From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Rogers Subject: [PATCH v3 10/12] perf expr: print a debug message for division by zero Date: Thu, 30 Apr 2020 00:51:42 -0700 Message-ID: <20200430075144.132716-11-irogers@google.com> References: <20200430075144.132716-1-irogers@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: In-Reply-To: <20200430075144.132716-1-irogers@google.com> Sender: linux-kernel-owner@vger.kernel.org To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Kan Liang , Andi Kleen , Haiyan Song , Jin Yao , Song Liu , Ravi Bangoria , John Garry , Leo Yan , Adrian Hunter , Paul Clarke , linux-kernel@vger.kernel.org, kajoljain , linux-perf-users@vger.kernel.org Cc: Stephane Eranian , Ian Rogers List-Id: linux-perf-users.vger.kernel.org If an expression yields 0 and is then divided-by/modulus-by then the parsing aborts. Add a debug error message to better enable debugging when this happens. Signed-off-by: Ian Rogers --- tools/perf/util/expr.y | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/expr.y b/tools/perf/util/expr.y index 54260094b947..21e82a1e11a2 100644 --- a/tools/perf/util/expr.y +++ b/tools/perf/util/expr.y @@ -103,8 +103,18 @@ expr: NUMBER | expr '+' expr { $$ = $1 + $3; } | expr '-' expr { $$ = $1 - $3; } | expr '*' expr { $$ = $1 * $3; } - | expr '/' expr { if ($3 == 0) YYABORT; $$ = $1 / $3; } - | expr '%' expr { if ((long)$3 == 0) YYABORT; $$ = (long)$1 % (long)$3; } + | expr '/' expr { if ($3 == 0) { + pr_debug("division by zero\n"); + YYABORT; + } + $$ = $1 / $3; + } + | expr '%' expr { if ((long)$3 == 0) { + pr_debug("division by zero\n"); + YYABORT; + } + $$ = (long)$1 % (long)$3; + } | '-' expr %prec NEG { $$ = -$2; } | '(' if_expr ')' { $$ = $2; } | MIN '(' expr ',' expr ')' { $$ = $3 < $5 ? $3 : $5; } -- 2.26.2.303.gf8c07b1a785-goog