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/testing/selftests/sched/.gitignore | 1 + tools/testing/selftests/sched/Makefile | 14 + tools/testing/selftests/sched/config | 1 + tools/testing/selftests/sched/cs_prctl_test.c | 359 ++++++++++++++++++++++++++ 4 files changed, 375 insertions(+) create mode 100644 tools/testing/selftests/sched/.gitignore create mode 100644 tools/testing/selftests/sched/Makefile create mode 100644 tools/testing/selftests/sched/config create mode 100644 tools/testing/selftests/sched/cs_prctl_test.c (limited to 'tools/testing/selftests/sched') diff --git a/tools/testing/selftests/sched/.gitignore b/tools/testing/selftests/sched/.gitignore new file mode 100644 index 000000000..6996d4654 --- /dev/null +++ b/tools/testing/selftests/sched/.gitignore @@ -0,0 +1 @@ +cs_prctl_test diff --git a/tools/testing/selftests/sched/Makefile b/tools/testing/selftests/sched/Makefile new file mode 100644 index 000000000..099ee9213 --- /dev/null +++ b/tools/testing/selftests/sched/Makefile @@ -0,0 +1,14 @@ +# SPDX-License-Identifier: GPL-2.0+ + +ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep clang),) +CLANG_FLAGS += -no-integrated-as +endif + +CFLAGS += -O2 -Wall -g -I./ $(KHDR_INCLUDES) -Wl,-rpath=./ \ + $(CLANG_FLAGS) +LDLIBS += -lpthread + +TEST_GEN_FILES := cs_prctl_test +TEST_PROGS := cs_prctl_test + +include ../lib.mk diff --git a/tools/testing/selftests/sched/config b/tools/testing/selftests/sched/config new file mode 100644 index 000000000..1bb8bf6d7 --- /dev/null +++ b/tools/testing/selftests/sched/config @@ -0,0 +1 @@ +# empty diff --git a/tools/testing/selftests/sched/cs_prctl_test.c b/tools/testing/selftests/sched/cs_prctl_test.c new file mode 100644 index 000000000..52d97fae4 --- /dev/null +++ b/tools/testing/selftests/sched/cs_prctl_test.c @@ -0,0 +1,359 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Use the core scheduling prctl() to test core scheduling cookies control. + * + * Copyright (c) 2021 Oracle and/or its affiliates. + * Author: Chris Hyser + * + * + * This library is free software; you can redistribute it and/or modify it + * under the terms of version 2.1 of the GNU Lesser General Public License as + * published by the Free Software Foundation. + * + * This library is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License + * for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with this library; if not, see . + */ + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#if __GLIBC_PREREQ(2, 30) == 0 +#include +static pid_t gettid(void) +{ + return syscall(SYS_gettid); +} +#endif + +#ifndef PR_SCHED_CORE +#define PR_SCHED_CORE 62 +#define PR_SCHED_CORE_GET 0 +#define PR_SCHED_CORE_CREATE 1 /* create unique core_sched cookie */ +#define PR_SCHED_CORE_SHARE_TO 2 /* push core_sched cookie to pid */ +#define PR_SCHED_CORE_SHARE_FROM 3 /* pull core_sched cookie to pid */ +#define PR_SCHED_CORE_MAX 4 +#endif + +#define MAX_PROCESSES 128 +#define MAX_THREADS 128 + +static const char USAGE[] = "cs_prctl_test [options]\n" +" options:\n" +" -P : number of processes to create.\n" +" -T : number of threads per process to create.\n" +" -d : delay time to keep tasks alive.\n" +" -k : keep tasks alive until keypress.