kernel panic in skb_push when using d_can can0 interface and networking

Adri G

We're seeing a crash of the kernel due to skb_push() failing a check in Linux kernel 3.2. This seems to happen because of some cross-over from d_can packets on can0 interface when using dhclient application.

I've tried to do a workaround in dhclient application by modifying next_iface4() function in common/discover.c of dhcp-4.2.3-P1, basically not to add can0 interface to the list of interfaces. This seemed to reduce number of crashes but hasn't eliminated them.

[ 3605.118530] dhclient[2040]: Bound to *:546
[ 3665.425997] packet_rcv_spkt: header( (null)) < head(cf3d8a00).
[ 3665.445946] packet_rcv_spkt: data (cf3d8a40)
[ 3665.517431] skb_under_panic: text:c03cb6a8 len:-818050480 put:-818050496 head:cf3d8a00 data: (null) tail:0xcf3d8a50 end:0xcf3d8b40 dev:can0
[ 3665.556441] ------------[ cut here ]------------
[ 3665.570671] kernel BUG at net/core/skbuff.c:147!
[ 3665.584899] Internal error: Oops - undefined instruction: 0 [#1]
[ 3665.603417] Modules linked in:
[ 3665.612826] CPU: 0    Not tainted (3.2.0-ts-armv7l #479)
[ 3665.629489] PC is at skb_push+0x74/0x80
[ 3665.641312] LR is at console_unlock+0x16c/0x1f8
[ 3665.655276] pc : [<c031d954>]    lr : [<c003a2ec>]    psr: 600f0113
[ 3665.655284] sp : cfa09c78 ip : cfa09b88 fp : cfa09ca4
[ 3665.690697] r10: 00000000 r9 : c0d0e6d8 r8 : 00000c00
[ 3665.706802] r7 : ced42800 r6 : ce9b4c00 r5 : cf3d8a50 r4 : c052a93c
[ 3665.726931] r3 : c0d2c254 r2 : c0d2c254 r1 : 00000000 r0 : 00000096
[ 3665.747063] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
[ 3665.769071] Control: 10c5387d Table: 8e9b0019 DAC: 00000015
[ 3665.786785] Process dhclient (pid: 2053, stack limit = 0xcfa082e8)
[ 3665.805840] Stack: (0xcfa09c78 to 0xcfa0a000)
[ 3665.819266] 9c60:                                                       cf3d8a00 00000000
[ 3665.844498] 9c80: cf3d8a50 cf3d8b40 ced42800 cfa09ca8 cea1a600 ced42800 cfa09cc4 cfa09ca8
[ 3665.869731] 9ca0: c03cb6a8 c031d8ec ced42800 cea1af00 c0d10db8 c0d0e6d0 cfa09d0c cfa09cc8
[ 3665.894966] 9cc0: c0324ff4 c03cb5d0 00000003 00000020 00730003 cea1af00 20302e30 c0d10dd8
[ 3665.920198] 9ce0: cfa09d0c cea1af00 00000003 00000020 00730003 0000b408 20302e30 cea1af00
[ 3665.945430] 9d00: cfa09d2c cfa09d10 c032525c c0324d08 1f892d5c 0d234ce7 ced42800 ced42800
[ 3665.970661] 9d20: cfa09d74 cfa09d30 c0266864 c0325220 00000020 ced42c24 20302e30 00000000
[ 3665.995893] 9d40: 00000041 cf3d8a40 cfa09dcc c0266494 ced42c24 00000020 0000012c c0d5a780
