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/lib/subcmd/exec-cmd.c | 218 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 218 insertions(+) create mode 100644 tools/lib/subcmd/exec-cmd.c (limited to 'tools/lib/subcmd/exec-cmd.c') diff --git a/tools/lib/subcmd/exec-cmd.c b/tools/lib/subcmd/exec-cmd.c new file mode 100644 index 000000000..7739b5217 --- /dev/null +++ b/tools/lib/subcmd/exec-cmd.c @@ -0,0 +1,218 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include +#include +#include "subcmd-util.h" +#include "exec-cmd.h" +#include "subcmd-config.h" + +#define MAX_ARGS 32 +#define PATH_MAX 4096 + +static const char *argv_exec_path; +static const char *argv0_path; + +void exec_cmd_init(const char *exec_name, const char *prefix, + const char *exec_path, const char *exec_path_env) +{ + subcmd_config.exec_name = exec_name; + subcmd_config.prefix = prefix; + subcmd_config.exec_path = exec_path; + subcmd_config.exec_path_env = exec_path_env; + + /* Setup environment variable for invoked shell script. */ + setenv("PREFIX", prefix, 1); +} + +#define is_dir_sep(c) ((c) == '/') + +static int is_absolute_path(const char *path) +{ + return path[0] == '/'; +} + +static const char *get_pwd_cwd(char *buf, size_t sz) +{ + char *pwd; + struct stat cwd_stat, pwd_stat; + if (getcwd(buf, sz) == NULL) + return NULL; + pwd = getenv("PWD"); + if (pwd && strcmp(pwd, buf)) { + stat(buf, &cwd_stat); + if (!stat(pwd, &pwd_stat) && + pwd_stat.st_dev == cwd_stat.st_dev && + pwd_stat.st_ino == cwd_stat.st_ino) { + strlcpy(buf, pwd, sz); + } + } + return buf; +} + +static const char *make_nonrelative_path(char *buf, size_t sz, const char *path) +{ + if (is_absolute_path(path)) { + if (strlcpy(buf, path, sz) >= sz) + die("Too long path: %.*s", 60, path); + } else { + const char *cwd = get_pwd_cwd(buf, sz); + + if (!cwd) + die("Cannot determine the current working directory"); + + if (strlen(cwd) + strlen(path) + 2 >= sz) + die("Too long path: %.*s", 60, path); + + strcat(buf, "/"); + strcat(buf, path); + } + return buf; +} + +char *system_path(const char *path) +{ + char *buf = NULL; + + if (is_absolute_path(path)) + return strdup(path); + + astrcatf(&buf, "%s/%s", subcmd_config.prefix, path); + + return buf; +} + +const char *extract_argv0_path(const char *argv0) +{ + const char *slash; + + if (!argv0 || !*argv0) + return NULL; + slash = argv0 + strlen(argv0); + + while (argv0 <= slash && !is_dir_sep(*slash)) + slash--; + + if (slash >= argv0) { + argv0_path = strndup(argv0, slash - argv0); + return argv0_path ? slash + 1 : NULL; + } + + return argv0; +} + +void set_argv_exec_path(const char *exec_path) +{ + argv_exec_path = exec_path; + /* + * Propagate this setting to external programs. + */ + setenv(subcmd_config.exec_path_env, exec_path, 1); +} + + +/* Returns the highest-priority location to look for subprograms. */ +char *get_argv_exec_path(void) +{ + char *env; + + if (argv_exec_path) + return strdup(argv_exec_path); + + env = getenv(subcmd_config.exec_path_env); + if (env && *env) + return strdup(env); + + return system_path(subcmd_config.exec_path); +} + +static void add_path(char **out, const char *path) +{ + if (path && *path) { + if (is_absolute_path(path)) + astrcat(out, path); + else { + char buf[PATH_MAX]; + + astrcat(out, make_nonrelative_path(buf, sizeof(buf), path)); + } + + astrcat(out, ":"); + } +} + +void setup_path(void) +{ + const char *old_path = getenv("PATH"); + char *new_path = NULL; + char *tmp = get_argv_exec_path(); + + add_path(&new_path, tmp); + add_path(&new_path, argv0_path); + free(tmp); + + if (old_path) + astrcat(&new_path, old_path); + else + astrcat(&new_path, "/usr/local/bin:/usr/bin:/bin"); + + setenv("PATH", new_path, 1); + + free(new_path); +} + +static const char **prepare_exec_cmd(const char **argv) +{ + int argc; + const char **nargv; + + for (argc = 0; argv[argc]; argc++) + ; /* just counting */ + nargv = malloc(sizeof(*nargv) * (argc + 2)); + + nargv[0] = subcmd_config.exec_name; + for (argc = 0; argv[argc]; argc++) + nargv[argc + 1] = argv[argc]; + nargv[argc + 1] = NULL; + return nargv; +} + +int execv_cmd(const char **argv) { + const char **nargv = prepare_exec_cmd(argv); + + /* execvp() can only ever return if it fails */ + execvp(subcmd_config.exec_name, (char **)nargv); + + free(nargv); + return -1; +} + + +int execl_cmd(const char *cmd,...) +{ + int argc; + const char *argv[MAX_ARGS + 1]; + const char *arg; + va_list param; + + va_start(param, cmd); + argv[0] = cmd; + argc = 1; + while (argc < MAX_ARGS) { + arg = argv[argc++] = va_arg(param, char *); + if (!arg) + break; + } + va_end(param); + if (MAX_ARGS <= argc) { + fprintf(stderr, " Error: too many args to run %s\n", cmd); + return -1; + } + + argv[argc] = NULL; + return execv_cmd(argv); +} -- cgit v1.3.1