\n"; + +enum pid_type {PIDTYPE_PID = 0, PIDTYPE_TGID, PIDTYPE_PGID}; + +const int THREAD_CLONE_FLAGS = CLONE_THREAD | CLONE_SIGHAND | CLONE_FS | CLONE_VM | CLONE_FILES; + +struct child_args { + int num_threads; + int pfd[2]; + int cpid; + int thr_tids[MAX_THREADS]; +}; + +static struct child_args procs[MAX_PROCESSES]; +static int num_processes = 2; +static int need_cleanup; + +static int _prctl(int option, unsigned long arg2, unsigned long arg3, unsigned long arg4, + unsigned long arg5) +{ + int res; + + res = prctl(option, arg2, arg3, arg4, arg5); + printf("%d = prctl(%d, %ld, %ld, %ld, %lx)\n", res, option, (long)arg2, (long)arg3, + (long)arg4, arg5); + return res; +} + +#define STACK_SIZE (1024 * 1024) + +#define handle_error(msg) __handle_error(__FILE__, __LINE__, msg) +static void __handle_error(char *fn, int ln, char *msg) +{ + int pidx; + printf("(%s:%d) - ", fn, ln); + perror(msg); + if (need_cleanup) { + for (pidx = 0; pidx < num_processes; ++pidx) + kill(procs[pidx].cpid, 15); + need_cleanup = 0; + } + exit(EXIT_FAILURE); +} + +static void handle_usage(int rc, char *msg) +{ + puts(USAGE); + puts(msg); + putchar('\n'); + exit(rc); +} + +static unsigned long get_cs_cookie(int pid) +{ + unsigned long long cookie; + int ret; + + ret = prctl(PR_SCHED_CORE, PR_SCHED_CORE_GET, pid, PIDTYPE_PID, + (unsigned long)&cookie); + if (ret) { + printf("Not a core sched system\n"); + return -1UL; + } + + return cookie; +} + +static int child_func_thread(void __attribute__((unused))*arg) +{ + while (1) + usleep(20000); + return 0; +} + +static void create_threads(int num_threads, int thr_tids[]) +{ + void *child_stack; + pid_t tid; + int i; + + for (i = 0; i < num_threads; ++i) { + child_stack = malloc(STACK_SIZE); + if (!child_stack) + handle_error("child stack allocate"); + + tid = clone(child_func_thread, child_stack + STACK_SIZE, THREAD_CLONE_FLAGS, NULL); + if (tid == -1) + handle_error("clone thread"); + thr_tids[i] = tid; + } +} + +static int child_func_process(void *arg) +{ + struct child_args *ca = (struct child_args *)arg; + int ret; + + close(ca->pfd[0]); + + create_threads(ca->num_threads, ca->thr_tids); + + ret = write(ca->pfd[1], &ca->thr_tids, sizeof(int) * ca->num_threads); + if (ret == -1) + printf("write failed on pfd[%d] - error (%s)\n", + ca->pfd[1], strerror(errno)); + + close(ca->pfd[1]); + + while (1) + usleep(20000); + return 0; +} + +static unsigned char child_func_process_stack[STACK_SIZE]; + +void create_processes(int num_processes, int num_threads, struct child_args proc[]) +{ + pid_t cpid; + int i, ret; + + for (i = 0; i < num_processes; ++i) { + proc[i].num_threads = num_threads; + + if (pipe(proc[i].pfd) == -1) + handle_error("pipe() failed"); + + cpid = clone(child_func_process, child_func_process_stack + STACK_SIZE, + SIGCHLD, &proc[i]); + proc[i].cpid = cpid; + close(proc[i].pfd[1]); + } + + for (i = 0; i < num_processes; ++i) { + ret = read(proc[i].pfd[0], &proc[i].thr_tids, sizeof(int) * proc[i].num_threads); + if (ret == -1) + printf("read failed on proc[%d].pfd[0] error (%s)\n", + i, strerror(errno)); + close(proc[i].pfd[0]); + } +} + +void disp_processes(int num_processes, struct child_args proc[]) +{ + int i, j; + + printf("tid=%d, / tgid=%d / pgid=%d: %lx\n", gettid(), getpid(), getpgid(0), + get_cs_cookie(getpid())); + + for (i = 0; i < num_processes; ++i) { + printf(" tid=%d, / tgid=%d / pgid=%d: %lx\n", proc[i].cpid, proc[i].cpid, + getpgid(proc[i].cpid), get_cs_cookie(proc[i].cpid)); + for (j = 0; j < proc[i].num_threads; ++j) { + printf(" tid=%d, / tgid=%d / pgid=%d: %lx\n", proc[i].thr_tids[j], + proc[i].cpid, getpgid(0), get_cs_cookie(proc[i].thr_tids[j])); + } + } + puts("\n"); +} + +static int errors; + +#define validate(v) _validate(__LINE__, v, #v) +void _validate(int line, int val, char *msg) +{ + if (!val) { + ++errors; + printf("(%d) FAILED: %s\n", line, msg); + } else { + printf("(%d) PASSED: %s\n", line, msg); + } +} + +int main(int argc, char *argv[]) +{ + int keypress = 0; + int num_threads = 3; + int delay = 0; + int res = 0; + int pidx; + int pid; + int opt; + + while ((opt = getopt(argc, argv, ":hkT:P:d:")) != -1) { + switch (opt) { + case 'P': + num_processes = (int)strtol(optarg, NULL, 10); + break; + case 'T': + num_threads = (int)strtoul(optarg, NULL, 10); + break; + case 'd': + delay = (int)strtol(optarg, NULL, 10); + break; + case 'k': + keypress = 1; + break; + case 'h': + printf(USAGE); + exit(EXIT_SUCCESS); + default: + handle_usage(20, "unknown option"); + } + } + + if (num_processes < 1 || num_processes > MAX_PROCESSES) + handle_usage(1, "Bad processes value"); + + if (num_threads < 1 || num_threads > MAX_THREADS) + handle_usage(2, "Bad thread value"); + + if (keypress) + delay = -1; + + srand(time(NULL)); + + /* put into separate process group */ + if (setpgid(0, 0) != 0) + handle_error("process group"); + + printf("\n## Create a thread/process/process group hierarchy\n"); + create_processes(num_processes, num_threads, procs); + need_cleanup = 1; + disp_processes(num_processes, procs); + validate(get_cs_cookie(0) == 0); + + printf("\n## Set a cookie on entire process group\n"); + if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_CREATE, 0, PIDTYPE_PGID, 0) < 0) + handle_error("core_sched create failed -- PGID"); + disp_processes(num_processes, procs); + + validate(get_cs_cookie(0) != 0); + + /* get a random process pid */ + pidx = rand() % num_processes; + pid = procs[pidx].cpid; + + validate(get_cs_cookie(0) == get_cs_cookie(pid)); + validate(get_cs_cookie(0) == get_cs_cookie(procs[pidx].thr_tids[0])); + + printf("\n## Set a new cookie on entire process/TGID [%d]\n", pid); + if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_CREATE, pid, PIDTYPE_TGID, 0) < 0) + handle_error("core_sched create failed -- TGID"); + disp_processes(num_processes, procs); + + validate(get_cs_cookie(0) != get_cs_cookie(pid)); + validate(get_cs_cookie(pid) != 0); + validate(get_cs_cookie(pid) == get_cs_cookie(procs[pidx].thr_tids[0])); + + printf("\n## Copy the cookie of current/PGID[%d], to pid [%d] as PIDTYPE_PID\n", + getpid(), pid); + if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, pid, PIDTYPE_PID, 0) < 0) + handle_error("core_sched share to itself failed -- PID"); + disp_processes(num_processes, procs); + + validate(get_cs_cookie(0) == get_cs_cookie(pid)); + validate(get_cs_cookie(pid) != 0); + validate(get_cs_cookie(pid) != get_cs_cookie(procs[pidx].thr_tids[0])); + + printf("\n## Copy cookie from a thread [%d] to current/PGID [%d] as PIDTYPE_PID\n", + procs[pidx].thr_tids[0], getpid()); + if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_FROM, procs[pidx].thr_tids[0], + PIDTYPE_PID, 0) < 0) + handle_error("core_sched share from thread failed -- PID"); + disp_processes(num_processes, procs); + + validate(get_cs_cookie(0) == get_cs_cookie(procs[pidx].thr_tids[0])); + validate(get_cs_cookie(pid) != get_cs_cookie(procs[pidx].thr_tids[0])); + + printf("\n## Copy cookie from current [%d] to current as pidtype PGID\n", getpid()); + if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, 0, PIDTYPE_PGID, 0) < 0) + handle_error("core_sched share to self failed -- PGID"); + disp_processes(num_processes, procs); + + validate(get_cs_cookie(0) == get_cs_cookie(pid)); + validate(get_cs_cookie(pid) != 0); + validate(get_cs_cookie(pid) == get_cs_cookie(procs[pidx].thr_tids[0])); + + validate(_prctl(PR_SCHED_CORE, PR_SCHED_CORE_MAX, 0, PIDTYPE_PGID, 0) < 0 + && errno == EINVAL); + + validate(_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, 0, PIDTYPE_PGID, 1) < 0 + && errno == EINVAL); + + if (errors) { + printf("TESTS FAILED. errors: %d\n", errors); + res = 10; + } else { + printf("SUCCESS !!!\n"); + } + + if (keypress) + getchar(); + else + sleep(delay); + + for (pidx = 0; pidx < num_processes; ++pidx) + kill(procs[pidx].cpid, 15); + + return res; +} -- cgit v1.3.1