On 08/30/2017 11:50 PM, Zvi Effron wrote:
I managed to set up my configuration with a VM on VMware Workstation, and it did not reproduce the bug. I think it was using one of the Intel drivers, though, instead of the generic. Is there a way to force the use of the generic driver?
I actually doubt that the trace printk issue you've seen has anything to do with XDP native/generic side, but verifying it would be good nevertheless. For more recent iproute2, you can enforce either side (internally using the XDP_FLAGS_DRV_MODE and XDP_FLAGS_SKB_MODE flags Dave just mentioned): * Enforce native mode: ip link set dev foo xdpdrv obj ./xdp_test_kern.o sec .text * Enforce generic mode: ip link set dev foo xdpgeneric obj ./xdp_test_kern.o sec .text Did anything else change in your setup, like kernel config, etc, that could play a role here? Thanks, Daniel
On Wed, Aug 30, 2017 at 2:25 PM, Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote:On 08/30/2017 07:53 PM, Zvi Effron wrote:I've uploaded the object file to https://drive.google.com/file/d/0B-lMs4mJOgQBU090ZzNtSkVnMTQ/view?usp=sharing uname -a output: Linux localhost.localdomain 4.12.8-300.fc26.x86_64 #1 SMP Thu Aug 17 15:30:20 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux ip -V output: ip utility, iproute2-ss170501 I tried with latest iproute2 built from source (ip -V output: ip utility, iproute2-ss170705) and am still having the same issue. (I also first noticed this with a custom loader I wrote, so I think the loader can probably be ruled out.) sysctl -a 2> /dev/null | grep bpf output: kernel.unprivileged_bpf_disabled = 0 net.core.bpf_jit_enable = 0 net.core.bpf_jit_harden = 0 net.core.bpf_jit_kallsyms = 0 Thanks for helping look into this! Let me know if you need any more info.Here are my results with your object file; seems to work fine for me there, good but still strange. ;) I took the actual 4.12.8 stable kernel. # uname -a Linux linux-2.home 4.12.8 #1 SMP Wed Aug 30 21:27:51 CEST 2017 x86_64 x86_64 x86_64 GNU/Linux # ip -V ip utility, iproute2-ss170705 # sysctl -a | grep bpf kernel.unprivileged_bpf_disabled = 0 net.core.bpf_jit_enable = 0 net.core.bpf_jit_harden = 0 net.core.bpf_jit_kallsyms = 0 # ip link set dev wlp4s0 xdpgeneric obj ./xdp_test_kern.o sec .text # tc exec bpf dbg # cmd is just finding mount and dumping trace pipe Running! Hang up with ^C! irq/131-iwlwifi-710 [003] .... 892.116200: : Data start: 90941a Data end: 909456 irq/131-iwlwifi-710 [003] .... 892.116216: : Constant: 1 irq/131-iwlwifi-710 [003] .... 893.346855: : Data start: 90801a Data end: 908044 irq/131-iwlwifi-710 [003] .... 893.346871: : Constant: 1 irq/131-iwlwifi-710 [003] .... 893.346917: : Data start: 90801a Data end: 908070 irq/131-iwlwifi-710 [003] .... 893.346921: : Constant: 1 irq/131-iwlwifi-710 [003] .... 893.654076: : Data start: 90801a Data end: 908044 irq/131-iwlwifi-710 [003] .... 893.654092: : Constant: 1 irq/131-iwlwifi-710 [003] .... 901.333823: : Data start: 88dfc1a Data end: 88dfcb8 irq/131-iwlwifi-710 [003] .... 901.333839: : Constant: 1 irq/131-iwlwifi-710 [003] .... 907.578693: : Data start: 90801a Data end: 90804c irq/131-iwlwifi-710 [003] .... 907.578722: : Constant: 1 irq/131-iwlwifi-710 [003] .... 908.192621: : Data start: 90801a Data end: 908044 irq/131-iwlwifi-710 [003] .... 908.192634: : Constant: 1 irq/131-iwlwifi-710 [003] .... 908.192696: : Data start: 90801a Data end: 908070 irq/131-iwlwifi-710 [003] .... 908.192701: : Constant: 1 irq/131-iwlwifi-710 [003] .... 908.920655: : Data start: 90801a Data end: 908044 irq/131-iwlwifi-710 [003] .... 908.920661: : Constant: 1 [...] I attached the config I used just in case you want to try building 4.12.8 kernel whether that changes anything. Would be interesting to see.
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