[ 3666.021123] 9d60: c0d5a780 c0d2d2b0 cfa09dac cfa09d78 c0327428 c02664a0 c0d5a788 000522a0
[ 3666.046356] 9d80: cfa09dc4 00000001 0000000c c0d6c594 c0d6c584 cfa08000 00000003 00000100
[ 3666.071586] 9da0: cfa09dec cfa09db0 c003ed4c c0327390 cfa08000 00000000 cfa09ddc 0000000a
[ 3666.096818] 9dc0: c006e4fc cfa08000 00000034 00000000 cfa09e74 c00141a8 cfa08000 00000000
[ 3666.122049] 9de0: cfa09e04 cfa09df0 c003f190 c003ecb8 c00702f4 c0d3e038 cfa09e24 cfa09e08
[ 3666.147280] 9e00: c0014ee0 c003f114 00000034 fa200000 cfa09e40 ffffffff cfa09e3c cfa09e28
[ 3666.172512] 9e20: c00086c8 c0014eb0 c032489c 600f0013 cfa09e94 cfa09e40 c0013c40 c0008684
[ 3666.197743] 9e40: ce9b4ec0 ce9b4ec0 00000300 00000300 ce9b4c00 00000000 beb4db70 0000011a
[ 3666.222974] 9e60: c00141a8 cfa08000 00000000 cfa09e94 cfa09e98 cfa09e88 c03ca0e0 c032489c
[ 3666.248207] 9e80: 600f0013 ffffffff cfa09eb4 cfa09e98 c03ca0e0 c0324830 c0318d9c 00000001
[ 3666.273437] 9ea0: ce801800 ce9b4c00 cfa09ed4 cfa09eb8 c03ccbd4 c03ca02c cfa09ed4 00000300
[ 3666.298668] 9ec0: ce9b4c00 00000010 cfa09efc cfa09ed8 c03ccc70 c03ccaf0 68746510 00000030
[ 3666.323900] 9ee0: beb4db70 c0317290 ce998940 cf455e40 cfa09fa4 cfa09f00 c03174dc c03ccc24
[ 3666.349130] 9f00: 00000000 00000000 74650011 00003068 00000000 00000000 cfa09f64 cfa09f28
[ 3666.374360] 9f20: c0316348 c00a10e8 cfa09f64 cf8105c0 cf479698 00000000 00000000 c04f3e28
[ 3666.399591] 9f40: 00e9b5a8 0000000a 00000000 00000004 00000119 c00141a8 cfa09f84 cfa09f68
[ 3666.424821] 9f60: c03163ec c009e3f0 cfa09f8c ce998940 cfa5ba00 0000000a cfa09fa4 cfa09f88
[ 3666.450053] 9f80: c03172f8 c03163cc cfa08000 00e9b5a8 00000006 00000004 00000000 cfa09fa8
[ 3666.475284] 9fa0: c0014000 c0317484 00e9b5a8 00000006 00000006 beb4db70 00000010 beb4db7f
[ 3666.500515] 9fc0: 00e9b5a8 00000006 00000004 0000011a 00000000 00000004 00000010 00000001
[ 3666.525746] 9fe0: 0012e8ac beb4db6c 0002a124 4018984c 600f0010 00000006 00000000 00000000
[ 3666.550968] Backtrace:
[ 3666.558521] [<c031d8e0>] (skb_push+0x0/0x80) from [<c03cb6a8>] (packet_rcv_spkt+0xe4/0x1ac)
[ 3666.584281] r5:ced42800 r4:cea1a600
[ 3666.595314] [<c03cb5c4>] (packet_rcv_spkt+0x0/0x1ac) from [<c0324ff4>] (__netif_receive_skb+0x2f8/0x3dc)
[ 3666.624560] r6:c0d0e6d0 r5:c0d10db8 r4:cea1af00 r3:ced42800
[ 3666.642040] [<c0324cfc>] (__netif_receive_skb+0x0/0x3dc) from [<c032525c>] (netif_receive_skb+0x48/0x6c)
[ 3666.671304] [<c0325214>] (netif_receive_skb+0x0/0x6c) from [<c0266864>] (d_can_poll+0x3d0/0x720)
[ 3666.698405] r4:ced42800
[ 3666.706208] [<c0266494>] (d_can_poll+0x0/0x720) from [<c0327428>] (net_rx_action+0xa4/0x188)
