Will be happy if someone can give me some more insight. (kernel 2.6.37-rc5)
Thanks
Tomas
Dec 15 14:36:41 User-PC kernel: [175576.120287] ------------[ cut here
]------------
Dec 15 14:36:41 User-PC kernel: [175576.120452] kernel BUG at
include/linux/skbuff.h:1178!
Dec 15 14:36:41 User-PC kernel: [175576.120609] invalid opcode: 0000 [#1] SMP
Dec 15 14:36:41 User-PC kernel: [175576.120749] last sysfs file:
/sys/devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0/block/sda/uevent
Dec 15 14:36:41 User-PC kernel: [175576.121035] Modules linked in:
oprofile binfmt_misc bridge stp llc parport_pc ppdev arc4 iwlagn
snd_hda_codec_realtek iwlcore i915 snd_hda_intel mac80211 joydev
snd_hda_codec snd_hwdep snd_pcm snd_seq_midi drm_kms_helper
snd_rawmidi drm snd_seq_midi_event snd_seq snd_timer snd_seq_device
cfg80211 eeepc_wmi usbhid psmouse intel_agp i2c_algo_bit intel_gtt
uvcvideo agpgart videodev sparse_keymap snd shpchp v4l1_compat lp hid
video serio_raw soundcore output snd_page_alloc ahci libahci atl1c
Dec 15 14:36:41 User-PC kernel: [175576.122712]
Dec 15 14:36:41 User-PC kernel: [175576.122769] Pid: 0, comm:
kworker/0:0 Tainted: G W 2.6.37-rc5-wl+ #3 1015PE/1016P
Dec 15 14:36:41 User-PC kernel: [175576.123012] EIP: 0060:[<f83edd65>]
EFLAGS: 00010283 CPU: 1
Dec 15 14:36:41 User-PC kernel: [175576.123193] EIP is at
br_multicast_rcv+0xc95/0xe1c [bridge]
Dec 15 14:36:41 User-PC kernel: [175576.123362] EAX: 0000001c EBX:
f5626318 ECX: 00000000 EDX: 00000000
Dec 15 14:36:41 User-PC kernel: [175576.123550] ESI: ec512262 EDI:
f5626180 EBP: f60b5ca0 ESP: f60b5bd8
Dec 15 14:36:41 User-PC kernel: [175576.123737] DS: 007b ES: 007b FS:
00d8 GS: 00e0 SS: 0068
Dec 15 14:36:41 User-PC kernel: [175576.123902] Process kworker/0:0
(pid: 0, ti=f60b4000 task=f60a8000 task.ti=f60b0000)
Dec 15 14:36:41 User-PC kernel: [175576.124137] Stack:
Dec 15 14:36:41 User-PC kernel: [175576.124181] ec556500 f6d06800
f60b5be8 c01087d8 ec512262 00000030 00000024 f5626180
Dec 15 14:36:41 User-PC kernel: [175576.124181] f572c200 ef463440
f5626300 3affffff f6d06dd0 e60766a4 000000c4 f6d06860
Dec 15 14:36:41 User-PC kernel: [175576.124181] ffffffff ec55652c
00000001 f6d06844 f60b5c64 c0138264 c016e451 c013e47d
Dec 15 14:36:41 User-PC kernel: [175576.124181] Call Trace:
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c01087d8>] ?
sched_clock+0x8/0x10
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0138264>] ?
enqueue_entity+0x174/0x440
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c016e451>] ?
sched_clock_cpu+0x131/0x190
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c013e47d>] ?
select_task_rq_fair+0x2ad/0x730
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0524fc1>] ?
nf_iterate+0x71/0x90
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f83e4914>] ?
br_handle_frame_finish+0x184/0x220 [bridge]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f83e4790>] ?
br_handle_frame_finish+0x0/0x220 [bridge]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f83e46e9>] ?
br_handle_frame+0x189/0x230 [bridge]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f83e4790>] ?
br_handle_frame_finish+0x0/0x220 [bridge]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f83e4560>] ?
br_handle_frame+0x0/0x230 [bridge]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c04ff026>] ?
__netif_receive_skb+0x1b6/0x5b0
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c04f7a30>] ?
skb_copy_bits+0x110/0x210
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0503a7f>] ?
netif_receive_skb+0x6f/0x80
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f82cb74c>] ?
ieee80211_deliver_skb+0x8c/0x1a0 [mac80211]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f82cc836>] ?
ieee80211_rx_handlers+0xeb6/0x1aa0 [mac80211]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c04ff1f0>] ?
__netif_receive_skb+0x380/0x5b0
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c016e242>] ?
sched_clock_local+0xb2/0x190
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c012b688>] ?
default_spin_lock_flags+0x8/0x10
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c05d83df>] ?
_raw_spin_lock_irqsave+0x2f/0x50
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f82cd621>] ?
ieee80211_prepare_and_rx_handle+0x201/0xa90 [mac80211]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f82ce154>] ?
ieee80211_rx+0x2a4/0x830 [mac80211]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f815a8d6>] ?
iwl_update_stats+0xa6/0x2a0 [iwlcore]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f8499212>] ?
iwlagn_rx_reply_rx+0x292/0x3b0 [iwlagn]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c05d83df>] ?
_raw_spin_lock_irqsave+0x2f/0x50
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f8483697>] ?
iwl_rx_handle+0xe7/0x350 [iwlagn]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f8486ab7>] ?
iwl_irq_tasklet+0xf7/0x5c0 [iwlagn]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c01aece1>] ?
__rcu_process_callbacks+0x201/0x2d0
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0150d05>] ?
tasklet_action+0xc5/0x100
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0150a07>] ?
__do_softirq+0x97/0x1d0
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c05d910c>] ?
nmi_stack_correct+0x2f/0x34
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0150970>] ?
