Use github.com/cilium/cilium/pkg/alignchecker to check C and Go structs offsets and sizes #28
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Asphaltt
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Sep 24, 2024
It fails to run with --filter-trace-tc: ```bash 2024/09/24 12:59:02 Attaching tc-bpf progs... 2024/09/24 12:59:02 failed to trace TC progs: failed to trace bpf progs: failed to find address for function entry2 of bpf prog SchedCLS(entry2)cilium#28 ``` Then, I fix it by extracting bpf prog name from /proc/kallsyms correctly, and avoid `addr - 1` for tracing XDP and tc-bpf. Signed-off-by: Leon Hwang <[email protected]>
Asphaltt
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Sep 24, 2024
It fails to run with --filter-trace-tc: ```bash 2024/09/24 12:59:02 Attaching tc-bpf progs... 2024/09/24 12:59:02 failed to trace TC progs: failed to trace bpf progs: failed to find address for function entry2 of bpf prog SchedCLS(entry2)cilium#28 ``` Then, I fix it by extracting bpf prog name from /proc/kallsyms correctly, and avoid `addr - 1` for tracing XDP and tc-bpf. ```bash 2024/09/24 13:00:49 Attaching tc-bpf progs... 2024/09/24 13:00:49 Attaching xdp progs... 2024/09/24 13:00:49 Attaching kprobes (via kprobe-multi)... 49 / 49 [--------------------------------------------------------------------------------------------------------------------------------------] 100.00% ? p/s 2024/09/24 13:00:49 Attached (ignored 0) 2024/09/24 13:00:49 Listening for events.. SKB CPU PROCESS NETNS MARK/x IFACE PROTO MTU LEN TUPLE FUNC 0xffff8e151d39b500 6 <empty>:0 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) entry1(tc) 0xffff8e151d39ab00 6 ~wru/pwru:437091 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) entry1(tc) 0xffff8e151d39a200 6 <empty>:0 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) entry1(tc) 0xffff8e151d39b100 6 <empty>:0 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) entry1(tc) ^C2024/09/24 13:01:04 Received signal, exiting program.. 2024/09/24 13:01:04 Detaching kprobes... 3 / 3 [---------------------------------------------------------------------------------------------------------------------------------------] 100.00% 52 p/s ``` Signed-off-by: Leon Hwang <[email protected]>
Asphaltt
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Sep 25, 2024
It fails to run with --filter-trace-tc: ```bash 2024/09/24 12:59:02 Attaching tc-bpf progs... 2024/09/24 12:59:02 failed to trace TC progs: failed to trace bpf progs: failed to find address for function entry2 of bpf prog SchedCLS(entry2)cilium#28 ``` Then, I fix it by extracting bpf prog name from /proc/kallsyms correctly, and avoid `addr - 1` for tracing XDP and tc-bpf. ```bash 2024/09/24 13:00:49 Attaching tc-bpf progs... 2024/09/24 13:00:49 Attaching xdp progs... 2024/09/24 13:00:49 Attaching kprobes (via kprobe-multi)... 49 / 49 [--------------------------------------------------------------------------------------------------------------------------------------] 100.00% ? p/s 2024/09/24 13:00:49 Attached (ignored 0) 2024/09/24 13:00:49 Listening for events.. SKB CPU PROCESS NETNS MARK/x IFACE PROTO MTU LEN TUPLE FUNC 0xffff8e151d39b500 6 <empty>:0 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) entry1(tc) 0xffff8e151d39ab00 6 ~wru/pwru:437091 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) entry1(tc) 0xffff8e151d39a200 6 <empty>:0 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) entry1(tc) 0xffff8e151d39b100 6 <empty>:0 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) entry1(tc) ^C2024/09/24 13:01:04 Received signal, exiting program.. 2024/09/24 13:01:04 Detaching kprobes... 3 / 3 [---------------------------------------------------------------------------------------------------------------------------------------] 100.00% 52 p/s ``` Signed-off-by: Leon Hwang <[email protected]>
Asphaltt
added a commit
to Asphaltt/pwru
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this issue
Sep 25, 2024