[ 3666.732251] [<c0327384>] (net_rx_action+0x0/0x188) from [<c003ed4c>] (__do_softirq+0xa0/0x13c)
[ 3666.758826] [<c003ecac>] (__do_softirq+0x0/0x13c) from [<c003f190>] (irq_exit+0x88/0x90)
[ 3666.783806] [<c003f108>] (irq_exit+0x0/0x90) from [<c0014ee0>] (handle_IRQ+0x3c/0x8c)
[ 3666.807956] r4:c0d3e038 r3:c00702f4
[ 3666.818981] [<c0014ea4>] (handle_IRQ+0x0/0x8c) from [<c00086c8>] (omap3_intc_handle_irq+0x50/0x54)
[ 3666.846618] r6:ffffffff r5:cfa09e40 r4:fa200000 r3:00000034
[ 3666.864095] [<c0008678>] (omap3_intc_handle_irq+0x0/0x54) from [<c0013c40>] (__irq_svc+0x40/0x60)
[ 3666.891464] Exception stack(0xcfa09e40 to 0xcfa09e88)
[ 3666.907039] 9e40: ce9b4ec0 ce9b4ec0 00000300 00000300 ce9b4c00 00000000 beb4db70 0000011a
[ 3666.932271] 9e60: c00141a8 cfa08000 00000000 cfa09e94 cfa09e98 cfa09e88 c03ca0e0 c032489c
[ 3666.957495] 9e80: 600f0013 ffffffff
[ 3666.968232] r5:600f0013 r4:c032489c
[ 3666.979258] [<c0324824>] (__dev_remove_pack+0x0/0x98) from [<c03ca0e0>] (__unregister_prot_hook+0xc0/0xc8)
[ 3667.009052] [<c03ca020>] (__unregister_prot_hook+0x0/0xc8) from [<c03ccbd4>] (packet_do_bind+0xf0/0x134)
[ 3667.038298] r5:ce9b4c00 r4:ce801800
[ 3667.049327] [<c03ccae4>] (packet_do_bind+0x0/0x134) from [<c03ccc70>] (packet_bind_spkt+0x58/0x64)
[ 3667.076963] r5:00000010 r4:ce9b4c00
[ 3667.087988] [<c03ccc18>] (packet_bind_spkt+0x0/0x64) from [<c03174dc>] (sys_bind+0x64/0x8c)
[ 3667.113747] r4:cf455e40
[ 3667.121549] [<c0317478>] (sys_bind+0x0/0x8c) from [<c0014000>] (ret_fast_syscall+0x0/0x30)
[ 3667.147040] r6:00000004 r5:00000006 r4:00e9b5a8
[ 3667.161289] Code: 01a0c004 e59f000c e58dc010 eb037e77 (e7f001f2)
[ 3667.180179] ---[ end trace b93eb1e0b7c40a12 ]---
[ 3667.194430] Kernel panic - not syncing: Fatal exception in interrupt
[ 3667.214036] Backtrace:
[ 3667.221594] [<c00175e4>] (dump_backtrace+0x0/0x10c) from [<c03fcedc>] (dump_stack+0x18/0x1c)
[ 3667.247637] r6:00000000 r5:cfa08000 r4:c0d5bc08 r3:c0d2c254
[ 3667.265138] [<c03fcec4>] (dump_stack+0x0/0x1c) from [<c03fd20c>] (panic+0x64/0x18c)
[ 3667.288775] [<c03fd1a8>] (panic+0x0/0x18c) from [<c00178cc>] (die+0x128/0x264)
[ 3667.311064] r3:00000100 r2:00000000 r1:0000c806 r0:c04e2810
[ 3667.328563] r7:cfa09b2f
[ 3667.336379] [<c00177a4>] (die+0x0/0x264) from [<c0017a28>] (arm_notify_die+0x20/0x58)
[ 3667.360554] [<c0017a08>] (arm_notify_die+0x0/0x58) from [<c00084d8>] (do_undefinstr+0x104/0x110)
[ 3667.387681] [<c00083d4>] (do_undefinstr+0x0/0x110) from [<c0013ca8>] (__und_svc+0x48/0x60)
[ 3667.413189] Exception stack(0xcfa09c30 to 0xcfa09c78)
