On 12/16/2016 07:46 AM, Wong, Joshua Weng Onn wrote: > Hi, > > I have enabled 6lowpan and bluetooth 6lowpan in the kernel configuration on two systems. Both these systems are running linux and one act as a master and another act as a slave. > I am facing a bug while in a bluetooth 6lowpan connection. This happens during a ping6. The kernel version that I am using is 4.1.27 with BlueZ 5.40 on a x86_64 architecture. The kernel reports regarding slab corruption. > > The steps that I have performed are as follows: > Slave device: > $ modprobe 6lowpan > $ modprobe Bluetooth_6lowpan > $ echo 1 > /sys/kernel/debug/bluetooth/6lowpan_enable > $ hciconfig hci0 leadv > > Master device: > $ modprobe 6lowpan > $ modprobe bluetooth_6lowpan > $ echo 1 > /sys/kernel/debug/bluetooth/6lowpan_enable > $ hcitool lescan << to obtain slave BT ADDR $ echo "connect > <remote_BT_MAC> 1" > /sys/kernel/debug/bluetooth/6lowpan_control > $ ifconfig (look for bt0 interface) << to obtain IPv6 address of slave device > $ ping6 -I bt0 <IPV6_ADDR> <<<<------ The console message starts to appear here during ping6 > > The output of the console message: > > [ 794.985623] Slab corruption (Tainted: G U ): skbuff_head_cache start=ffff8801f568f700, len=232 > [ 795.008755] 050: 00 00 00 00 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b > ....kkkkkkkkkkkk [ 795.029380] Prev obj: start=ffff8801f568f600, > len=232 [ 795.044743] 000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > [ 795.061310] 010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > [ 795.076752] Next obj: start=ffff8801f568f800, len=232 [ > 795.088448] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b > kkkkkkkkkkkkkkkk [ 795.102365] 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b > 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk > > The 6lowpan connection between the two devices is connected. > I observed that the console message appears once when the master initiates the connection to the slave and nothing happens after that. > Once I start doing the ping6 from master to slave, the same message appears again. This same set of message continues to be printed every 5 seconds or so. > This also persists when ping6 is done from the slave to the master. > > Do you know what could possibly cause this issue? > > Please let me know if you require further information. > In short: BTLE 6LoWPAN is broken. Patch-Series which needs some love to fix some issues (mostly races/L2 address handling with L3 stuff, use ndisc stuff, still exists open question which L2 address should be used) exists at [0]. Maybe YOU want to bring it mainline -> I have no time currently to do that. Of maybe you can test it and tell me your expierence. :-) If you want still to use the current code, I recommend to disable SMP... but races still exists. Also update the kernel version to a recent one. - Alex [0] http://www.spinics.net/lists/linux-wpan/msg04124.html Thank you for informing me about this. Sorry as I was not aware of the newer patches that you submitted to mainline. At the moment I am not able to upgrade the kernel to a recent version as the other teams in my department are using kernel version 4.1.27 and I have to follow it strictly. I just got an idea. Perhaps what I can do is backport the patches and apply them to this version of the kernel. I am not sure if it will work entirely. I'll discuss this with my lead first if he wants me to do this and let you know if I am pursuing this. Best regards, Joshua -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-wpan" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
