[tip:perf/urgent] perf tools: Fix eBPF event specification parsing

From: tip-bot for Jiri Olsa
Date: Sat Nov 11 2017 - 03:15:19 EST


Commit-ID: a271bfaf30ce8f7f57c6b65c47bff6d306d0b758
Gitweb: https://git.kernel.org/tip/a271bfaf30ce8f7f57c6b65c47bff6d306d0b758
Author: Jiri Olsa <jolsa@xxxxxxxxxx>
AuthorDate: Thu, 9 Nov 2017 10:02:10 +0100
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Thu, 9 Nov 2017 10:10:58 -0300

perf tools: Fix eBPF event specification parsing

Looks like I've reached the new level of stupidity, adding missing braces.

Committer testing:

Given the following eBPF C filter, that will add a record when it
returns true, i.e. when the tv_nsec variable is > 2000ns, should be
built and installed via sys_bpf(), but fails to do so before this patch:

# cat filter.c
#include <uapi/linux/bpf.h>
#define SEC(NAME) __attribute__((section(NAME), used))

SEC("func=hrtimer_nanosleep rqtp->tv_nsec")
int func(void *ctx, int err, long nsec)
{
return nsec > 1000;
}
char _license[] SEC("license") = "GPL";
int _version SEC("version") = LINUX_VERSION_CODE;
#

# perf trace -e nanosleep,filter.c usleep 1
invalid or unsupported event: 'filter.c'
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
#

And works again after it is applied, the nothing is inserted when the co

# perf trace -e *sleep,filter.c usleep 1
0.000 ( 0.066 ms): usleep/23994 nanosleep(rqtp: 0x7ffead94a0d0) = 0
# perf trace -e *sleep,filter.c usleep 2
0.000 ( 0.008 ms): usleep/24378 nanosleep(rqtp: 0x7fffa021ba50) ...
0.008 ( ): perf_bpf_probe:func:(ffffffffb410cb30) tv_nsec=2000)
0.000 ( 0.066 ms): usleep/24378 ... [continued]: nanosleep()) = 0
#

The intent of 9445464bb831 is kept:

# perf stat -e 'cpu/uops_executed.core,krava/' true
event syntax error: '..cuted.core,krava/'
\___ unknown term

valid terms: cmask,pc,event,edge,in_tx,any,ldlat,inv,umask,in_tx_cp,offcore_rsp,config,config1,config2,name,period
Run 'perf list' for a list of valid events

Usage: perf stat [<options>] [<command>]

-e, --event <event> event selector. use 'perf list' to list available events
#
# perf stat -e 'cpu/uops_executed.core,period=1/' true

Performance counter stats for 'true':

808,332 cpu/uops_executed.core,period=1/

0.002997237 seconds time elapsed

#

Reported-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Fixes: 9445464bb831 ("perf tools: Unwind properly location after REJECT")
Link: http://lkml.kernel.org/n/tip-diea0ihbwpxfw6938huv3whj@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/parse-events.l | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index dc5f40e..0257295 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -340,8 +340,8 @@ r{num_raw_hex} { return raw(yyscanner); }
{num_hex} { return value(yyscanner, 16); }

{modifier_event} { return str(yyscanner, PE_MODIFIER_EVENT); }
-{bpf_object} { if (!isbpf(yyscanner)) USER_REJECT; return str(yyscanner, PE_BPF_OBJECT); }
-{bpf_source} { if (!isbpf(yyscanner)) USER_REJECT; return str(yyscanner, PE_BPF_SOURCE); }
+{bpf_object} { if (!isbpf(yyscanner)) { USER_REJECT }; return str(yyscanner, PE_BPF_OBJECT); }
+{bpf_source} { if (!isbpf(yyscanner)) { USER_REJECT }; return str(yyscanner, PE_BPF_SOURCE); }
{name} { return pmu_str_check(yyscanner); }
"/" { BEGIN(config); return '/'; }
- { return '-'; }