[ 3667.428776] 9c20:                                     00000096 00000000 c0d2c254 c0d2c254
[ 3667.454024] 9c40: c052a93c cf3d8a50 ce9b4c00 ced42800 00000c00 c0d0e6d8 00000000 cfa09ca4
[ 3667.479268] 9c60: cfa09b88 cfa09c78 c003a2ec c031d954 600f0113 ffffffff
[ 3667.499678] r8:e7100000 r7:00000000 r6:c0013f14 r5:600f0113 r4:c031d958
[ 3667.520409] [<c031d8e0>] (skb_push+0x0/0x80) from [<c03cb6a8>] (packet_rcv_spkt+0xe4/0x1ac)
[ 3667.546185] r5:ced42800 r4:cea1a600
[ 3667.557228] [<c03cb5c4>] (packet_rcv_spkt+0x0/0x1ac) from [<c0324ff4>] (__netif_receive_skb+0x2f8/0x3dc)
[ 3667.586490] r6:c0d0e6d0 r5:c0d10db8 r4:cea1af00 r3:ced42800
[ 3667.603993] [<c0324cfc>] (__netif_receive_skb+0x0/0x3dc) from [<c032525c>] (netif_receive_skb+0x48/0x6c)
[ 3667.633267] [<c0325214>] (netif_receive_skb+0x0/0x6c) from [<c0266864>] (d_can_poll+0x3d0/0x720)
[ 3667.660383] r4:ced42800
[ 3667.668200] [<c0266494>] (d_can_poll+0x0/0x720) from [<c0327428>] (net_rx_action+0xa4/0x188)
[ 3667.694255] [<c0327384>] (net_rx_action+0x0/0x188) from [<c003ed4c>] (__do_softirq+0xa0/0x13c)
[ 3667.720845] [<c003ecac>] (__do_softirq+0x0/0x13c) from [<c003f190>] (irq_exit+0x88/0x90)
[ 3667.745828] [<c003f108>] (irq_exit+0x0/0x90) from [<c0014ee0>] (handle_IRQ+0x3c/0x8c)
[ 3667.769994] r4:c0d3e038 r3:c00702f4
[ 3667.781035] [<c0014ea4>] (handle_IRQ+0x0/0x8c) from [<c00086c8>] (omap3_intc_handle_irq+0x50/0x54)
[ 3667.808686] r6:ffffffff r5:cfa09e40 r4:fa200000 r3:00000034
[ 3667.826187] [<c0008678>] (omap3_intc_handle_irq+0x0/0x54) from [<c0013c40>] (__irq_svc+0x40/0x60)
[ 3667.853572] Exception stack(0xcfa09e40 to 0xcfa09e88)
[ 3667.869161] 9e40: ce9b4ec0 ce9b4ec0 00000300 00000300 ce9b4c00 00000000 beb4db70 0000011a
[ 3667.894407] 9e60: c00141a8 cfa08000 00000000 cfa09e94 cfa09e98 cfa09e88 c03ca0e0 c032489c
[ 3667.919647] 9e80: 600f0013 ffffffff
[ 3667.930396] r5:600f0013 r4:c032489c
[ 3667.941438] [<c0324824>] (__dev_remove_pack+0x0/0x98) from [<c03ca0e0>] (__unregister_prot_hook+0xc0/0xc8)
[ 3667.971248] [<c03ca020>] (__unregister_prot_hook+0x0/0xc8) from [<c03ccbd4>] (packet_do_bind+0xf0/0x134)
[ 3668.000511] r5:ce9b4c00 r4:ce801800
[ 3668.011567] [<c03ccae4>] (packet_do_bind+0x0/0x134) from [<c03ccc70>] (packet_bind_spkt+0x58/0x64)
[ 3668.039219] r5:00000010 r4:ce9b4c00
[ 3668.050260] [<c03ccc18>] (packet_bind_spkt+0x0/0x64) from [<c03174dc>] (sys_bind+0x64/0x8c)
[ 3668.076033] r4:cf455e40
[ 3668.083848] [<c0317478>] (sys_bind+0x0/0x8c) from [<c0014000>] (ret_fast_syscall+0x0/0x30)
[ 3668.109353] r6:00000004 r5:00000006 r4:00e9b5a8

