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, 346 insertions, 0 deletions

diff --git a/drivers/mfd/adp5520.c b/drivers/mfd/adp5520.c
new file mode 100644
index 000000000..bd6f4965e
--- /dev/null
+++ b/drivers/mfd/adp5520.c
@@ -0,0 +1,346 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Base driver for Analog Devices ADP5520/ADP5501 MFD PMICs
+ * LCD Backlight: drivers/video/backlight/adp5520_bl
+ * LEDs		: drivers/led/leds-adp5520
+ * GPIO		: drivers/gpio/adp5520-gpio (ADP5520 only)
+ * Keys		: drivers/input/keyboard/adp5520-keys (ADP5520 only)
+ *
+ * Copyright 2009 Analog Devices Inc.
+ *
+ * Author: Michael Hennerich <michael.hennerich@analog.com>
+ *
+ * Derived from da903x:
+ * Copyright (C) 2008 Compulab, Ltd.
+ *	Mike Rapoport <mike@compulab.co.il>
+ *
+ * Copyright (C) 2006-2008 Marvell International Ltd.
+ *	Eric Miao <eric.miao@marvell.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+
+#include <linux/mfd/adp5520.h>
+
+struct adp5520_chip {
+	struct i2c_client *client;
+	struct device *dev;
+	struct mutex lock;
+	struct blocking_notifier_head notifier_list;
+	int irq;
+	unsigned long id;
+	uint8_t mode;
+};
+
+static int __adp5520_read(struct i2c_client *client,
+				int reg, uint8_t *val)
+{
+	int ret;
+
+	ret = i2c_smbus_read_byte_data(client, reg);
+	if (ret < 0) {
+		dev_err(&client->dev, "failed reading at 0x%02x\n", reg);
+		return ret;
+	}
+
+	*val = (uint8_t)ret;
+	return 0;
+}
+
+static int __adp5520_write(struct i2c_client *client,
+				 int reg, uint8_t val)
+{
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(client, reg, val);
+	if (ret < 0) {
+		dev_err(&client->dev, "failed writing 0x%02x to 0x%02x\n",
+				val, reg);
+		return ret;
+	}
+	return 0;
+}
+
+static int __adp5520_ack_bits(struct i2c_client *client, int reg,
+			      uint8_t bit_mask)
+{
+	struct adp5520_chip *chip = i2c_get_clientdata(client);
+	uint8_t reg_val;
+	int ret;
+
+	mutex_lock(&chip->lock);
+
+	ret = __adp5520_read(client, reg, &reg_val);
+
+	if (!ret) {
+		reg_val |= bit_mask;
+		ret = __adp5520_write(client, reg, reg_val);
+	}
+
+	mutex_unlock(&chip->lock);
+	return ret;
+}
+
+int adp5520_write(struct device *dev, int reg, uint8_t val)
+{
+	return __adp5520_write(to_i2c_client(dev), reg, val);
+}
+EXPORT_SYMBOL_GPL(adp5520_write);
+
+int adp5520_read(struct device *dev, int reg, uint8_t *val)
+{
+	return __adp5520_read(to_i2c_client(dev), reg, val);
+}
+EXPORT_SYMBOL_GPL(adp5520_read);
+
+int adp5520_set_bits(struct device *dev, int reg, uint8_t bit_mask)
+{
+	struct adp5520_chip *chip = dev_get_drvdata(dev);
+	uint8_t reg_val;
+	int ret;
+
+	mutex_lock(&chip->lock);
+
+	ret = __adp5520_read(chip->client, reg, &reg_val);
+
+	if (!ret && ((reg_val & bit_mask) != bit_mask)) {
+		reg_val |= bit_mask;
+		ret = __adp5520_write(chip->client, reg, reg_val);
+	}
+
+	mutex_unlock(&chip->lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(adp5520_set_bits);
+
+int adp5520_clr_bits(struct device *dev, int reg, uint8_t bit_mask)
+{
+	struct adp5520_chip *chip = dev_get_drvdata(dev);
+	uint8_t reg_val;
+	int ret;
+
+	mutex_lock(&chip->lock);
+
+	ret = __adp5520_read(chip->client, reg, &reg_val);
+
+	if (!ret && (reg_val & bit_mask)) {
+		reg_val &= ~bit_mask;
+		ret = __adp5520_write(chip->client, reg, reg_val);
+	}
+
+	mutex_unlock(&chip->lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(adp5520_clr_bits);
+
+int adp5520_register_notifier(struct device *dev, struct notifier_block *nb,
+				unsigned int events)
+{
+	struct adp5520_chip *chip = dev_get_drvdata(dev);
+
+	if (chip->irq) {
+		adp5520_set_bits(chip->dev, ADP5520_INTERRUPT_ENABLE,
+			events & (ADP5520_KP_IEN | ADP5520_KR_IEN |
+			ADP5520_OVP_IEN | ADP5520_CMPR_IEN));
+
+		return blocking_notifier_chain_register(&chip->notifier_list,
+			 nb);
+	}
+
+	return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(adp5520_register_notifier);
+
+int adp5520_unregister_notifier(struct device *dev, struct notifier_block *nb,
+				unsigned int events)
+{
+	struct adp5520_chip *chip = dev_get_drvdata(dev);
+
+	adp5520_clr_bits(chip->dev, ADP5520_INTERRUPT_ENABLE,
+		events & (ADP5520_KP_IEN | ADP5520_KR_IEN |
+		ADP5520_OVP_IEN | ADP5520_CMPR_IEN));
+
+	return blocking_notifier_chain_unregister(&chip->notifier_list, nb);
