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/build/fixdep.c | 170 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 170 insertions(+) create mode 100644 tools/build/fixdep.c (limited to 'tools/build/fixdep.c') diff --git a/tools/build/fixdep.c b/tools/build/fixdep.c new file mode 100644 index 000000000..2501fea7a --- /dev/null +++ b/tools/build/fixdep.c @@ -0,0 +1,170 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * "Optimize" a list of dependencies as spit out by gcc -MD + * for the build framework. + * + * Original author: + * Copyright 2002 by Kai Germaschewski + * + * This code has been borrowed from kbuild's fixdep (scripts/basic/fixdep.c), + * Please check it for detailed explanation. This fixdep borow only the + * base transformation of dependecies without the CONFIG mangle. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +char *target; +char *depfile; +char *cmdline; + +static void usage(void) +{ + fprintf(stderr, "Usage: fixdep \n"); + exit(1); +} + +/* + * Print out the commandline prefixed with cmd_ := + */ +static void print_cmdline(void) +{ + printf("cmd_%s := %s\n\n", target, cmdline); +} + +/* + * Important: The below generated source_foo.o and deps_foo.o variable + * assignments are parsed not only by make, but also by the rather simple + * parser in scripts/mod/sumversion.c. + */ +static void parse_dep_file(void *map, size_t len) +{ + char *m = map; + char *end = m + len; + char *p; + char s[PATH_MAX]; + int is_target, has_target = 0; + int saw_any_target = 0; + int is_first_dep = 0; + + while (m < end) { + /* Skip any "white space" */ + while (m < end && (*m == ' ' || *m == '\\' || *m == '\n')) + m++; + /* Find next "white space" */ + p = m; + while (p < end && *p != ' ' && *p != '\\' && *p != '\n') + p++; + /* Is the token we found a target name? */ + is_target = (*(p-1) == ':'); + /* Don't write any target names into the dependency file */ + if (is_target) { + /* The /next/ file is the first dependency */ + is_first_dep = 1; + has_target = 1; + } else if (has_target) { + /* Save this token/filename */ + memcpy(s, m, p-m); + s[p - m] = 0; + + /* + * Do not list the source file as dependency, + * so that kbuild is not confused if a .c file + * is rewritten into .S or vice versa. Storing + * it in source_* is needed for modpost to + * compute srcversions. + */ + if (is_first_dep) { + /* + * If processing the concatenation of + * multiple dependency files, only + * process the first target name, which + * will be the original source name, + * and ignore any other target names, + * which will be intermediate temporary + * files. + */ + if (!saw_any_target) { + saw_any_target = 1; + printf("source_%s := %s\n\n", + target, s); + printf("deps_%s := \\\n", + target); + } + is_first_dep = 0; + } else + printf(" %s \\\n", s); + } + /* + * Start searching for next token immediately after the first + * "whitespace" character that follows this token. + */ + m = p + 1; + } + + if (!saw_any_target) { + fprintf(stderr, "fixdep: parse error; no targets found\n"); + exit(1); + } + + printf("\n%s: $(deps_%s)\n\n", target, target); + printf("$(deps_%s):\n", target); +} + +static void print_deps(void) +{ + struct stat st; + int fd; + void *map; + + fd = open(depfile, O_RDONLY); + if (fd < 0) { + fprintf(stderr, "fixdep: error opening depfile: "); + perror(depfile); + exit(2); + } + if (fstat(fd, &st) < 0) { + fprintf(stderr, "fixdep: error fstat'ing depfile: "); + perror(depfile); + exit(2); + } + if (st.st_size == 0) { + fprintf(stderr, "fixdep: %s is empty\n", depfile); + close(fd); + return; + } + map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); + if ((long) map == -1) { + perror("fixdep: mmap"); + close(fd); + return; + } + + parse_dep_file(map, st.st_size); + + munmap(map, st.st_size); + + close(fd); +} + +int main(int argc, char **argv) +{ + if (argc != 4) + usage(); + + depfile = argv[1]; + target = argv[2]; + cmdline = argv[3]; + + print_cmdline(); + print_deps(); + + return 0; +} -- cgit v1.3.1