linux-imx

perf trace: Auto bump rlimit(MEMLOCK) for eBPF maps sake

Circa v5.2 this started to fail:

  # perf trace -e /wb/augmented_raw_syscalls.o
  event syntax error: '/wb/augmented_raw_syscalls.o'
                       \___ Operation not permitted

  (add -v to see detail)
  Run 'perf list' for a list of valid events

   Usage: perf trace [<options>] [<command>]
      or: perf trace [<options>] -- <command> [<options>]
      or: perf trace record [<options>] [<command>]
      or: perf trace record [<options>] -- <command> [<options>]

      -e, --event <event>   event/syscall selector. use 'perf list' to list available events
  #

In verbose mode we some -EPERM when creating a BPF map:

  # perf trace -v -e /wb/augmented_raw_syscalls.o
  <SNIP>
  libbpf: failed to create map (name: '__augmented_syscalls__'): Operation not permitted
  libbpf: failed to load object '/wb/augmented_raw_syscalls.o'
  bpf: load objects failed: err=-1: (Operation not permitted)
  event syntax error: '/wb/augmented_raw_syscalls.o'
                       \___ Operation not permitted

  (add -v to see detail)
  Run 'perf list' for a list of valid events

   Usage: perf trace [<options>] [<command>]
      or: perf trace [<options>] -- <command> [<options>]
      or: perf trace record [<options>] [<command>]
      or: perf trace record [<options>] -- <command> [<options>]

      -e, --event <event>   event/syscall selector. use 'perf list' to list available events
  #

If we bumped 'ulimit -l 128' to get it from the 64k default to double that, it
worked, so use the recently added rlimit__bump_memlock() helper:

  # perf trace -e /wb/augmented_raw_syscalls.o -e open*,*sleep sleep 1
       0.000 ( 0.007 ms): sleep/28042 openat(dfd: CWD, filename: "/etc/ld.so.cache", flags: RDONLY|CLOEXEC) = 3
       0.022 ( 0.004 ms): sleep/28042 openat(dfd: CWD, filename: "/lib64/libc.so.6", flags: RDONLY|CLOEXEC) = 3
       0.201 ( 0.007 ms): sleep/28042 openat(dfd: CWD, filename: "", flags: RDONLY|CLOEXEC)                 = 3
       0.241 (1000.421 ms): sleep/28042 nanosleep(rqtp: 0x7ffd6c3e6ed0)                                       = 0
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-j6f2ioa6hj9dinzpjvlhcjoc@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>