__do_softirq+0x0/0x1d0
Dec 15 14:36:41 User-PC kernel: [175576.124181] <IRQ>
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c01508f5>] ?
irq_exit+0x65/0x70
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c05df062>] ? do_IRQ+0x52/0xc0
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c01036b0>] ?
common_interrupt+0x30/0x38
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c03a1fc2>] ?
intel_idle+0xc2/0x160
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c04daebb>] ?
cpuidle_idle_call+0x6b/0x100
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0101dea>] ?
cpu_idle+0x8a/0xf0
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c05d2702>] ?
start_secondary+0x1e8/0x1ee
Dec 15 14:36:41 User-PC kernel: [175576.124181] Code: ff ff ff be ea
ff ff ff 8b 82 b0 00 00 00 e9 fb f5 ff ff 89 c8 e8 4c dc ff ff 85 c0
89 c6 0f 84 9b f5 ff ff 66 90 e9 be fe ff ff <0f> 0b eb fe c7 47 20 01
00 00 00 8b 43 04 89 c2 81 e2 ff ff ff
Dec 15 14:36:41 User-PC kernel: [175576.124181] EIP: [<f83edd65>]
br_multicast_rcv+0xc95/0xe1c [bridge] SS:ESP 0068:f60b5bd8
Dec 15 14:36:41 User-PC kernel: [175576.124181] BUG: scheduling while
atomic: kworker/0:0/0/0x10000100
Dec 15 14:36:41 User-PC kernel: [175576.124181] Modules linked in:
oprofile binfmt_misc bridge stp llc parport_pc ppdev arc4 iwlagn
snd_hda_codec_realtek iwlcore i915 snd_hda_intel mac80211 joydev
snd_hda_codec snd_hwdep snd_pcm snd_seq_midi drm_kms_helper
snd_rawmidi drm snd_seq_midi_event snd_seq snd_timer snd_seq_device
cfg80211 eeepc_wmi usbhid psmouse intel_agp i2c_algo_bit intel_gtt
uvcvideo agpgart videodev sparse_keymap snd shpchp v4l1_compat lp hid
video serio_raw soundcore output snd_page_alloc ahci libahci atl1c
Dec 15 14:36:41 User-PC kernel: [175576.124181] Modules linked in:
oprofile binfmt_misc bridge stp llc parport_pc ppdev arc4 iwlagn
snd_hda_codec_realtek iwlcore i915 snd_hda_intel mac80211 joydev
snd_hda_codec snd_hwdep snd_pcm snd_seq_midi drm_kms_helper
snd_rawmidi drm snd_seq_midi_event snd_seq snd_timer snd_seq_device
cfg80211 eeepc_wmi usbhid psmouse intel_agp i2c_algo_bit intel_gtt
uvcvideo agpgart videodev sparse_keymap snd shpchp v4l1_compat lp hid
video serio_raw soundcore output snd_page_alloc ahci libahci atl1c
Dec 15 14:36:41 User-PC kernel: [175576.124181]
Dec 15 14:36:41 User-PC kernel: [175576.124181] Pid: 0, comm:
kworker/0:0 Tainted: G W 2.6.37-rc5-wl+ #3 1015PE/1016P
Dec 15 14:36:41 User-PC kernel: [175576.124181] EIP: 0060:[<c03a1fc2>]
EFLAGS: 00000202 CPU: 1
Dec 15 14:36:41 User-PC kernel: [175576.124181] EIP is at intel_idle+0xc2/0x160
Dec 15 14:36:41 User-PC kernel: [175576.124181] EAX: 00000000 EBX:
00001494 ECX: 00000000 EDX: 00001494
Dec 15 14:36:41 User-PC kernel: [175576.124181] ESI: 00000000 EDI:
00000004 EBP: f60b1f50 ESP: f60b1f28
Dec 15 14:36:41 User-PC kernel: [175576.124181] DS: 007b ES: 007b FS:
00d8 GS: 00e0 SS: 0068
Dec 15 14:36:41 User-PC kernel: [175576.124181] Process kworker/0:0
(pid: 0, ti=f60b4000 task=f60a8000 task.ti=f60b0000)
Dec 15 14:36:41 User-PC kernel: [175576.124181] Stack:
Dec 15 14:36:41 User-PC kernel: [175576.124181] 0000000b 00000000
77359400 00000001 00000010 00000002 00000001 f6d0a95c
Dec 15 14:36:41 User-PC kernel: [175576.124181] f6d0aa1c c0817f04
f60b1f60 c04daebb 00000001 00000001 f60b1f84 c0101dea
Dec 15 14:36:41 User-PC kernel: [175576.124181] c07d0ef4 f60b1f7c
e487e262 f2eb6781 85a608d2 00000000 00000000 f60b1fb0
Dec 15 14:36:41 User-PC kernel: [175576.124181] Call Trace:
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c04daebb>] ?
cpuidle_idle_call+0x6b/0x100
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0101dea>] ?
cpu_idle+0x8a/0xf0
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c05d2702>] ?
