1000_write_cmdreg() {
 548  1)               |                rt_spin_lock() {
 549  1)   0.802 us    |                  __might_sleep();
 550  1)   2.532 us    |                }
 551  1)   1.481 us    |                kvaser_pci_write_reg();
 552  1)   2.155 us    |                kvaser_pci_read_reg();
 553  1)   0.843 us    |                rt_spin_unlock();
 554  1) + 11.100 us   |              }
 555  1) + 38.263 us   |            }
 556  1)               |            /* ops->ndo_start_xmit(skb, dev) = 0 */
 557  1) + 41.508 us   |          }
 558  1)               |          /* dev_hard_start_xmit(skb, dev) = 0 */
 559  1)   0.884 us    |          rt_spin_unlock();
 560  1)               |          rt_spin_lock() {
 561  1)   0.817 us    |            __might_sleep();
 562  1)   2.583 us    |          }
 563  1)               |          /* qdisc_len = 9 */
 564  1)               |          /* sch_direct_xmit returns 0 */
 565  1) + 57.502 us   |        }
 566  1) + 59.288 us   |      }
 567  1)   0.877 us    |      rt_spin_unlock();
 568  1)               |      /* __dev_xmit_skb = 1 */
 569  1) ! 111.265 us  |    }
 570  1)               |  /* dev_queue_xmit = 1 */
 571  1)               |  /* net_xmit_errno = -105 */
 572  1)   0.956 us    |    kfree_skb();
 573  1) ! 117.340 us  |  }
 574  1)               |  /* write returned -1 */
 575
 576 ** The trace was generated by kernel v2.6.33.7-rt29-4-g92487e4 with the following patch applied:
 577
 578 diff --git a/net/can/af_can.c b/net/can/af_can.c
 579 index 4d8479d7..c91968d 100644
 580 --- a/net/can/af_can.c
 581 +++ b/net/can/af_can.c
 582 @@ -344,8 +344,11 @@ int can_send(struct sk_buff *skb, int loop)
 583
 584         /* send to netdevice */
 585         err = dev_queue_xmit(skb);
 586 -       if (err > 0)
 587 +       trace_printk("dev_queue_xmit = %d\n", err);
 588 +       if (err > 0) {
 589                 err = net_xmit_errno(err);
 590 +               trace_printk("net_xmit_errno = %d\n", err);
 591 +       }
 592
 593         if (err) {
 594  #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,17)
 595 diff --git a/net/core/dev.c b/net/core/dev.c
 596 index 7a5412e..10ca9b4 100644
 597 --- a/net/core/dev.c
 598 +++ b/net/core/dev.c
 599 @@ -1828,6 +1828,8 @@ int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
 600                         skb_dst_drop(skb);
 601
 602                 rc = ops->ndo_start_xmit(skb, dev);
 603 +               trace_printk("ops->ndo_start_xmit(skb, dev) = %d\n", rc);
 604 +
 605                 if (rc == NETDEV_TX_OK)
 606                         txq_trans_update(txq);
 607                 /*
 608 @@ -1854,6 +1856,7 @@ gso:
 609                 skb->next = nskb->next;
 610                 nskb->next = NULL;
 611                 rc = ops->ndo_start_xmit(nskb, dev);
 612 +               trace_printk("gso: ops->ndo_start_xmit(skb, dev) = %d\n", rc);
 613                 if (unlikely(rc != NETDEV_TX_OK)) {
 614                         if (rc & ~NETDEV_TX_MASK)
 615                                 goto out_kfree_gso_skb;
 616 @@ -1949,6 +1952,8 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
 617         spin_lock(root_lock);
 618         if (unlikely(test_bit(__QDISC_STATE_DEACTIVATED, &q->state))) {
 619                 kfree_skb(skb);
 620 +               trace_printk("QDISC_STATE_DEACTIVATED\n");
 621 +
 622                 rc = NET_XMIT_DROP;
 623         } else if ((q->flags & TCQ_F_CAN_BYPASS) && !qdisc_qlen(q) &&
 624                    !test_and_set_bit(__QDISC_STATE_RUNNING, &q->state)) {
 625 @@ -1966,6 +1971,7 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
 626                 rc = NET_XMIT_SUCCESS;
 627         } else {
 628                 rc = qdisc_enqueue_root(skb, q);
 629 +               trace_printk("qdisc_enqueue_root = %d\n", rc);
 630                 qdisc_run(q);
 631         }
 632         spin_unlock(root_lock);
 633 @@ -2047,6 +2053,7 @@ gso:
 634  #endif
 635         if (q->enqueue) {
 636                 rc = __dev_xmit_skb(skb, q, dev, txq);
 637 +               trace_printk("__dev_xmit_skb = %d\n", rc);
 638                 goto out;
 639         }
 640
 641 @@ -2072,6 +2079,8 @@ gso:
 642
 643                         if (!netif_tx_queue_stopped(txq)) {
 644                                 rc = dev_hard_start_xmit(skb, dev, txq);
 645 +                               trace_printk("dev_hard_start_xmit = %d\n", rc);
 646 +
 647                                 if (dev_xmit_complete(rc)) {
 648                                         HARD_TX_UNLOCK(dev, txq);
 649                                         goto out;
 650 diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
 651 index bf7f50e..aea0833 100644
 652 --- a/net/sched/sch_generic.c
 653 +++ b/net/sched/sch_generic.c
 654 @@ -125,6 +125,7 @@ int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
 655         HARD_TX_LOCK(dev, txq);
 656         if (!netif_tx_queue_stopped(txq) && !netif_tx_queue_frozen(txq))
 657                 ret = dev_hard_start_xmit(skb, dev, txq);
 658 +       trace_printk("dev_hard_start_xmit(skb, dev) = %d\n", ret);
 659
 660         HARD_TX_UNLOCK(dev, txq);
 661
 662 @@ -133,9 +134,11 @@ int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
 663         if (dev_xmit_complete(ret)) {
 664                 /* Driver sent out skb successfully or skb was consumed */
 665                 ret = qdisc_qlen(q);
 666 +               trace_printk("qdisc_len = %d\n", ret);
 667         } else if (ret == NETDEV_TX_LOCKED) {
 668                 /* Driver try lock failed */
 669                 ret = handle_dev_cpu_collision(skb, txq, q);
 670 +               trace_printk("handle_dev_cpu_collision = %d\n", ret);
 671         } else {
 672                 /* Driver returned NETDEV_TX_BUSY - requeue skb */
 673                 if (unlikely (ret != NETDEV_TX_BUSY && net_ratelimit()))
 674 @@ -143,12 +146,13 @@ int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
 675                                dev->name, ret, q->q.qlen);
 676
 677                 ret = dev_requeue_skb(skb, q);
 678 +               trace_printk("dev_requeue_skb = %d\n", ret);
 679         }
 680
 681         if (ret && (netif_tx_queue_stopped(txq) ||
 682                     netif_tx_queue_frozen(txq)))
 683                 ret = 0;
 684 -
 685 +       trace_printk("%s returns %d\n", __FUNCTION__, ret);
 686         return ret;
 687  }
 688