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 --- lib/test_memcat_p.c | 116 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 116 insertions(+) create mode 100644 lib/test_memcat_p.c (limited to 'lib/test_memcat_p.c') diff --git a/lib/test_memcat_p.c b/lib/test_memcat_p.c new file mode 100644 index 000000000..62f1633b3 --- /dev/null +++ b/lib/test_memcat_p.c @@ -0,0 +1,116 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Test cases for memcat_p() in lib/memcat_p.c + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include + +struct test_struct { + int num; + unsigned int magic; +}; + +#define MAGIC 0xf00ff00f +/* Size of each of the NULL-terminated input arrays */ +#define INPUT_MAX 128 +/* Expected number of non-NULL elements in the output array */ +#define EXPECT (INPUT_MAX * 2 - 2) + +static int __init test_memcat_p_init(void) +{ + struct test_struct **in0, **in1, **out, **p; + int err = -ENOMEM, i, r, total = 0; + + in0 = kzalloc_objs(*in0, INPUT_MAX); + if (!in0) + return err; + + in1 = kzalloc_objs(*in1, INPUT_MAX); + if (!in1) + goto err_free_in0; + + for (i = 0, r = 1; i < INPUT_MAX - 1; i++) { + in0[i] = kmalloc_obj(**in0); + if (!in0[i]) + goto err_free_elements; + + in1[i] = kmalloc_obj(**in1); + if (!in1[i]) { + kfree(in0[i]); + goto err_free_elements; + } + + /* lifted from test_sort.c */ + r = (r * 725861) % 6599; + in0[i]->num = r; + in1[i]->num = -r; + in0[i]->magic = MAGIC; + in1[i]->magic = MAGIC; + } + + in0[i] = in1[i] = NULL; + + out = memcat_p(in0, in1); + if (!out) + goto err_free_all_elements; + + err = -EINVAL; + for (i = 0, p = out; *p && (i < INPUT_MAX * 2 - 1); p++, i++) { + total += (*p)->num; + + if ((*p)->magic != MAGIC) { + pr_err("test failed: wrong magic at %d: %u\n", i, + (*p)->magic); + goto err_free_out; + } + } + + if (total) { + pr_err("test failed: expected zero total, got %d\n", total); + goto err_free_out; + } + + if (i != EXPECT) { + pr_err("test failed: expected output size %d, got %d\n", + EXPECT, i); + goto err_free_out; + } + + for (i = 0; i < INPUT_MAX - 1; i++) + if (out[i] != in0[i] || out[i + INPUT_MAX - 1] != in1[i]) { + pr_err("test failed: wrong element order at %d\n", i); + goto err_free_out; + } + + err = 0; + pr_info("test passed\n"); + +err_free_out: + kfree(out); +err_free_all_elements: + i = INPUT_MAX; +err_free_elements: + for (i--; i >= 0; i--) { + kfree(in1[i]); + kfree(in0[i]); + } + + kfree(in1); +err_free_in0: + kfree(in0); + + return err; +} + +static void __exit test_memcat_p_exit(void) +{ +} + +module_init(test_memcat_p_init); +module_exit(test_memcat_p_exit); + +MODULE_DESCRIPTION("Test cases for memcat_p() in lib/memcat_p.c"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1