start_secondary+0x1e8/0x1ee
Dec 15 14:36:41 User-PC kernel: [175576.124181] Code: f6 89 e0 25 00
e0 ff ff 8b 40 08 a8 08 75 08 b1 01 8b 45 e8 0f 01 c9 e8 cd fc dc ff
29 d8 19 f2 e8 04 d6 da ff 89 c6 89 d3 fb 90 <8d> 74 26 00 85 3d 78 41
7e c0 75 0d 8d 55 f0 b8 05 00 00 00 e8
Dec 15 14:36:41 User-PC kernel: [175576.124181] Call Trace:
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c04daebb>]
cpuidle_idle_call+0x6b/0x100
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0101dea>] cpu_idle+0x8a/0xf0
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c05d2702>]
start_secondary+0x1e8/0x1ee
Dec 15 14:36:41 User-PC kernel: [175576.487562] BUG: scheduling while
atomic: kworker/0:0/0/0x10000100
Dec 15 14:36:41 User-PC kernel: [175576.497058] Modules linked in:
oprofile binfmt_misc bridge stp llc parport_pc ppdev arc4 iwlagn
snd_hda_codec_realtek iwlcore i915 snd_hda_intel mac80211 joydev
snd_hda_codec snd_hwdep snd_pcm snd_seq_midi drm_kms_helper
snd_rawmidi drm snd_seq_midi_event snd_seq snd_timer snd_seq_device
cfg80211 eeepc_wmi usbhid psmouse intel_agp i2c_algo_bit intel_gtt
uvcvideo agpgart videodev sparse_keymap snd shpchp v4l1_compat lp hid
video serio_raw soundcore output snd_page_alloc ahci libahci atl1c
Dec 15 14:36:41 User-PC kernel: [175576.522221] Modules linked in:
oprofile binfmt_misc bridge stp llc parport_pc ppdev arc4 iwlagn
snd_hda_codec_realtek iwlcore i915 snd_hda_intel mac80211 joydev
snd_hda_codec snd_hwdep snd_pcm snd_seq_midi drm_kms_helper
snd_rawmidi drm snd_seq_midi_event snd_seq snd_timer snd_seq_device
cfg80211 eeepc_wmi usbhid psmouse intel_agp i2c_algo_bit intel_gtt
uvcvideo agpgart videodev sparse_keymap snd shpchp v4l1_compat lp hid
video serio_raw soundcore output snd_page_alloc ahci libahci atl1c
Dec 15 14:36:41 User-PC kernel: [175576.550740]
Dec 15 14:36:41 User-PC kernel: [175576.557947] Pid: 0, comm:
kworker/0:0 Tainted: G W 2.6.37-rc5-wl+ #3 1015PE/1016P
Dec 15 14:36:41 User-PC kernel: [175576.565201] EIP: 0060:[<c03a1fc2>]
EFLAGS: 00000202 CPU: 1
Dec 15 14:36:41 User-PC kernel: [175576.572280] EIP is at intel_idle+0xc2/0x160
Dec 15 14:36:41 User-PC kernel: [175576.579125] EAX: 00000000 EBX:
00001494 ECX: 00000000 EDX: 00001494
Dec 15 14:36:41 User-PC kernel: [175576.585850] ESI: 00000000 EDI:
00000004 EBP: f60b1f50 ESP: f60b1f28
Dec 15 14:36:41 User-PC kernel: [175576.592460] DS: 007b ES: 007b FS:
00d8 GS: 00e0 SS: 0068
Dec 15 14:36:41 User-PC kernel: [175576.599021] Process kworker/0:0
(pid: 0, ti=f60b4000 task=f60a8000 task.ti=f60b0000)
Dec 15 14:36:41 User-PC kernel: [175576.605632] Stack:
Dec 15 14:36:41 User-PC kernel: [175576.612158] 0000000b 00000000
77359400 00000001 00000010 00000002 00000001 f6d0a95c
Dec 15 14:36:41 User-PC kernel: [175576.618953] f6d0aa1c c0817f04
f60b1f60 c04daebb 00000001 00000001 f60b1f84 c0101dea
Dec 15 14:36:41 User-PC kernel: [175576.625818] c07d0ef4 f60b1f7c
e487e262 f2eb6781 85a608d2 00000000 00000000 f60b1fb0
Dec 15 14:36:41 User-PC kernel: [175576.632737] Call Trace:
Dec 15 14:36:41 User-PC kernel: [175576.639461] [<c04daebb>] ?
cpuidle_idle_call+0x6b/0x100
Dec 15 14:36:41 User-PC kernel: [175576.646168] [<c0101dea>] ?
cpu_idle+0x8a/0xf0
Dec 15 14:36:41 User-PC kernel: [175576.652826] [<c05d2702>] ?
start_secondary+0x1e8/0x1ee
Dec 15 14:36:41 User-PC kernel: [175576.659441] Code: f6 89 e0 25 00
e0 ff ff 8b 40 08 a8 08 75 08 b1 01 8b 45 e8 0f 01 c9 e8 cd fc dc ff
29 d8 19 f2 e8 04 d6 da ff 89 c6 89 d3 fb 90 <8d> 74 26 00 85 3d 78 41
7e c0 75 0d 8d 55 f0 b8 05 00 00 00 e8
Dec 15 14:36:41 User-PC kernel: [175576.673805] Call Trace:
Dec 15 14:36:41 User-PC kernel: [175576.680668] [<c04daebb>]
cpuidle_idle_call+0x6b/0x100
Dec 15 14:36:41 User-PC kernel: [175576.687612] [<c0101dea>] cpu_idle+0x8a/0xf0
Dec 15 14:36:41 User-PC kernel: [175576.694516] [<c05d2702>]
start_secondary+0x1e8/0x1ee
Dec 15 14:36:41 User-PC kernel: [175576.711906] BUG: scheduling while
atomic: kworker/0:0/0/0x10000100
Dec 15 14:36:41 User-PC kernel: [175576.716280] Modules linked in:
oprofile binfmt_misc bridge stp llc parport_pc ppdev arc4 iwlagn
snd_hda_codec_realtek iwlcore i915 snd_hda_intel mac80211 joydev
snd_hda_codec snd_hwdep snd_pcm snd_seq_midi drm_kms_helper
snd_rawmidi drm snd_seq_midi_event snd_seq snd_timer snd_seq_device
cfg80211 eeepc_wmi usbhid psmouse intel_agp i2c_algo_bit intel_gtt
uvcvideo agpgart videodev sparse_keymap snd shpchp v4l1_compat lp hid
video serio_raw soundcore output snd_page_alloc ahci libahci atl1c
Dec 15 14:36:41 User-PC kernel: [175576.734197] Modules linked in:
oprofile binfmt_misc bridge stp llc parport_pc ppdev arc4 iwlagn
snd_hda_codec_realtek iwlcore i915 snd_hda_intel mac80211 joydev
snd_hda_codec snd_hwdep snd_pcm snd_seq_midi drm_kms_helper
snd_rawmidi drm snd_seq_midi_event snd_seq snd_timer snd_seq_device
cfg80211 eeepc_wmi usbhid psmouse intel_agp i2c_algo_bit intel_gtt
uvcvideo agpgart videodev sparse_keymap snd shpchp v4l1_compat lp hid
video serio_raw soundcore output snd_page_alloc ahci libahci atl1c
Dec 15 14:36:41 User-PC kernel: [175576.753330]
Dec 15 14:36:41 User-PC kernel: [175576.757845] Pid: 0, comm:
kworker/0:0 Tainted: G W 2.6.37-rc5-wl+ #3 1015PE/1016P
Dec 15 14:36:41 User-PC kernel: [175576.762389] EIP: 0060:[<c03a1fc2>]
EFLAGS: 00000202 CPU: 1
Dec 15 14:36:41 User-PC kernel: [175576.766809] EIP is at intel_idle+0xc2/0x160
Dec 15 14:36:41 User-PC kernel: [175576.771119] EAX: 00000000 EBX:
00001494 ECX: 00000000 EDX: 00001494
Dec 15 14:36:41 User-PC kernel: [175576.775348] ESI: 00000000 EDI:
00000004 EBP: f60b1f50 ESP: f60b1f28
Dec 15 14:36:41 User-PC kernel: [175576.780037] DS: 007b ES: 007b FS:
00d8 GS: 00e0 SS: 0068
Dec 15 14:36:41 User-PC kernel: [175576.784159] Process kworker/0:0
(pid: 0, ti=f60b4000 task=f60a8000 task.ti=f60b0000)
Dec 15 14:36:41 User-PC kernel: [175576.788286] Stack:
Dec 15 14:36:41 User-PC kernel: [175576.792375] 0000000b 00000000
77359400 00000001 00000010 00000002 00000001 f6d0a95c
On Thu, 2010-12-16 at 14:11 +0200, Tomas Winkler wrote:
> Dec 15 14:36:41 User-PC kernel: [175576.120452] kernel BUG at include/linux/skbuff.h:1178!
