Tracing fixes to previous fixes:

Unfortunately, the last set of fixes introduced some minor bugs:
 
  - The bootconfig apply_xbc() leak fix caused the application to return
    a positive number on success, when it should have returned zero.
 
  - The preempt_irq_delay_thread fix to make the creation code
    wait for the kthread to finish to prevent it from executing after
    module unload, can now cause the kthread to exit before it even
    executes (preventing it to run its tests).
 
  - The fix to the bootconfig that fixed the initrd to remove the
    bootconfig from causing the kernel to panic, now prints a warning
    that the bootconfig is not found, even when bootconfig is not
    on the command line.
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Merge tag 'trace-v5.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "Fixes to previous fixes.

  Unfortunately, the last set of fixes introduced some minor bugs:

   - The bootconfig apply_xbc() leak fix caused the application to
     return a positive number on success, when it should have returned
     zero.

   - The preempt_irq_delay_thread fix to make the creation code wait for
     the kthread to finish to prevent it from executing after module
     unload, can now cause the kthread to exit before it even executes
     (preventing it to run its tests).

   - The fix to the bootconfig that fixed the initrd to remove the
     bootconfig from causing the kernel to panic, now prints a warning
     that the bootconfig is not found, even when bootconfig is not on
     the command line"

* tag 'trace-v5.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  bootconfig: Fix to prevent warning message if no bootconfig option
  tracing: Wait for preempt irq delay thread to execute
  tools/bootconfig: Fix apply_xbc() to return zero on success

init/main.c

@@ -400,9 +400,8 @@ static void __init setup_boot_config(const char *cmdline)
 	char *data, *copy;
 	int ret;
 
+	/* Cut out the bootconfig data even if we have no bootconfig option */
 	data = get_boot_config_from_initrd(&size, &csum);
-	if (!data)
-		goto not_found;
 
 	strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
 	parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
@@ -411,6 +410,11 @@ static void __init setup_boot_config(const char *cmdline)
 	if (!bootconfig_found)
 		return;
 
+	if (!data) {
+		pr_err("'bootconfig' found on command line, but no bootconfig found\n");
+		return;
+	}
+
 	if (size >= XBC_DATA_MAX) {
 		pr_err("bootconfig size %d greater than max size %d\n",
 			size, XBC_DATA_MAX);
@@ -446,8 +450,6 @@ static void __init setup_boot_config(const char *cmdline)
 		extra_init_args = xbc_make_cmdline("init");
 	}
 	return;
-not_found:
-	pr_err("'bootconfig' found on command line, but no bootconfig found\n");
 }
 
 #else

kernel/trace/preemptirq_delay_test.c

@@ -16,6 +16,7 @@
 #include <linux/printk.h>
 #include <linux/string.h>
 #include <linux/sysfs.h>
+#include <linux/completion.h>
 
 static ulong delay = 100;
 static char test_mode[12] = "irq";
@@ -28,6 +29,8 @@ MODULE_PARM_DESC(delay, "Period in microseconds (100 us default)");
 MODULE_PARM_DESC(test_mode, "Mode of the test such as preempt, irq, or alternate (default irq)");
 MODULE_PARM_DESC(burst_size, "The size of a burst (default 1)");
 
+static struct completion done;
+
 #define MIN(x, y) ((x) < (y) ? (x) : (y))
 
 static void busy_wait(ulong time)
@@ -114,6 +117,8 @@ static int preemptirq_delay_run(void *data)
 	for (i = 0; i < s; i++)
 		(testfuncs[i])(i);
 
+	complete(&done);
+
 	set_current_state(TASK_INTERRUPTIBLE);
 	while (!kthread_should_stop()) {
 		schedule();
@@ -128,15 +133,18 @@ static int preemptirq_delay_run(void *data)
 static int preemptirq_run_test(void)
 {
 	struct task_struct *task;
-
 	char task_name[50];
 
+	init_completion(&done);
+
 	snprintf(task_name, sizeof(task_name), "%s_test", test_mode);
 	task =  kthread_run(preemptirq_delay_run, NULL, task_name);
 	if (IS_ERR(task))
 		return PTR_ERR(task);
-	if (task)
+	if (task) {
+		wait_for_completion(&done);
 		kthread_stop(task);
+	}
 	return 0;
 }
 

tools/bootconfig/main.c

@@ -337,6 +337,7 @@ int apply_xbc(const char *path, const char *xbc_path)
 		pr_err("Failed to apply a boot config magic: %d\n", ret);
 		goto out;
 	}
+	ret = 0;
 out:
 	close(fd);
 	free(data);