+}
+EXPORT_SYMBOL_GPL(adp5520_unregister_notifier);
+
+static irqreturn_t adp5520_irq_thread(int irq, void *data)
+{
+	struct adp5520_chip *chip = data;
+	unsigned int events;
+	uint8_t reg_val;
+	int ret;
+
+	ret = __adp5520_read(chip->client, ADP5520_MODE_STATUS, &reg_val);
+	if (ret)
+		goto out;
+
+	events =  reg_val & (ADP5520_OVP_INT | ADP5520_CMPR_INT |
+		ADP5520_GPI_INT | ADP5520_KR_INT | ADP5520_KP_INT);
+
+	blocking_notifier_call_chain(&chip->notifier_list, events, NULL);
+	/* ACK, Sticky bits are W1C */
+	__adp5520_ack_bits(chip->client, ADP5520_MODE_STATUS, events);
+
+out:
+	return IRQ_HANDLED;
+}
+
+static int __remove_subdev(struct device *dev, void *unused)
+{
+	platform_device_unregister(to_platform_device(dev));
+	return 0;
+}
+
+static int adp5520_remove_subdevs(struct adp5520_chip *chip)
+{
+	return device_for_each_child(chip->dev, NULL, __remove_subdev);
+}
+
+static int adp5520_probe(struct i2c_client *client)
+{
+	const struct i2c_device_id *id = i2c_client_get_device_id(client);
+	struct adp5520_platform_data *pdata = dev_get_platdata(&client->dev);
+	struct platform_device *pdev;
+	struct adp5520_chip *chip;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter,
+					I2C_FUNC_SMBUS_BYTE_DATA)) {
+		dev_err(&client->dev, "SMBUS Word Data not Supported\n");
+		return -EIO;
+	}
+
+	if (pdata == NULL) {
+		dev_err(&client->dev, "missing platform data\n");
+		return -ENODEV;
+	}
+
+	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, chip);
+	chip->client = client;
+
+	chip->dev = &client->dev;
+	chip->irq = client->irq;
+	chip->id = id->driver_data;
+	mutex_init(&chip->lock);
+
+	if (chip->irq) {
+		BLOCKING_INIT_NOTIFIER_HEAD(&chip->notifier_list);
+
+		ret = request_threaded_irq(chip->irq, NULL, adp5520_irq_thread,
+				IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+				"adp5520", chip);
+		if (ret) {
+			dev_err(&client->dev, "failed to request irq %d\n",
+					chip->irq);
+			return ret;
+		}
+	}
+
+	ret = adp5520_write(chip->dev, ADP5520_MODE_STATUS, ADP5520_nSTNBY);
+	if (ret) {
+		dev_err(&client->dev, "failed to write\n");
+		goto out_free_irq;
+	}
+
+	if (pdata->keys) {
+		pdev = platform_device_register_data(chip->dev, "adp5520-keys",
+				chip->id, pdata->keys, sizeof(*pdata->keys));
+		if (IS_ERR(pdev)) {
+			ret = PTR_ERR(pdev);
+			goto out_remove_subdevs;
+		}
+	}
+
+	if (pdata->gpio) {
+		pdev = platform_device_register_data(chip->dev, "adp5520-gpio",
+				chip->id, pdata->gpio, sizeof(*pdata->gpio));
+		if (IS_ERR(pdev)) {
+			ret = PTR_ERR(pdev);
+			goto out_remove_subdevs;
+		}
+	}
+
+	if (pdata->leds) {
+		pdev = platform_device_register_data(chip->dev, "adp5520-led",
+				chip->id, pdata->leds, sizeof(*pdata->leds));
+		if (IS_ERR(pdev)) {
+			ret = PTR_ERR(pdev);
+			goto out_remove_subdevs;
+		}
+	}
+
+	if (pdata->backlight) {
+		pdev = platform_device_register_data(chip->dev,
+						"adp5520-backlight",
+						chip->id,
+						pdata->backlight,
+						sizeof(*pdata->backlight));
+		if (IS_ERR(pdev)) {
+			ret = PTR_ERR(pdev);
+			goto out_remove_subdevs;
+		}
+	}
+
+	return 0;
+
+out_remove_subdevs:
+	adp5520_remove_subdevs(chip);
+
+out_free_irq:
+	if (chip->irq)
+		free_irq(chip->irq, chip);
+
+	return ret;
+}
+
+static int adp5520_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct adp5520_chip *chip = dev_get_drvdata(&client->dev);
+
+	adp5520_read(chip->dev, ADP5520_MODE_STATUS, &chip->mode);
+	/* All other bits are W1C */
+	chip->mode &= ADP5520_BL_EN | ADP5520_DIM_EN | ADP5520_nSTNBY;
+	adp5520_write(chip->dev, ADP5520_MODE_STATUS, 0);
+	return 0;
+}
+
+static int adp5520_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct adp5520_chip *chip = dev_get_drvdata(&client->dev);
+
+	adp5520_write(chip->dev, ADP5520_MODE_STATUS, chip->mode);
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(adp5520_pm, adp5520_suspend, adp5520_resume);
+
+static const struct i2c_device_id adp5520_id[] = {
+	{ "pmic-adp5520", ID_ADP5520 },
+	{ "pmic-adp5501", ID_ADP5501 },
+	{ }
+};
+
+static struct i2c_driver adp5520_driver = {
+	.driver = {
+		.name			= "adp5520",
+		.pm			= pm_sleep_ptr(&adp5520_pm),
+		.suppress_bind_attrs	= true,
+	},
+	.probe		= adp5520_probe,
+	.id_table	= adp5520_id,
+};
+builtin_i2c_driver(adp5520_driver);