> Dec 15 14:36:41 User-PC kernel: [175576.123193] EIP is at br_multicast_rcv+0xc95/0xe1c [bridge]
So as I said to Tomas in private before -- it kinda looks like something
here is not handling paged SKBs correctly? But I would imaging that
causing more issues, unless there was a bug here that made bridging
require more data in the skb header than we put in there right now -- it
can end up being empty I believe.
Thing is, I looked at the code and it seemed fine.
johannes
On Thu, Dec 16, 2010 at 2:16 PM, Johannes Berg
<[email protected]> wrote:
> On Thu, 2010-12-16 at 14:11 +0200, Tomas Winkler wrote:
>
>> Dec 15 14:36:41 User-PC kernel: [175576.120452] kernel BUG at include/linux/skbuff.h:1178!
>
>> Dec 15 14:36:41 User-PC kernel: [175576.123193] EIP is at br_multicast_rcv+0xc95/0xe1c [bridge]
>
> So as I said to Tomas in private before -- it kinda looks like something
> here is not handling paged SKBs correctly? But I would imaging that
> causing more issues, unless there was a bug here that made bridging
> require more data in the skb header than we put in there right now -- it
> can end up being empty I believe.
>
> Thing is, I looked at the code and it seemed fine.
>
> johannes
>
opened bug https://bugzilla.kernel.org/show_bug.cgi?id=25202
>
On Thu, 2010-12-30 at 10:46 -0800, Stephen Hemminger wrote:
> This doesn't look correct. The calculation of the offset doesn't look correct.
> Just following the skb_clone(), the skb_pull value is "offset".
> Also, the other checks return -EINVAL for incorrectly formed packet.
>
> --- a/net/bridge/br_multicast.c 2010-12-30 10:29:58.579510488 -0800
> +++ b/net/bridge/br_multicast.c 2010-12-30 10:43:27.273386691 -0800
> @@ -1464,6 +1464,9 @@ static int br_multicast_ipv6_rcv(struct
> if (offset < 0 || nexthdr != IPPROTO_ICMPV6)
> return 0;
>
> + if (!pskb_may_pull(skb, offset))
> + return -EINVAL;
> +
> /* Okay, we found ICMPv6 header */
> skb2 = skb_clone(skb, GFP_ATOMIC);
> if (!skb2)
Wouldn't that make more sense after the clone anyway? But if you look at
my email, you'll find that there's potentially, and conditionally, more
stuff that will be read from the skb's header, which hasn't necessarily
been pulled in, so I think this still won't fix all the issues.
Seeing how this only affects some ICMPv6 packets, maybe we should just
use skb_copy() instead?
johannes
On Thu, 2010-12-16 at 14:11 +0200, Tomas Winkler wrote:
> Will be happy if someone can give me some more insight. (kernel 2.6.37-rc5)
Tomas looked into it a bit more and told me that it happens on IPv6
packets. To recap, he gets
kernel BUG at include/linux/skbuff.h:1178!
with
EIP: [<f83edd65>] br_multicast_rcv+0xc95/0xe1c [bridge]
Also remember that the packets are almost fully nonlinear, when they get
here they likely have almost no data in the skb header.
I then looked at br_multicast_ipv6_rcv(), and it looks fishy:
Up to:
skb2 = skb_clone(skb, GFP_ATOMIC);
everything's fine, since ipv6_skip_exthdr() will use
skb_header_pointer(). At this point, offset is the result of
ipv6_skip_exthdr(). Remember that skb_clone() is not skb_copy().
Then, however, we do
__skb_pull(skb2, offset);
At this point, however, I don't see anything that guarantees that all
"offset" bytes are part of the headroom -- and indeed I think this is
where it crashes.
If it didn't crash, because this many bytes were part of the header,
continuing further into the function, however, we could still crash:
if (!pskb_may_pull(skb2, sizeof(*icmp6h)))
goto out;
now makes sure that we can read the ICMPv6 header. Later, however, we do
case ICMPV6_MGM_REPORT:
{
struct mld_msg *mld = (struct mld_msg *)icmp6h;
BR_INPUT_SKB_CB(skb2)->mrouters_only = 1;
err = br_ip6_multicast_add_group(br, port, &mld->mld_mca);
which seems just as unsafe since "mld_mca" need not be part of the
header of the SKB. Similarly in another branch of this.
Additionally, I'm not convinced that there even is guaranteed to be
enough space in the SKB at all for the entire "struct mld_msg".