We haven't had this issue on other platforms, but we also didn't use the socket can interface (they used pcan). Wondering if anyone else has seen this issue or may know of a work-around.

Saw a similar issue on http://comments.gmane.org/gmane.linux.can/6078 but their workaround still didn't work for us. Even though I tried adding the skb_reset_mac_header(), something is setting the mac_header back to null....

over 9 years ago

0 Marcel Schmall over 6 years ago

Prodigy 10 points

Hey guys, I know this thread is quit old but I have a problem that looks equal to this. Since we use WIFI with our embedded Linux systems we detect some abrupt reboots. CAN-Bus devices from PEAK are part of the system. The Linux kernel is 3.0.0.

To get more information we recorded the standard output via serial interface. The logs show us that a kernel panic occurs that looks very similar to the panic in this thread.

Debian GNU/Linux[ 1257.200335] skb_under_panic: text:c126a86a len:-185846640 put:-185846656 head:f4ec3480 data: (null) tail:0xf4ec3490 end:0xf4ec34c0 dev:can1

6.0 DERUERL4214[ 1257.360139] ------------[ cut here ]------------

[ 1257.361010] kernel BUG at net/core/skbuff.c:147!

[ 1257.361010] invalid opcode: 0000 [#1] PREEMPT SMP

[ 1257.361010] Modules linked in: ipv6 uinput(O) rtc arc4 iwlagn ccd_dilog(O) usbhid mac80211 lpc_sch mfd_core cfg80211 poulsbo rfkill video evdev mmc_block ata_generic pata_sch libata uhci_hcd ehci_hcd usbcore sdhci_pci ide_pci_generic sdhci mmc_core r8169 mii [last unloaded: scsi_wait_scan]

[ 1257.361010]

[ 1257.361010] Pid: 2112, comm: Display Tainted: G           O 3.0.0-voyage-all-sysrq #1

[ 1257.361010] EIP: 0060:[<c120708c>] EFLAGS: 00013246 CPU: 0

[ 1257.361010] EIP is at skb_push+0x59/0x62

[ 1257.361010] EAX: 00000096 EBX: f5a71400 ECX: c1392a50 EDX: 00003046

[ 1257.361010] ESI: c126a86a EDI: f50e8c00 EBP: f600df4c ESP: f600df20

[ 1257.361010] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068

[ 1257.361010] Process Display (pid: 2112, ti=f600c000 task=f615b470 task.ti=f565a000)

[ 1257.361010] Stack:

[ 1257.361010] c1347fef c126a86a f4ec3490 f4ec3480 f4ec3480 00000000 f4ec3490 f4ec34c0

[ 1257.361010] f5a71400 f50e8c00 f5a71400 f600df64 c126a86a f515a000 f515a200 c13aea60

[ 1257.361010] 00000c00 f600df90 c120d54a f5a71400 c13ada08 f5a71400 00000000 f51350c0

[ 1257.361010] Call Trace:

[ 1257.361010] [<c126a86a>] ? packet_rcv_spkt+0xc1/0xff

[ 1257.361010] [<c126a86a>] packet_rcv_spkt+0xc1/0xff

[ 1257.361010] [<c120d54a>] __netif_receive_skb+0x30b/0x35f

[ 1257.361010] [<c120d5fd>] process_backlog+0x5f/0xf7

[ 1257.361010] [<c120dc8e>] net_rx_action+0x53/0xf3

[ 1257.361010] [<c1026218>] __do_softirq+0x6e/0xde

[ 1257.361010] [<c10261aa>] ? remote_softirq_receive+0x15/0x15

[ 1257.361010] <IRQ>

[ 1257.361010] [<c120bee5>] ? netif_rx_ni+0x25/0x40

[ 1257.361010] [<c126c97e>] ? can_send+0x108/0x11c

[ 1257.361010] [<c126da46>] ? raw_sendmsg+0xd9/0x113

[ 1257.361010] [<c11ffebc>] ? sock_aio_write+0xed/0xf6

[ 1257.361010] [<c107a4e7>] ? do_sync_write+0x8a/0xc5

[ 1257.361010] [<c107aae0>] ? vfs_write+0x9c/0xfe

[ 1257.361010] [<c107acd9>] ? sys_write+0x3b/0x60

[ 1257.361010] [<c129a9c5>] ? syscall_call+0x7/0xb

[ 1257.361010] [<c1290000>] ? get_cpu_leaves+0xeb/0x1ec

[ 1257.361010] Code: 02 89 d8 50 ff b1 a0 00 00 00 ff b1 9c 00 00 00 ff b1 a8 00 00 00 ff b1 a4 00 00 00 52 ff 71 50 56 68 ef 7f 34 c1 e8 57 f8 08 00 <0f> 0b 8d 65 f8 5b 5e 5d c3 55 89 c1 89 e5 56 53 8b 80 9c 00 00

[ 1257.361010] EIP: [<c120708c>] skb_push+0x59/0x62 SS:ESP 0068:f600df20

[ 1259.987735] ccd_dilog: rx buffer allocation failure: driver lost 1 frame (rx[count=400 total=9479591 w=391]

[ 1259.988414] ccd_dilog: message decoding error -12

[ 1259.988414] ccd_dilog: rx buffer allocation failure: driver lost 1 frame (rx[count=400 total=9479591 w=391]

[ 1259.988414] ccd_dilog: rx buffer allocation failure: driver lost 1 frame (rx[count=400 total=9479591 w=391]

ttyS0

[ 1260.394091] ---[ end trace 81aa61bf964f094c ]---

[ 1260.459743] Kernel panic - not syncing: Fatal exception in interrupt

[ 1260.535996] Pid: 2112, comm: Display Tainted: G     D   O 3.0.0-voyage-all-sysrq #1

