From 77d0871c76bad1093a3d86870fe76dd1ad0ca397 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Fri, 11 Aug 2017 16:26:19 -0700 Subject: [PATCH] perf bpf: Tighten detection of BPF events perf stat -e cpu/uops_executed.core,cmask=1/ would be detected as a BPF source event because the .c matches the .c source BPF pattern. v2: Originally I tried to use lex lookahead, but it doesn't seem to work. This now extends the BPF pattern to match longer events, but then does an extra check in the C code to reject BPF matches that do not end with .c/.o/.obj This uses REJECT, which makes the flex scanner slower, but that shouldn't be a big problem for the perf events. Committer testing: # perf trace -e write -e /home/acme/bpf/tracepoint.c cat /etc/passwd > /dev/null 0.000 ( 0.006 ms): cat/18485 write(fd: 1, buf: 0x7f59eebe1000, count: 3494 ) ... 0.006 ( ): raw_syscalls:sys_enter:NR 1 (1, 7f59eebe1000, da6, 22, 7f59eebe0010, 0)) 0.008 ( ): perf_bpf_probe:_write:(ffffffff9626b2c0)) 0.000 ( 0.010 ms): cat/18485 ... [continued]: write()) = 3494 # It continues doing what was expected, i.e. identifying /home/acme/bpf/tracepoint.c as a BPF event and activates the clang machinery to build an eBPF object and then uses sys_bpf() to hook it up to the raw_syscalls:sys_enter tracepoint, etc. Andi forgot to add Wang to the CC list, fix it. Signed-off-by: Andi Kleen Acked-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Wang Nan Link: http://lkml.kernel.org/r/20170811232634.30465-4-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/parse-events.l | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l index 660fca05bc93..c42edeac451f 100644 --- a/tools/perf/util/parse-events.l +++ b/tools/perf/util/parse-events.l @@ -53,6 +53,21 @@ static int str(yyscan_t scanner, int token) return token; } +static bool isbpf(yyscan_t scanner) +{ + char *text = parse_events_get_text(scanner); + int len = strlen(text); + + if (len < 2) + return false; + if ((text[len - 1] == 'c' || text[len - 1] == 'o') && + text[len - 2] == '.') + return true; + if (len > 4 && !strcmp(text + len - 4, ".obj")) + return true; + return false; +} + /* * This function is called when the parser gets two kind of input: * @@ -136,8 +151,8 @@ do { \ group [^,{}/]*[{][^}]*[}][^,{}/]* event_pmu [^,{}/]+[/][^/]*[/][^,{}/]* event [^,{}/]+ -bpf_object [^,{}]+\.(o|bpf) -bpf_source [^,{}]+\.c +bpf_object [^,{}]+\.(o|bpf)[a-zA-Z0-9._]* +bpf_source [^,{}]+\.c[a-zA-Z0-9._]* num_dec [0-9]+ num_hex 0x[a-fA-F0-9]+ @@ -307,8 +322,8 @@ r{num_raw_hex} { return raw(yyscanner); } {num_hex} { return value(yyscanner, 16); } {modifier_event} { return str(yyscanner, PE_MODIFIER_EVENT); } -{bpf_object} { return str(yyscanner, PE_BPF_OBJECT); } -{bpf_source} { return str(yyscanner, PE_BPF_SOURCE); } +{bpf_object} { if (!isbpf(yyscanner)) REJECT; return str(yyscanner, PE_BPF_OBJECT); } +{bpf_source} { if (!isbpf(yyscanner)) REJECT; return str(yyscanner, PE_BPF_SOURCE); } {name} { return pmu_str_check(yyscanner); } "/" { BEGIN(config); return '/'; } - { return '-'; } -- 2.20.1