From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- tools/perf/util/expr.l | 150 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 150 insertions(+) create mode 100644 tools/perf/util/expr.l (limited to 'tools/perf/util/expr.l') diff --git a/tools/perf/util/expr.l b/tools/perf/util/expr.l new file mode 100644 index 000000000..f16ccff27 --- /dev/null +++ b/tools/perf/util/expr.l @@ -0,0 +1,150 @@ +%option prefix="expr_" +%option reentrant +%option bison-bridge + +%{ +#include +#include "expr.h" +#include "expr-bison.h" +#include + +char *expr_get_text(yyscan_t yyscanner); +YYSTYPE *expr_get_lval(yyscan_t yyscanner); + +static double __value(YYSTYPE *yylval, char *str, int token) +{ + double num; + + errno = 0; + num = strtod(str, NULL); + if (errno) + return EXPR_ERROR; + + yylval->num = num; + return token; +} + +static int value(yyscan_t scanner) +{ + YYSTYPE *yylval = expr_get_lval(scanner); + char *text = expr_get_text(scanner); + + return __value(yylval, text, NUMBER); +} + +/* + * Allow @ instead of / to be able to specify pmu/event/ without + * conflicts with normal division. + */ +static char *normalize(char *str, int runtime) +{ + char *ret = str; + char *dst = str; + + while (*str) { + if (*str == '\\') { + *dst++ = *++str; + if (!*str) + break; + } + else if (*str == '?') { + char *paramval; + int i = 0; + int size = asprintf(¶mval, "%d", runtime); + + if (size < 0) + *dst++ = '0'; + else { + while (i < size) + *dst++ = paramval[i++]; + free(paramval); + } + } + else + *dst++ = *str; + str++; + } + + *dst = 0x0; + return ret; +} + +static int str(yyscan_t scanner, int token, int runtime) +{ + YYSTYPE *yylval = expr_get_lval(scanner); + char *text = expr_get_text(scanner); + + yylval->str = normalize(strdup(text), runtime); + if (!yylval->str) + return EXPR_ERROR; + + yylval->str = normalize(yylval->str, runtime); + return token; +} + +static int literal(yyscan_t scanner, const struct expr_scanner_ctx *sctx) +{ + YYSTYPE *yylval = expr_get_lval(scanner); + + yylval->num = expr__get_literal(expr_get_text(scanner), sctx); + if (isnan(yylval->num)) { + if (!sctx->is_test) + return EXPR_ERROR; + yylval->num = 1; + } + return LITERAL; +} + +static int nan_value(yyscan_t scanner) +{ + YYSTYPE *yylval = expr_get_lval(scanner); + + yylval->num = NAN; + return NUMBER; +} +%} + +number ([0-9]+\.?[0-9]*|[0-9]*\.?[0-9]+)(e-?[0-9]+)? + +sch [-,=] +spec \\{sch} +sym [0-9a-zA-Z_\.:@?]+ +symbol ({spec}|{sym})+ +literal #[0-9a-zA-Z_\.\-]+ + +%% + struct expr_scanner_ctx *sctx = expr_get_extra(yyscanner); + +d_ratio { return D_RATIO; } +max { return MAX; } +min { return MIN; } +if { return IF; } +else { return ELSE; } +source_count { return SOURCE_COUNT; } +aggr_nr { return AGGR_NR; } +has_event { return HAS_EVENT; } +strcmp_cpuid_str { return STRCMP_CPUID_STR; } +NaN { return nan_value(yyscanner); } +{literal} { return literal(yyscanner, sctx); } +{number} { return value(yyscanner); } +{symbol} { return str(yyscanner, ID, sctx->runtime); } +"|" { return '|'; } +"^" { return '^'; } +"&" { return '&'; } +"<" { return '<'; } +">" { return '>'; } +"-" { return '-'; } +"+" { return '+'; } +"*" { return '*'; } +"/" { return '/'; } +"%" { return '%'; } +"(" { return '('; } +")" { return ')'; } +"," { return ','; } +. { } +%% + +int expr_wrap(void *scanner __maybe_unused) +{ + return 1; +} -- cgit v1.3.1