[ 1260.629807] ccd_dilog: rx buffer allocation failure: driver lost 1 frame (rx[count=400 total=9479591 w=391]

[ 1260.746626] Call Trace:

[ 1260.775982] [<c1296803>] panic+0x58/0x138

[ 1260.825173] [<c1004883>] oops_end+0x6e/0x7c

[ 1260.876475] [<c10049b9>] die+0x51/0x58

[ 1260.922524] [<c1002681>] do_trap+0x89/0xa2

[ 1260.972787] [<c10027b6>] ? do_bounds+0x52/0x52

[ 1261.027155] [<c1002827>] do_invalid_op+0x71/0x7b

[ 1261.083682] [<c120708c>] ? skb_push+0x59/0x62

[ 1261.136995] [<c129b769>] ? common_interrupt+0x29/0x30

[ 1261.198745] [<c102007b>] ? sched_rt_handler+0xd4/0x159

[ 1261.261370] [<c1022f16>] ? vprintk+0x30d/0x346

[ 1261.315842] [<c126a86a>] ? packet_rcv_spkt+0xc1/0xff

[ 1261.376441] [<c129af9a>] error_code+0x5a/0x60

[ 1261.429699] iwlagn 0000:01:00.0: Error sending REPLY_QOS_PARAM: time out after 500ms.

[ 1261.429799] [<c126a86a>] ? packet_rcv_spkt+0xc1/0xff

[ 1261.429836] [<c126007b>] ? xfrm_policy_flush+0x68/0x10d

[ 1261.429845] [<c10027b6>] ? do_bounds+0x52/0x52

[ 1261.429854] [<c120708c>] ? skb_push+0x59/0x62

[ 1261.429862] [<c126a86a>] ? packet_rcv_spkt+0xc1/0xff

[ 1261.429870] [<c126a86a>] packet_rcv_spkt+0xc1/0xff

[ 1261.429879] [<c120d54a>] __netif_receive_skb+0x30b/0x35f

[ 1261.429888] [<c120d5fd>] process_backlog+0x5f/0xf7

[ 1261.429896] [<c120dc8e>] net_rx_action+0x53/0xf3

[ 1261.429906] [<c1026218>] __do_softirq+0x6e/0xde

[ 1261.429915] [<c10261aa>] ? remote_softirq_receive+0x15/0x15

[ 1261.429920] <IRQ> [<c120bee5>] ? netif_rx_ni+0x25/0x40

[ 1261.429933] [<c126c97e>] ? can_send+0x108/0x11c

[ 1261.429941] [<c126da46>] ? raw_sendmsg+0xd9/0x113

[ 1261.429951] [<c11ffebc>] ? sock_aio_write+0xed/0xf6

[ 1261.429962] [<c107a4e7>] ? do_sync_write+0x8a/0xc5

[ 1261.429972] [<c107aae0>] ? vfs_write+0x9c/0xfe

[ 1261.429980] [<c107acd9>] ? sys_write+0x3b/0x60

[ 1261.429989] [<c129a9c5>] ? syscall_call+0x7/0xb

[ 1261.429998] [<c1290000>] ? get_cpu_leaves+0xeb/0x1ec

[ 1262.596821] Rebooting in 30 seconds..

[ 1262.597007] ACPI MEMORY or I/O RESET_REG.

We try to find out what exactly trigged the panic. It seems to be triggered by skb_push, a function that change the content of a socked buffer. The data pointer is NULL what is the reason why skb_push jumps in skb_under_panic.

unsigned char *skb_push(struct sk_buff *skb, unsigned int len)

{

skb->data -= len;

skb->len += len;

if (unlikely(skb->data<skb->head))

skb_under_panic(skb, len, __builtin_return_address(0));

return skb->data;

}

Because the data pointer is NULL the length and put variable become negative. But I don’t know what part of the kernel is trigger this function and why the pointer point to NULL.

I look in the source of our CAN driver and didn’t find skb_push. The driver only use skb_put.

My question are:

Is this failure known?
What part of the kernel trigger the failure and why?
Why the data pointer could be points to NULL?
Is the failure maybe fix in newer kernel version?

I’m still learning about the Linux kernel so every hint will be welcome.

Thank you for your time and best regards

Marcel

0 Yordan Kovachev over 6 years ago in reply to Marcel Schmall

TI__Guru**** 161600 points

Which processor is this?

Processors

Processors forum

kernel panic in skb_push when using d_can can0 interface and networking