And finally, the error path in this function is confusing. Below patch
should be fine since unlike IPv4 (where this was copied maybe?) this
code unconditionally clones the SKB.
johannes
---
net/bridge/br_multicast.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
--- wireless-testing.orig/net/bridge/br_multicast.c 2010-12-29 15:45:03.000000000 +0100
+++ wireless-testing/net/bridge/br_multicast.c 2010-12-29 16:03:03.000000000 +0100
@@ -1430,7 +1430,7 @@ static int br_multicast_ipv6_rcv(struct
struct net_bridge_port *port,
struct sk_buff *skb)
{
- struct sk_buff *skb2 = skb;
+ struct sk_buff *skb2;
struct ipv6hdr *ip6h;
struct icmp6hdr *icmp6h;
u8 nexthdr;
@@ -1535,9 +1535,7 @@ static int br_multicast_ipv6_rcv(struct
}
out:
- __skb_push(skb2, offset);
- if (skb2 != skb)
- kfree_skb(skb2);
+ kfree_skb(skb2);
return err;
}
#endif
On Thu, 30 Dec 2010 19:52:14 +0100
Johannes Berg <[email protected]> wrote:
> On Thu, 2010-12-30 at 10:46 -0800, Stephen Hemminger wrote:
>
> > This doesn't look correct. The calculation of the offset doesn't look correct.
> > Just following the skb_clone(), the skb_pull value is "offset".
> > Also, the other checks return -EINVAL for incorrectly formed packet.
> >
> > --- a/net/bridge/br_multicast.c 2010-12-30 10:29:58.579510488 -0800
> > +++ b/net/bridge/br_multicast.c 2010-12-30 10:43:27.273386691 -0800
> > @@ -1464,6 +1464,9 @@ static int br_multicast_ipv6_rcv(struct
> > if (offset < 0 || nexthdr != IPPROTO_ICMPV6)
> > return 0;
> >
> > + if (!pskb_may_pull(skb, offset))
> > + return -EINVAL;
> > +
> > /* Okay, we found ICMPv6 header */
> > skb2 = skb_clone(skb, GFP_ATOMIC);
> > if (!skb2)
>
> Wouldn't that make more sense after the clone anyway? But if you look at
> my email, you'll find that there's potentially, and conditionally, more
> stuff that will be read from the skb's header, which hasn't necessarily
> been pulled in, so I think this still won't fix all the issues.
>
> Seeing how this only affects some ICMPv6 packets, maybe we should just
> use skb_copy() instead?
It comes out cleaner, and the check can be simplified.
--- a/net/bridge/br_multicast.c 2010-12-30 10:47:12.031733855 -0800
+++ b/net/bridge/br_multicast.c 2010-12-30 11:00:12.135801266 -0800
@@ -1465,19 +1465,19 @@ static int br_multicast_ipv6_rcv(struct
return 0;
/* Okay, we found ICMPv6 header */
- skb2 = skb_clone(skb, GFP_ATOMIC);
+ skb2 = skb_copy(skb, GFP_ATOMIC);
if (!skb2)
return -ENOMEM;
+ err = -EINVAL;
+ if (skb2->len < offset + sizeof(*icmp6h))
+ goto out;
+
len -= offset - skb_network_offset(skb2);
__skb_pull(skb2, offset);
skb_reset_transport_header(skb2);
- err = -EINVAL;
- if (!pskb_may_pull(skb2, sizeof(*icmp6h)))
- goto out;
-
icmp6h = icmp6_hdr(skb2);
switch (icmp6h->icmp6_type) {
--
use pskb_may_pull to access header correctly for paged skbs
the pskb_may_pull ideom is used ipv6 heder parsing
but omitted int the bridge code
this fixes bug https://bugzilla.kernel.org/show_bug.cgi?id=25202
Dec 15 14:36:40 User-PC hostapd: wlan0: STA 00:15:00:60:5d:34 IEEE 802.11: authenticated
Dec 15 14:36:40 User-PC hostapd: wlan0: STA 00:15:00:60:5d:34 IEEE 802.11: associated (aid 2)
Dec 15 14:36:40 User-PC hostapd: wlan0: STA 00:15:00:60:5d:34 RADIUS: starting accounting session 4D0608A3-00000005
Dec 15 14:36:41 User-PC kernel: [175576.120287] ------------[ cut here ]------------
Dec 15 14:36:41 User-PC kernel: [175576.120452] kernel BUG at include/linux/skbuff.h:1178!
Dec 15 14:36:41 User-PC kernel: [175576.120609] invalid opcode: 0000 [#1] SMP
Dec 15 14:36:41 User-PC kernel: [175576.120749] last sysfs file: /sys/devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0/block/sda/uevent
Dec 15 14:36:41 User-PC kernel: [175576.121035] Modules linked in: oprofile binfmt_misc bridge stp llc parport_pc ppdev arc4 iwlagn snd_hda_codec_realtek iwlcore i915 snd_hda_intel mac80211 joydev snd_hda_codec snd_hwdep snd_pcm snd_seq_midi drm_kms_helper snd_rawmidi drm snd_seq_midi_event snd_seq snd_timer snd_seq_device cfg80211 eeepc_wmi usbhid psmouse intel_agp i2c_algo_bit intel_gtt uvcvideo agpgart videodev sparse_keymap snd shpchp v4l1_compat lp hid video serio_raw soundcore output snd_page_alloc ahci libahci atl1c
Dec 15 14:36:41 User-PC kernel: [175576.122712]
Dec 15 14:36:41 User-PC kernel: [175576.122769] Pid: 0, comm: kworker/0:0 Tainted: G W 2.6.37-rc5-wl+ #3 1015PE/1016P
Dec 15 14:36:41 User-PC kernel: [175576.123012] EIP: 0060:[<f83edd65>] EFLAGS: 00010283 CPU: 1
Dec 15 14:36:41 User-PC kernel: [175576.123193] EIP is at br_multicast_rcv+0xc95/0xe1c [bridge]
Dec 15 14:36:41 User-PC kernel: [175576.123362] EAX: 0000001c EBX: f5626318 ECX: 00000000 EDX: 00000000
Dec 15 14:36:41 User-PC kernel: [175576.123550] ESI: ec512262 EDI: f5626180 EBP: f60b5ca0 ESP: f60b5bd8
Dec 15 14:36:41 User-PC kernel: [175576.123737] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
Dec 15 14:36:41 User-PC kernel: [175576.123902] Process kworker/0:0 (pid: 0, ti=f60b4000 task=f60a8000 task.ti=f60b0000)
Dec 15 14:36:41 User-PC kernel: [175576.124137] Stack:
Dec 15 14:36:41 User-PC kernel: [175576.124181] ec556500 f6d06800 f60b5be8 c01087d8 ec512262 00000030 00000024 f5626180
Dec 15 14:36:41 User-PC kernel: [175576.124181] f572c200 ef463440 f5626300 3affffff f6d06dd0 e60766a4 000000c4 f6d06860
Dec 15 14:36:41 User-PC kernel: [175576.124181] ffffffff ec55652c 00000001 f6d06844 f60b5c64 c0138264 c016e451 c013e47d
