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

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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>
This commit is contained in:
Arnaldo Carvalho de Melo 2019-07-09 16:36:45 -03:00
parent d3280ce01e
commit c3e78a3403
1 changed files with 10 additions and 0 deletions
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10
tools/perf/builtin-trace.c
View File

@ -19,6 +19,7 @@
#include <api/fs/tracing_path.h>
#include <bpf/bpf.h>
#include "util/bpf_map.h"
#include "util/rlimit.h"
#include "builtin.h"
#include "util/cgroup.h"
#include "util/color.h"
@ -3864,6 +3865,15 @@ int cmd_trace(int argc, const char **argv)
goto out;
}
/*
* Parsing .perfconfig may entail creating a BPF event, that may need
* to create BPF maps, so bump RLIM_MEMLOCK as the default 64K setting
* is too small. This affects just this process, not touching the
* global setting. If it fails we'll get something in 'perf trace -v'
* to help diagnose the problem.
*/
rlimit__bump_memlock();
err = perf_config(trace__config, &trace);
if (err)
goto out;