It fails to run with --filter-trace-tc: ```bash 2024/09/24 12:59:02 Attaching tc-bpf progs... 2024/09/24 12:59:02 failed to trace TC progs: failed to trace bpf progs: failed to find address for function entry2 of bpf prog SchedCLS(entry2)cilium#28 ``` Then, I fix it by matching prog ksym with prog tag. And avoid `addr - 1` for `--filter-trace-{tc,xdp}`. ```bash 2024/09/25 13:57:00 Attaching tc-bpf progs... 2024/09/25 13:57:00 Attaching kprobes (via kprobe-multi)... 49 / 49 [--------------------------------------------------------------------------------------------------------------------------------------] 100.00% ? p/s 2024/09/25 13:57:00 Attached (ignored 0) 2024/09/25 13:57:00 Listening for events.. SKB CPU PROCESS NETNS MARK/x IFACE PROTO MTU LEN TUPLE FUNC 0xffff8e151d39be00 6 <empty>:0 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) bpf_prog_e20a685998fd41c8_entry1[bpf](tc) 0xffff8e151d39a500 6 <empty>:0 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) bpf_prog_e20a685998fd41c8_entry1[bpf](tc) 0xffff8e151d39bd00 6 <empty>:0 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) bpf_prog_e20a685998fd41c8_entry1[bpf](tc) 0xffff8e151d39a200 6 <empty>:0 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) bpf_prog_e20a685998fd41c8_entry1[bpf](tc) 0xffff8e151d39a800 6 <empty>:0 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) bpf_prog_e20a685998fd41c8_entry1[bpf](tc) ^C2024/09/25 14:02:16 Received signal, exiting program.. 2024/09/25 14:02:16 Detaching kprobes... 3 / 3 [---------------------------------------------------------------------------------------------------------------------------------------] 100.00% 50 p/s ``` Signed-off-by: Leon Hwang <[email protected]>
brb
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Sep 26, 2024
It fails to run with --filter-trace-tc: ```bash 2024/09/24 12:59:02 Attaching tc-bpf progs... 2024/09/24 12:59:02 failed to trace TC progs: failed to trace bpf progs: failed to find address for function entry2 of bpf prog SchedCLS(entry2)#28 ``` Then, I fix it by matching prog ksym with prog tag. And avoid `addr - 1` for `--filter-trace-{tc,xdp}`. ```bash 2024/09/25 13:57:00 Attaching tc-bpf progs... 2024/09/25 13:57:00 Attaching kprobes (via kprobe-multi)... 49 / 49 [--------------------------------------------------------------------------------------------------------------------------------------] 100.00% ? p/s 2024/09/25 13:57:00 Attached (ignored 0) 2024/09/25 13:57:00 Listening for events.. SKB CPU PROCESS NETNS MARK/x IFACE PROTO MTU LEN TUPLE FUNC 0xffff8e151d39be00 6 <empty>:0 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) bpf_prog_e20a685998fd41c8_entry1[bpf](tc) 0xffff8e151d39a500 6 <empty>:0 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) bpf_prog_e20a685998fd41c8_entry1[bpf](tc) 0xffff8e151d39bd00 6 <empty>:0 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) bpf_prog_e20a685998fd41c8_entry1[bpf](tc) 0xffff8e151d39a200 6 <empty>:0 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) bpf_prog_e20a685998fd41c8_entry1[bpf](tc) 0xffff8e151d39a800 6 <empty>:0 4026531840 0 ens33:2 0x0800 1500 98 192.168.241.1:0->192.168.241.133:0(icmp) bpf_prog_e20a685998fd41c8_entry1[bpf](tc) ^C2024/09/25 14:02:16 Received signal, exiting program.. 2024/09/25 14:02:16 Detaching kprobes... 3 / 3 [---------------------------------------------------------------------------------------------------------------------------------------] 100.00% 50 p/s ``` Signed-off-by: Leon Hwang <[email protected]>
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Golang supports struct's host layout since go1.23 by structs.HostLayout. Would it be better to mark bpf2go-generated structs as host layout? |
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It will when ebpf-go targets 1.23, we always target the second-newest version. |
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The Cilium's alignchecker should be extended to support BTF instead of DWARF. AFAIK, @ti-mo is planning to do so.
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