Dec 15 14:36:41 User-PC kernel: [175576.124181] Call Trace:
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c01087d8>] ? sched_clock+0x8/0x10
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0138264>] ? enqueue_entity+0x174/0x440
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c016e451>] ? sched_clock_cpu+0x131/0x190
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c013e47d>] ? select_task_rq_fair+0x2ad/0x730
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0524fc1>] ? nf_iterate+0x71/0x90
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f83e4914>] ? br_handle_frame_finish+0x184/0x220 [bridge]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f83e4790>] ? br_handle_frame_finish+0x0/0x220 [bridge]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f83e46e9>] ? br_handle_frame+0x189/0x230 [bridge]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f83e4790>] ? br_handle_frame_finish+0x0/0x220 [bridge]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f83e4560>] ? br_handle_frame+0x0/0x230 [bridge]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c04ff026>] ? __netif_receive_skb+0x1b6/0x5b0
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c04f7a30>] ? skb_copy_bits+0x110/0x210
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0503a7f>] ? netif_receive_skb+0x6f/0x80
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f82cb74c>] ? ieee80211_deliver_skb+0x8c/0x1a0 [mac80211]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f82cc836>] ? ieee80211_rx_handlers+0xeb6/0x1aa0 [mac80211]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c04ff1f0>] ? __netif_receive_skb+0x380/0x5b0
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c016e242>] ? sched_clock_local+0xb2/0x190
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c012b688>] ? default_spin_lock_flags+0x8/0x10
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c05d83df>] ? _raw_spin_lock_irqsave+0x2f/0x50
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f82cd621>] ? ieee80211_prepare_and_rx_handle+0x201/0xa90 [mac80211]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f82ce154>] ? ieee80211_rx+0x2a4/0x830 [mac80211]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f815a8d6>] ? iwl_update_stats+0xa6/0x2a0 [iwlcore]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f8499212>] ? iwlagn_rx_reply_rx+0x292/0x3b0 [iwlagn]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c05d83df>] ? _raw_spin_lock_irqsave+0x2f/0x50
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f8483697>] ? iwl_rx_handle+0xe7/0x350 [iwlagn]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f8486ab7>] ? iwl_irq_tasklet+0xf7/0x5c0 [iwlagn]
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c01aece1>] ? __rcu_process_callbacks+0x201/0x2d0
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0150d05>] ? tasklet_action+0xc5/0x100
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0150a07>] ? __do_softirq+0x97/0x1d0
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c05d910c>] ? nmi_stack_correct+0x2f/0x34
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0150970>] ? __do_softirq+0x0/0x1d0
Dec 15 14:36:41 User-PC kernel: [175576.124181] <IRQ>
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c01508f5>] ? irq_exit+0x65/0x70
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c05df062>] ? do_IRQ+0x52/0xc0
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c01036b0>] ? common_interrupt+0x30/0x38
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c03a1fc2>] ? intel_idle+0xc2/0x160
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c04daebb>] ? cpuidle_idle_call+0x6b/0x100
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0101dea>] ? cpu_idle+0x8a/0xf0
Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c05d2702>] ? start_secondary+0x1e8/0x1ee
Cc:YOSHIFUJI Hideaki <[email protected]>
Cc: Johannes Berg <[email protected]>
Signed-off-by: Tomas Winkler <[email protected]>
---
net/bridge/br_multicast.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index f19e347..074c478 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1464,6 +1464,10 @@ static int br_multicast_ipv6_rcv(struct net_bridge *br,
if (offset < 0 || nexthdr != IPPROTO_ICMPV6)
return 0;
+ if (!pskb_may_pull(skb,
+ (skb_network_header(skb) + offset + 1 - skb->data)))
+ return 0;
+
/* Okay, we found ICMPv6 header */
skb2 = skb_clone(skb, GFP_ATOMIC);
if (!skb2)
--
1.7.3.4
---------------------------------------------------------------------
Intel Israel (74) Limited
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On Thu, 30 Dec 2010 13:32:33 +0200
Tomas Winkler <[email protected]> wrote:
> use pskb_may_pull to access header correctly for paged skbs
>
> the pskb_may_pull ideom is used ipv6 heder parsing
> but omitted int the bridge code
>
> this fixes bug https://bugzilla.kernel.org/show_bug.cgi?id=25202
>
> Dec 15 14:36:40 User-PC hostapd: wlan0: STA 00:15:00:60:5d:34 IEEE 802.11: authenticated
> Dec 15 14:36:40 User-PC hostapd: wlan0: STA 00:15:00:60:5d:34 IEEE 802.11: associated (aid 2)
> Dec 15 14:36:40 User-PC hostapd: wlan0: STA 00:15:00:60:5d:34 RADIUS: starting accounting session 4D0608A3-00000005
> Dec 15 14:36:41 User-PC kernel: [175576.120287] ------------[ cut here ]------------
> Dec 15 14:36:41 User-PC kernel: [175576.120452] kernel BUG at include/linux/skbuff.h:1178!
