libbpf-tools/profile: Add support for PID-namespacing #5152
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ekyooo
requested review from
drzaeus77,
goldshtn,
yonghong-song,
4ast,
brendangregg and
davemarchevsky
as code owners
Add PID translation for nested PID namespace environments, such as container.
Skip PID namespace translation on kernels prior to version 5.7, as bpf_get_ns_current_pid_tgid() is available starting from the 5.7 kernel.
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libbpf-tools/profile.c
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| @@ -595,6 +610,8 @@ int main(int argc, char **argv) | |||
| env.perf_max_stack_depth * sizeof(unsigned long)); | |||
| bpf_map__set_max_entries(obj->maps.stackmap, env.stack_storage_size); | |||
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| set_pidns(obj); | |||
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You can catch the returned value and show a warning message in case PID namespace does not exist?
| if (kernel_at_least(5, 7)) | ||
| return -EPERM; |
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The problem with fixed version check is that they will not work on kernel where a specific patch could have been backported.
Is there a way to rather check for the existence of a given bpf helper?
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In bcc/tools, we have a few cases (including profile) checking kernel version for bpf_get_ns_current_pid_tgid() availability. But for libbpf-tools, I think we can do better.
See trace_helpers.c. There are a few probe_*() functions which tries to detect whether a particular feature (prog_type, map_type) is supported or not. I think we can have another probe function to check whether bpf_get_ns_current_pid_tgid() is supported or not.
| @@ -595,6 +631,10 @@ int main(int argc, char **argv) | |||
| env.perf_max_stack_depth * sizeof(unsigned long)); | |||
| bpf_map__set_max_entries(obj->maps.stackmap, env.stack_storage_size); | |||
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| err = set_pidns(obj); | |||
| if (err) | |||
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Let us do 'err && env.verbose' here. We want to print out the below information under verbose mode.
| if (kernel_at_least(5, 7)) | ||
| return -EPERM; |
There was a problem hiding this comment.
In bcc/tools, we have a few cases (including profile) checking kernel version for bpf_get_ns_current_pid_tgid() availability. But for libbpf-tools, I think we can do better.
See trace_helpers.c. There are a few probe_*() functions which tries to detect whether a particular feature (prog_type, map_type) is supported or not. I think we can have another probe function to check whether bpf_get_ns_current_pid_tgid() is supported or not.
Support PID namespace translation as memleak.py does.