x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 450 insertions, 0 deletions

diff --git a/drivers/misc/tsl2550.c b/drivers/misc/tsl2550.c
new file mode 100644
index 000000000..c871ea860
--- /dev/null
+++ b/drivers/misc/tsl2550.c
@@ -0,0 +1,450 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  tsl2550.c - Linux kernel modules for ambient light sensor
+ *
+ *  Copyright (C) 2007 Rodolfo Giometti <giometti@linux.it>
+ *  Copyright (C) 2007 Eurotech S.p.A. <info@eurotech.it>
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+
+#define TSL2550_DRV_NAME	"tsl2550"
+#define DRIVER_VERSION		"1.2"
+
+/*
+ * Defines
+ */
+
+#define TSL2550_POWER_DOWN		0x00
+#define TSL2550_POWER_UP		0x03
+#define TSL2550_STANDARD_RANGE		0x18
+#define TSL2550_EXTENDED_RANGE		0x1d
+#define TSL2550_READ_ADC0		0x43
+#define TSL2550_READ_ADC1		0x83
+
+/*
+ * Structs
+ */
+
+struct tsl2550_data {
+	struct i2c_client *client;
+	struct mutex update_lock;
+
+	unsigned int power_state:1;
+	unsigned int operating_mode:1;
+};
+
+/*
+ * Global data
+ */
+
+static const u8 TSL2550_MODE_RANGE[2] = {
+	TSL2550_STANDARD_RANGE, TSL2550_EXTENDED_RANGE,
+};
+
+/*
+ * Management functions
+ */
+
+static int tsl2550_set_operating_mode(struct i2c_client *client, int mode)
+{
+	struct tsl2550_data *data = i2c_get_clientdata(client);
+
+	int ret = i2c_smbus_write_byte(client, TSL2550_MODE_RANGE[mode]);
+
+	data->operating_mode = mode;
+
+	return ret;
+}
+
+static int tsl2550_set_power_state(struct i2c_client *client, int state)
+{
+	struct tsl2550_data *data = i2c_get_clientdata(client);
+	int ret;
+
+	if (state == 0)
+		ret = i2c_smbus_write_byte(client, TSL2550_POWER_DOWN);
+	else {
+		ret = i2c_smbus_write_byte(client, TSL2550_POWER_UP);
+
+		/* On power up we should reset operating mode also... */
+		tsl2550_set_operating_mode(client, data->operating_mode);
+	}
+
+	data->power_state = state;
+
+	return ret;
+}
+
+static int tsl2550_get_adc_value(struct i2c_client *client, u8 cmd)
+{
+	int ret;
+
+	ret = i2c_smbus_read_byte_data(client, cmd);
+	if (ret < 0)
+		return ret;
+	if (!(ret & 0x80))
+		return -EAGAIN;
+	return ret & 0x7f;	/* remove the "valid" bit */
+}
+
+/*
+ * LUX calculation
+ */
+
+#define	TSL2550_MAX_LUX		1846
+
+static const u8 ratio_lut[] = {
+	100, 100, 100, 100, 100, 100, 100, 100,
+	100, 100, 100, 100, 100, 100, 99, 99,
+	99, 99, 99, 99, 99, 99, 99, 99,
+	99, 99, 99, 98, 98, 98, 98, 98,
+	98, 98, 97, 97, 97, 97, 97, 96,
+	96, 96, 96, 95, 95, 95, 94, 94,
+	93, 93, 93, 92, 92, 91, 91, 90,
+	89, 89, 88, 87, 87, 86, 85, 84,
+	83, 82, 81, 80, 79, 78, 77, 75,
+	74, 73, 71, 69, 68, 66, 64, 62,
+	60, 58, 56, 54, 52, 49, 47, 44,
+	42, 41, 40, 40, 39, 39, 38, 38,
+	37, 37, 37, 36, 36, 36, 35, 35,
+	35, 35, 34, 34, 34, 34, 33, 33,
+	33, 33, 32, 32, 32, 32, 32, 31,
+	31, 31, 31, 31, 30, 30, 30, 30,
+	30,
+};
+
+static const u16 count_lut[] = {
+	0, 1, 2, 3, 4, 5, 6, 7,
+	8, 9, 10, 11, 12, 13, 14, 15,
+	16, 18, 20, 22, 24, 26, 28, 30,
+	32, 34, 36, 38, 40, 42, 44, 46,
+	49, 53, 57, 61, 65, 69, 73, 77,
+	81, 85, 89, 93, 97, 101, 105, 109,
+	115, 123, 131, 139, 147, 155, 163, 171,
+	179, 187, 195, 203, 211, 219, 227, 235,
+	247, 263, 279, 295, 311, 327, 343, 359,
+	375, 391, 407, 423, 439, 455, 471, 487,
+	511, 543, 575, 607, 639, 671, 703, 735,
+	767, 799, 831, 863, 895, 927, 959, 991,
+	1039, 1103, 1167, 1231, 1295, 1359, 1423, 1487,
+	1551, 1615, 1679, 1743, 1807, 1871, 1935, 1999,
+	2095, 2223, 2351, 2479, 2607, 2735, 2863, 2991,
+	3119, 3247, 3375, 3503, 3631, 3759, 3887, 4015,
+};
+
+/*
+ * This function is described into Taos TSL2550 Designer's Notebook
+ * pages 2, 3.