> Dec 15 14:36:41 User-PC kernel: [175576.120609] invalid opcode: 0000 [#1] SMP
> Dec 15 14:36:41 User-PC kernel: [175576.120749] last sysfs file: /sys/devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0/block/sda/uevent
> Dec 15 14:36:41 User-PC kernel: [175576.121035] Modules linked in: oprofile binfmt_misc bridge stp llc parport_pc ppdev arc4 iwlagn snd_hda_codec_realtek iwlcore i915 snd_hda_intel mac80211 joydev snd_hda_codec snd_hwdep snd_pcm snd_seq_midi drm_kms_helper snd_rawmidi drm snd_seq_midi_event snd_seq snd_timer snd_seq_device cfg80211 eeepc_wmi usbhid psmouse intel_agp i2c_algo_bit intel_gtt uvcvideo agpgart videodev sparse_keymap snd shpchp v4l1_compat lp hid video serio_raw soundcore output snd_page_alloc ahci libahci atl1c
> Dec 15 14:36:41 User-PC kernel: [175576.122712]
> Dec 15 14:36:41 User-PC kernel: [175576.122769] Pid: 0, comm: kworker/0:0 Tainted: G W 2.6.37-rc5-wl+ #3 1015PE/1016P
> Dec 15 14:36:41 User-PC kernel: [175576.123012] EIP: 0060:[<f83edd65>] EFLAGS: 00010283 CPU: 1
> Dec 15 14:36:41 User-PC kernel: [175576.123193] EIP is at br_multicast_rcv+0xc95/0xe1c [bridge]
> Dec 15 14:36:41 User-PC kernel: [175576.123362] EAX: 0000001c EBX: f5626318 ECX: 00000000 EDX: 00000000
> Dec 15 14:36:41 User-PC kernel: [175576.123550] ESI: ec512262 EDI: f5626180 EBP: f60b5ca0 ESP: f60b5bd8
> Dec 15 14:36:41 User-PC kernel: [175576.123737] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
> Dec 15 14:36:41 User-PC kernel: [175576.123902] Process kworker/0:0 (pid: 0, ti=f60b4000 task=f60a8000 task.ti=f60b0000)
> Dec 15 14:36:41 User-PC kernel: [175576.124137] Stack:
> Dec 15 14:36:41 User-PC kernel: [175576.124181] ec556500 f6d06800 f60b5be8 c01087d8 ec512262 00000030 00000024 f5626180
> Dec 15 14:36:41 User-PC kernel: [175576.124181] f572c200 ef463440 f5626300 3affffff f6d06dd0 e60766a4 000000c4 f6d06860
> Dec 15 14:36:41 User-PC kernel: [175576.124181] ffffffff ec55652c 00000001 f6d06844 f60b5c64 c0138264 c016e451 c013e47d
> Dec 15 14:36:41 User-PC kernel: [175576.124181] Call Trace:
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c01087d8>] ? sched_clock+0x8/0x10
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0138264>] ? enqueue_entity+0x174/0x440
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c016e451>] ? sched_clock_cpu+0x131/0x190
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c013e47d>] ? select_task_rq_fair+0x2ad/0x730
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0524fc1>] ? nf_iterate+0x71/0x90
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f83e4914>] ? br_handle_frame_finish+0x184/0x220 [bridge]
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f83e4790>] ? br_handle_frame_finish+0x0/0x220 [bridge]
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f83e46e9>] ? br_handle_frame+0x189/0x230 [bridge]
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f83e4790>] ? br_handle_frame_finish+0x0/0x220 [bridge]
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f83e4560>] ? br_handle_frame+0x0/0x230 [bridge]
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c04ff026>] ? __netif_receive_skb+0x1b6/0x5b0
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c04f7a30>] ? skb_copy_bits+0x110/0x210
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0503a7f>] ? netif_receive_skb+0x6f/0x80
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f82cb74c>] ? ieee80211_deliver_skb+0x8c/0x1a0 [mac80211]
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f82cc836>] ? ieee80211_rx_handlers+0xeb6/0x1aa0 [mac80211]
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c04ff1f0>] ? __netif_receive_skb+0x380/0x5b0
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c016e242>] ? sched_clock_local+0xb2/0x190
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c012b688>] ? default_spin_lock_flags+0x8/0x10
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c05d83df>] ? _raw_spin_lock_irqsave+0x2f/0x50
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f82cd621>] ? ieee80211_prepare_and_rx_handle+0x201/0xa90 [mac80211]
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f82ce154>] ? ieee80211_rx+0x2a4/0x830 [mac80211]
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f815a8d6>] ? iwl_update_stats+0xa6/0x2a0 [iwlcore]
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f8499212>] ? iwlagn_rx_reply_rx+0x292/0x3b0 [iwlagn]
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c05d83df>] ? _raw_spin_lock_irqsave+0x2f/0x50
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f8483697>] ? iwl_rx_handle+0xe7/0x350 [iwlagn]
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<f8486ab7>] ? iwl_irq_tasklet+0xf7/0x5c0 [iwlagn]
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c01aece1>] ? __rcu_process_callbacks+0x201/0x2d0
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0150d05>] ? tasklet_action+0xc5/0x100
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0150a07>] ? __do_softirq+0x97/0x1d0
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c05d910c>] ? nmi_stack_correct+0x2f/0x34
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0150970>] ? __do_softirq+0x0/0x1d0
> Dec 15 14:36:41 User-PC kernel: [175576.124181] <IRQ>
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c01508f5>] ? irq_exit+0x65/0x70
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c05df062>] ? do_IRQ+0x52/0xc0
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c01036b0>] ? common_interrupt+0x30/0x38
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c03a1fc2>] ? intel_idle+0xc2/0x160
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c04daebb>] ? cpuidle_idle_call+0x6b/0x100
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c0101dea>] ? cpu_idle+0x8a/0xf0
> Dec 15 14:36:41 User-PC kernel: [175576.124181] [<c05d2702>] ? start_secondary+0x1e8/0x1ee
>
> Cc:YOSHIFUJI Hideaki <[email protected]>
> Cc: Johannes Berg <[email protected]>
> Signed-off-by: Tomas Winkler <[email protected]>
> ---
> net/bridge/br_multicast.c | 4 ++++
> 1 files changed, 4 insertions(+), 0 deletions(-)
>
> diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
> index f19e347..074c478 100644
> --- a/net/bridge/br_multicast.c
> +++ b/net/bridge/br_multicast.c
> @@ -1464,6 +1464,10 @@ static int br_multicast_ipv6_rcv(struct net_bridge *br,
> if (offset < 0 || nexthdr != IPPROTO_ICMPV6)
> return 0;
>
> + if (!pskb_may_pull(skb,
> + (skb_network_header(skb) + offset + 1 - skb->data)))
> + return 0;
> +
> /* Okay, we found ICMPv6 header */
> skb2 = skb_clone(skb, GFP_ATOMIC);
> if (!skb2)
This doesn't look correct. The calculation of the offset doesn't look correct.
