Messages in this thread | ![/](/images/icornerl.gif) | | From | Wang Nan <> | Subject | [PATCH 0/5] perf bpf: Improve error code delivering and output | Date | Tue, 3 Nov 2015 10:44:41 +0000 |
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This patchset is based on tip/core.
Arnaldo found some confusing error reports when reviewing BPF related patches. This patch set makes some changes:
- perf test only print ok, failed or skip. Extra messages can be seen by '-v'.
- libbpf not output anything when called from perf without '-v'.
- Create libbpf and bpf-loader specific error number group to deliver precise error. New strerror framework makes adding new error code easier.
- Improve error messages.
After applying this patch:
When target object not exist:
$ ls ./foo.o ls: cannot access ./foo.o: No such file or directory $ ./perf record --event foo.o sleep event syntax error: 'foo.o' \___ Failed to load foo.o: No such file or directory
(add -v to see detail) Run 'perf list' for a list of valid events
Usage: perf record [<options>] [<command>] or: perf record [<options>] -- <command> [<options>]
-e, --event <event> event selector. use 'perf list' to list available events
When target object format invalid:
$ cp /etc/passwd ./badbpf.o $ ./perf record --event ./badbpf.o sleep event syntax error: './badbpf.o' \___ Failed to load ./badbpf.o: BPF object format invalid (... skip ...)
When run by normal user and /proc/sys/kernel/kptr_restrict is 1:
$ cat /proc/sys/kernel/kptr_restrict 1 $ ./perf record --event ./bpf-script-example.o sleep Failed to init vmlinux path. event syntax error: './bpf-script-example.o' \___ You need to be root, and /proc/sys/kernel/kptr_restrict should be 0 (... skip ...)
After fixing /proc/sys/kernel/kptr_restrict:
$ sudo -s # echo 0 > /proc/sys/kernel/kptr_restrict # exit $ ./perf record --event ./bpf-script-example.o sleep Failed to open kprobe_events: Permission denied event syntax error: './bpf-script-example.o' \___ You need to be root (... skip ...)
Load an object with no 'version' section:
# ./perf record --event ./bpf-script-example.o sleep event syntax error: './bpf-script-example.o' \___ Failed to load ./bpf-script-example.o: 'version' section incorrect or lost (... skip ...)
Load an object with incorrect 'version' section: # ./perf record --event ./bpf-script-example.o sleep event syntax error: './bpf-script-example.o' \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object (... skip ...)
When event name not set:
# ./perf record --event ./bpf-script-example.o sleep event syntax error: './bpf-script-example.o' \___ No event name found in config string (... skip ...)
Wang Nan (5): perf test: Keep test result clean if '-v' not set perf tools: Mute libbpf when '-v' not set perf tools: Parsing libbpf return value using err.h bpf tools: Improve libbpf error reporting perf tools: Improve BPF related error messages output
tools/lib/bpf/libbpf.c | 149 +++++++++++++++++++++++++------------ tools/lib/bpf/libbpf.h | 12 +++ tools/perf/tests/attr.c | 3 +- tools/perf/tests/code-reading.c | 8 +- tools/perf/tests/keep-tracking.c | 4 +- tools/perf/tests/llvm.c | 13 ++-- tools/perf/tests/switch-tracking.c | 4 +- tools/perf/util/bpf-loader.c | 110 +++++++++++++++++++++++---- tools/perf/util/bpf-loader.h | 18 +++++ tools/perf/util/parse-events.c | 7 +- 10 files changed, 243 insertions(+), 85 deletions(-)
-- 1.8.3.4
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