+ */
+static int tsl2550_calculate_lux(u8 ch0, u8 ch1)
+{
+	unsigned int lux;
+
+	/* Look up count from channel values */
+	u16 c0 = count_lut[ch0];
+	u16 c1 = count_lut[ch1];
+
+	/* Avoid division by 0 and count 1 cannot be greater than count 0 */
+	if (c1 <= c0)
+		if (c0) {
+			/*
+			 * Calculate ratio.
+			 * Note: the "128" is a scaling factor
+			 */
+			u8 r = c1 * 128 / c0;
+
+			/* Calculate LUX */
+			lux = ((c0 - c1) * ratio_lut[r]) / 256;
+		} else
+			lux = 0;
+	else
+		return 0;
+
+	/* LUX range check */
+	return lux > TSL2550_MAX_LUX ? TSL2550_MAX_LUX : lux;
+}
+
+/*
+ * SysFS support
+ */
+
+static ssize_t tsl2550_show_power_state(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct tsl2550_data *data = i2c_get_clientdata(to_i2c_client(dev));
+
+	return sprintf(buf, "%u\n", data->power_state);
+}
+
+static ssize_t tsl2550_store_power_state(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct tsl2550_data *data = i2c_get_clientdata(client);
+	unsigned long val;
+	int ret;
+
+	if (kstrtoul(buf, 10, &val) || val > 1)
+		return -EINVAL;
+
+	mutex_lock(&data->update_lock);
+	ret = tsl2550_set_power_state(client, val);
+	mutex_unlock(&data->update_lock);
+
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
+		   tsl2550_show_power_state, tsl2550_store_power_state);
+
+static ssize_t tsl2550_show_operating_mode(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct tsl2550_data *data = i2c_get_clientdata(to_i2c_client(dev));
+
+	return sprintf(buf, "%u\n", data->operating_mode);
+}
+
+static ssize_t tsl2550_store_operating_mode(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct tsl2550_data *data = i2c_get_clientdata(client);
+	unsigned long val;
+	int ret;
+
+	if (kstrtoul(buf, 10, &val) || val > 1)
+		return -EINVAL;
+
+	if (data->power_state == 0)
+		return -EBUSY;
+
+	mutex_lock(&data->update_lock);
+	ret = tsl2550_set_operating_mode(client, val);
+	mutex_unlock(&data->update_lock);
+
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static DEVICE_ATTR(operating_mode, S_IWUSR | S_IRUGO,
+		   tsl2550_show_operating_mode, tsl2550_store_operating_mode);
+
+static ssize_t __tsl2550_show_lux(struct i2c_client *client, char *buf)
+{
+	struct tsl2550_data *data = i2c_get_clientdata(client);
+	u8 ch0, ch1;
+	int ret;
+
+	ret = tsl2550_get_adc_value(client, TSL2550_READ_ADC0);
+	if (ret < 0)
+		return ret;
+	ch0 = ret;
+
+	ret = tsl2550_get_adc_value(client, TSL2550_READ_ADC1);
+	if (ret < 0)
+		return ret;
+	ch1 = ret;
+
+	/* Do the job */
+	ret = tsl2550_calculate_lux(ch0, ch1);
+	if (ret < 0)
+		return ret;
+	if (data->operating_mode == 1)
+		ret *= 5;
+
+	return sprintf(buf, "%d\n", ret);
+}
+
+static ssize_t tsl2550_show_lux1_input(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct tsl2550_data *data = i2c_get_clientdata(client);
+	int ret;
+
+	/* No LUX data if not operational */
+	if (!data->power_state)
+		return -EBUSY;
+
+	mutex_lock(&data->update_lock);
+	ret = __tsl2550_show_lux(client, buf);
+	mutex_unlock(&data->update_lock);
+
+	return ret;
+}
+
+static DEVICE_ATTR(lux1_input, S_IRUGO,
+		   tsl2550_show_lux1_input, NULL);
+
+static struct attribute *tsl2550_attributes[] = {
+	&dev_attr_power_state.attr,
+	&dev_attr_operating_mode.attr,
+	&dev_attr_lux1_input.attr,
+	NULL
+};
+
+static const struct attribute_group tsl2550_attr_group = {
+	.attrs = tsl2550_attributes,
+};
+
+/*
+ * Initialization function
+ */
+