Just following the skb_clone(), the skb_pull value is "offset".
Also, the other checks return -EINVAL for incorrectly formed packet.
--- a/net/bridge/br_multicast.c 2010-12-30 10:29:58.579510488 -0800
+++ b/net/bridge/br_multicast.c 2010-12-30 10:43:27.273386691 -0800
@@ -1464,6 +1464,9 @@ static int br_multicast_ipv6_rcv(struct
if (offset < 0 || nexthdr != IPPROTO_ICMPV6)
return 0;
+ if (!pskb_may_pull(skb, offset))
+ return -EINVAL;
+
/* Okay, we found ICMPv6 header */
skb2 = skb_clone(skb, GFP_ATOMIC);
if (!skb2)
--
> -----Original Message-----
> From: Stephen Hemminger [mailto:[email protected]]
> Sent: Thursday, December 30, 2010 9:06 PM
> To: Johannes Berg
> Cc: Winkler, Tomas; [email protected]; [email protected]; linux-
> [email protected]
> Subject: Re: [PATCH net-2.6] bridge: fix br_multicast_ipv6_rcv for paged
> skbs
>
> On Thu, 30 Dec 2010 19:52:14 +0100
> Johannes Berg <[email protected]> wrote:
>
> > On Thu, 2010-12-30 at 10:46 -0800, Stephen Hemminger wrote:
> >
> > > This doesn't look correct. The calculation of the offset doesn't look
> correct.
> > > Just following the skb_clone(), the skb_pull value is "offset".
> > > Also, the other checks return -EINVAL for incorrectly formed packet.
> > >
> > > --- a/net/bridge/br_multicast.c 2010-12-30 10:29:58.579510488 -0800
> > > +++ b/net/bridge/br_multicast.c 2010-12-30 10:43:27.273386691 -0800
> > > @@ -1464,6 +1464,9 @@ static int br_multicast_ipv6_rcv(struct
> > > if (offset < 0 || nexthdr != IPPROTO_ICMPV6)
> > > return 0;
> > >
> > > + if (!pskb_may_pull(skb, offset))
> > > + return -EINVAL;
> > > +
> > > /* Okay, we found ICMPv6 header */
> > > skb2 = skb_clone(skb, GFP_ATOMIC);
> > > if (!skb2)
> >
> > Wouldn't that make more sense after the clone anyway? But if you look at
> > my email, you'll find that there's potentially, and conditionally, more
> > stuff that will be read from the skb's header, which hasn't necessarily
> > been pulled in, so I think this still won't fix all the issues.
> >
> > Seeing how this only affects some ICMPv6 packets, maybe we should just
> > use skb_copy() instead?
>
> It comes out cleaner, and the check can be simplified.
>
> --- a/net/bridge/br_multicast.c 2010-12-30 10:47:12.031733855 -0800
> +++ b/net/bridge/br_multicast.c 2010-12-30 11:00:12.135801266 -0800
> @@ -1465,19 +1465,19 @@ static int br_multicast_ipv6_rcv(struct
> return 0;
>
> /* Okay, we found ICMPv6 header */
> - skb2 = skb_clone(skb, GFP_ATOMIC);
> + skb2 = skb_copy(skb, GFP_ATOMIC);
> if (!skb2)
> return -ENOMEM;
>
> + err = -EINVAL;
> + if (skb2->len < offset + sizeof(*icmp6h))
> + goto out;
> +
> len -= offset - skb_network_offset(skb2);
>
> __skb_pull(skb2, offset);
> skb_reset_transport_header(skb2);
>
> - err = -EINVAL;
> - if (!pskb_may_pull(skb2, sizeof(*icmp6h)))
> - goto out;
> -
> icmp6h = icmp6_hdr(skb2);
>
> switch (icmp6h->icmp6_type) {
>
>
Sorry for dump question but isn't there performance penalty on using skb_copy vs. skb_clone?
Anyhow Below is a code snippet from ip6_input.c so you probably would want to fix it all over.
BTW offset and the pointer arithmetic really gives the same number +1, I'm not surly why the original author would thought it be safer than just using offset.
offset = ipv6_skip_exthdr(skb, sizeof(*hdr),
&nexthdr);
if (offset < 0)
goto out;
if (nexthdr != IPPROTO_ICMPV6)
goto out;
if (!pskb_may_pull(skb, (skb_network_header(skb) +
offset + 1 - skb->data)))
goto out;
icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
Thanks
Tomas
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2010/12/29 Johannes Berg <[email protected]>:
> On Thu, 2010-12-16 at 14:11 +0200, Tomas Winkler wrote:
>> Will be happy if someone can give me some more insight. (kernel 2.6.37-rc5)
>
> Tomas looked into it a bit more and told me that it happens on IPv6
> packets. To recap, he gets
>
> kernel BUG at include/linux/skbuff.h:1178!
> with
> EIP: [<f83edd65>] br_multicast_rcv+0xc95/0xe1c [bridge]
>
> Also remember that the packets are almost fully nonlinear, when they get
> here they likely have almost no data in the skb header.
>
> I then looked at br_multicast_ipv6_rcv(), and it looks fishy:
>
> Up to:
> skb2 = skb_clone(skb, GFP_ATOMIC);
>
> everything's fine, since ipv6_skip_exthdr() will use
> skb_header_pointer(). At this point, offset is the result of
> ipv6_skip_exthdr(). Remember that skb_clone() is not skb_copy().
So far I can confirm that switching to sbk_copy fixes the crash.
Thanks
Tomas