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13 June 2022, 11:31:42 UTC
Revision b5b1404d0815894de0690de8a1ab58269e56eae6 authored by Linus Torvalds on 12 August 2018, 19:19:42 UTC, committed by Linus Torvalds on 12 August 2018, 19:19:42 UTC 
init: rename and re-order boot_cpu_state_init()
 
This is purely a preparatory patch for upcoming changes during the 4.19
merge window.

We have a function called "boot_cpu_state_init()" that isn't really
about the bootup cpu state: that is done much earlier by the similarly
named "boot_cpu_init()" (note lack of "state" in name).

This function initializes some hotplug CPU state, and needs to run after
the percpu data has been properly initialized.  It even has a comment to
that effect.

Except it _doesn't_ actually run after the percpu data has been properly
initialized.  On x86 it happens to do that, but on at least arm and
arm64, the percpu base pointers are initialized by the arch-specific
'smp_prepare_boot_cpu()' hook, which ran _after_ boot_cpu_state_init().

This had some unexpected results, and in particular we have a patch
pending for the merge window that did the obvious cleanup of using
'this_cpu_write()' in the cpu hotplug init code:

  -       per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE;
  +       this_cpu_write(cpuhp_state.state, CPUHP_ONLINE);

which is obviously the right thing to do.  Except because of the
ordering issue, it actually failed miserably and unexpectedly on arm64.

So this just fixes the ordering, and changes the name of the function to
be 'boot_cpu_hotplug_init()' to make it obvious that it's about cpu
hotplug state, because the core CPU state was supposed to have already
been done earlier.

Marked for stable, since the (not yet merged) patch that will show this
problem is marked for stable.

Reported-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent d6dd643
Raw File
Tip revision: b5b1404d0815894de0690de8a1ab58269e56eae6 authored by Linus Torvalds on 12 August 2018, 19:19:42 UTC
init: rename and re-order boot_cpu_state_init()
Tip revision: b5b1404
test_uuid.c 
/*
 * Test cases for lib/uuid.c module.
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/uuid.h>

struct test_uuid_data {
	const char *uuid;
	guid_t le;
	uuid_t be;
};

static const struct test_uuid_data test_uuid_test_data[] = {
	{
		.uuid = "c33f4995-3701-450e-9fbf-206a2e98e576",
		.le = GUID_INIT(0xc33f4995, 0x3701, 0x450e, 0x9f, 0xbf, 0x20, 0x6a, 0x2e, 0x98, 0xe5, 0x76),
		.be = UUID_INIT(0xc33f4995, 0x3701, 0x450e, 0x9f, 0xbf, 0x20, 0x6a, 0x2e, 0x98, 0xe5, 0x76),
	},
	{
		.uuid = "64b4371c-77c1-48f9-8221-29f054fc023b",
		.le = GUID_INIT(0x64b4371c, 0x77c1, 0x48f9, 0x82, 0x21, 0x29, 0xf0, 0x54, 0xfc, 0x02, 0x3b),
		.be = UUID_INIT(0x64b4371c, 0x77c1, 0x48f9, 0x82, 0x21, 0x29, 0xf0, 0x54, 0xfc, 0x02, 0x3b),
	},
	{
		.uuid = "0cb4ddff-a545-4401-9d06-688af53e7f84",
		.le = GUID_INIT(0x0cb4ddff, 0xa545, 0x4401, 0x9d, 0x06, 0x68, 0x8a, 0xf5, 0x3e, 0x7f, 0x84),
		.be = UUID_INIT(0x0cb4ddff, 0xa545, 0x4401, 0x9d, 0x06, 0x68, 0x8a, 0xf5, 0x3e, 0x7f, 0x84),
	},
};

static const char * const test_uuid_wrong_data[] = {
	"c33f4995-3701-450e-9fbf206a2e98e576 ",	/* no hyphen(s) */
	"64b4371c-77c1-48f9-8221-29f054XX023b",	/* invalid character(s) */
	"0cb4ddff-a545-4401-9d06-688af53e",	/* not enough data */
};

static unsigned total_tests __initdata;
static unsigned failed_tests __initdata;

static void __init test_uuid_failed(const char *prefix, bool wrong, bool be,
				    const char *data, const char *actual)
{
	pr_err("%s test #%u %s %s data: '%s'\n",
	       prefix,
	       total_tests,
	       wrong ? "passed on wrong" : "failed on",
	       be ? "BE" : "LE",
	       data);
	if (actual && *actual)
		pr_err("%s test #%u actual data: '%s'\n",
		       prefix,
		       total_tests,
		       actual);
	failed_tests++;
}

static void __init test_uuid_test(const struct test_uuid_data *data)
{
	guid_t le;
	uuid_t be;
	char buf[48];

	/* LE */
	total_tests++;
	if (guid_parse(data->uuid, &le))
		test_uuid_failed("conversion", false, false, data->uuid, NULL);

	total_tests++;
	if (!guid_equal(&data->le, &le)) {
		sprintf(buf, "%pUl", &le);
		test_uuid_failed("cmp", false, false, data->uuid, buf);
	}

	/* BE */
	total_tests++;
	if (uuid_parse(data->uuid, &be))
		test_uuid_failed("conversion", false, true, data->uuid, NULL);

	total_tests++;
	if (!uuid_equal(&data->be, &be)) {
		sprintf(buf, "%pUb", &be);
		test_uuid_failed("cmp", false, true, data->uuid, buf);
	}
}

static void __init test_uuid_wrong(const char *data)
{
	guid_t le;
	uuid_t be;

	/* LE */
	total_tests++;
	if (!guid_parse(data, &le))
		test_uuid_failed("negative", true, false, data, NULL);

	/* BE */
	total_tests++;
	if (!uuid_parse(data, &be))
		test_uuid_failed("negative", true, true, data, NULL);
}

static int __init test_uuid_init(void)
{
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(test_uuid_test_data); i++)
		test_uuid_test(&test_uuid_test_data[i]);

	for (i = 0; i < ARRAY_SIZE(test_uuid_wrong_data); i++)
		test_uuid_wrong(test_uuid_wrong_data[i]);

	if (failed_tests == 0)
		pr_info("all %u tests passed\n", total_tests);
	else
		pr_err("failed %u out of %u tests\n", failed_tests, total_tests);

	return failed_tests ? -EINVAL : 0;
}
module_init(test_uuid_init);

static void __exit test_uuid_exit(void)
{
	/* do nothing */
}
module_exit(test_uuid_exit);

MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
MODULE_LICENSE("Dual BSD/GPL");
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