+static int tsl2550_init_client(struct i2c_client *client)
+{
+	struct tsl2550_data *data = i2c_get_clientdata(client);
+	int err;
+
+	/*
+	 * Probe the chip. To do so we try to power up the device and then to
+	 * read back the 0x03 code
+	 */
+	err = i2c_smbus_read_byte_data(client, TSL2550_POWER_UP);
+	if (err < 0)
+		return err;
+	if (err != TSL2550_POWER_UP)
+		return -ENODEV;
+	data->power_state = 1;
+
+	/* Set the default operating mode */
+	err = i2c_smbus_write_byte(client,
+				   TSL2550_MODE_RANGE[data->operating_mode]);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+/*
+ * I2C init/probing/exit functions
+ */
+
+static struct i2c_driver tsl2550_driver;
+static int tsl2550_probe(struct i2c_client *client)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	struct tsl2550_data *data;
+	int *opmode, err = 0;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE
+					    | I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
+		err = -EIO;
+		goto exit;
+	}
+
+	data = kzalloc_obj(struct tsl2550_data);
+	if (!data) {
+		err = -ENOMEM;
+		goto exit;
+	}
+	data->client = client;
+	i2c_set_clientdata(client, data);
+
+	/* Check platform data */
+	opmode = client->dev.platform_data;
+	if (opmode) {
+		if (*opmode < 0 || *opmode > 1) {
+			dev_err(&client->dev, "invalid operating_mode (%d)\n",
+					*opmode);
+			err = -EINVAL;
+			goto exit_kfree;
+		}
+		data->operating_mode = *opmode;
+	} else
+		data->operating_mode = 0;	/* default mode is standard */
+	dev_info(&client->dev, "%s operating mode\n",
+			data->operating_mode ? "extended" : "standard");
+
+	mutex_init(&data->update_lock);
+
+	/* Initialize the TSL2550 chip */
+	err = tsl2550_init_client(client);
+	if (err)
+		goto exit_kfree;
+
+	/* Register sysfs hooks */
+	err = sysfs_create_group(&client->dev.kobj, &tsl2550_attr_group);
+	if (err)
+		goto exit_kfree;
+
+	dev_info(&client->dev, "support ver. %s enabled\n", DRIVER_VERSION);
+
+	return 0;
+
+exit_kfree:
+	kfree(data);
+exit:
+	return err;
+}
+
+static void tsl2550_remove(struct i2c_client *client)
+{
+	sysfs_remove_group(&client->dev.kobj, &tsl2550_attr_group);
+
+	/* Power down the device */
+	tsl2550_set_power_state(client, 0);
+
+	kfree(i2c_get_clientdata(client));
+}
+
+#ifdef CONFIG_PM_SLEEP
+
+static int tsl2550_suspend(struct device *dev)
+{
+	return tsl2550_set_power_state(to_i2c_client(dev), 0);
+}
+
+static int tsl2550_resume(struct device *dev)
+{
+	return tsl2550_set_power_state(to_i2c_client(dev), 1);
+}
+
+static SIMPLE_DEV_PM_OPS(tsl2550_pm_ops, tsl2550_suspend, tsl2550_resume);
+#define TSL2550_PM_OPS (&tsl2550_pm_ops)
+
+#else
+
+#define TSL2550_PM_OPS NULL
+
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct i2c_device_id tsl2550_id[] = {
+	{ .name = "tsl2550" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, tsl2550_id);
+
+static const struct of_device_id tsl2550_of_match[] = {
+	{ .compatible = "taos,tsl2550" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, tsl2550_of_match);
+
+static struct i2c_driver tsl2550_driver = {
+	.driver = {
+		.name	= TSL2550_DRV_NAME,
+		.of_match_table = tsl2550_of_match,
+		.pm	= TSL2550_PM_OPS,
+	},
+	.probe = tsl2550_probe,
+	.remove	= tsl2550_remove,
+	.id_table = tsl2550_id,
+};
+
+module_i2c_driver(tsl2550_driver);
+
+MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
+MODULE_DESCRIPTION("TSL2550 ambient light sensor driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRIVER_VERSION);