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, 368 insertions, 0 deletions

diff --git a/drivers/mfd/max77693.c b/drivers/mfd/max77693.c
new file mode 100644
index 000000000..1c485a4c3
--- /dev/null
+++ b/drivers/mfd/max77693.c
@@ -0,0 +1,368 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// max77693.c - mfd core driver for the MAX 77693
+//
+// Copyright (C) 2012 Samsung Electronics
+// SangYoung Son <hello.son@samsung.com>
+//
+// This program is not provided / owned by Maxim Integrated Products.
+//
+// This driver is based on max8997.c
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/of.h>
+#include <linux/pm_runtime.h>
+#include <linux/mutex.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/max77693.h>
+#include <linux/mfd/max77693-common.h>
+#include <linux/mfd/max77693-private.h>
+#include <linux/regulator/machine.h>
+#include <linux/regmap.h>
+
+#define I2C_ADDR_PMIC	(0xCC >> 1)	/* Charger, Flash LED */
+#define I2C_ADDR_MUIC	(0x4A >> 1)
+#define I2C_ADDR_HAPTIC	(0x90 >> 1)
+
+static const struct mfd_cell max77693_devs[] = {
+	{ .name = "max77693-pmic", },
+	{
+		.name = "max77693-charger",
+		.of_compatible = "maxim,max77693-charger",
+	},
+	{
+		.name = "max77693-muic",
+		.of_compatible = "maxim,max77693-muic",
+	},
+	{
+		.name = "max77693-haptic",
+		.of_compatible = "maxim,max77693-haptic",
+	},
+	{
+		.name = "max77693-led",
+		.of_compatible = "maxim,max77693-led",
+	},
+};
+
+static const struct regmap_config max77693_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = MAX77693_PMIC_REG_END,
+};
+
+static const struct regmap_irq max77693_led_irqs[] = {
+	{ .mask = LED_IRQ_FLED2_OPEN,  },
+	{ .mask = LED_IRQ_FLED2_SHORT, },
+	{ .mask = LED_IRQ_FLED1_OPEN,  },
+	{ .mask = LED_IRQ_FLED1_SHORT, },
+	{ .mask = LED_IRQ_MAX_FLASH,   },
+};
+
+static const struct regmap_irq_chip max77693_led_irq_chip = {
+	.name			= "max77693-led",
+	.status_base		= MAX77693_LED_REG_FLASH_INT,
+	.mask_base		= MAX77693_LED_REG_FLASH_INT_MASK,
+	.num_regs		= 1,
+	.irqs			= max77693_led_irqs,
+	.num_irqs		= ARRAY_SIZE(max77693_led_irqs),
+};
+
+static const struct regmap_irq max77693_topsys_irqs[] = {
+	{ .mask = TOPSYS_IRQ_T120C_INT,  },
+	{ .mask = TOPSYS_IRQ_T140C_INT,  },
+	{ .mask = TOPSYS_IRQ_LOWSYS_INT, },
+};
+
+static const struct regmap_irq_chip max77693_topsys_irq_chip = {
+	.name			= "max77693-topsys",
+	.status_base		= MAX77693_PMIC_REG_TOPSYS_INT,
+	.mask_base		= MAX77693_PMIC_REG_TOPSYS_INT_MASK,
+	.num_regs		= 1,
+	.irqs			= max77693_topsys_irqs,
+	.num_irqs		= ARRAY_SIZE(max77693_topsys_irqs),
+};
+
+static const struct regmap_irq max77693_charger_irqs[] = {
+	{ .mask = CHG_IRQ_BYP_I,   },
+	{ .mask = CHG_IRQ_THM_I,   },
+	{ .mask = CHG_IRQ_BAT_I,   },
+	{ .mask = CHG_IRQ_CHG_I,   },
+	{ .mask = CHG_IRQ_CHGIN_I, },
+};
+
+static const struct regmap_irq_chip max77693_charger_irq_chip = {
+	.name			= "max77693-charger",
+	.status_base		= MAX77693_CHG_REG_CHG_INT,
+	.mask_base		= MAX77693_CHG_REG_CHG_INT_MASK,
+	.num_regs		= 1,
+	.irqs			= max77693_charger_irqs,
+	.num_irqs		= ARRAY_SIZE(max77693_charger_irqs),
+};
+
+static const struct regmap_config max77693_regmap_muic_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = MAX77693_MUIC_REG_END,
+};
+
+static const struct regmap_irq max77693_muic_irqs[] = {
+	{ .reg_offset = 0, .mask = MUIC_IRQ_INT1_ADC,		},
+	{ .reg_offset = 0, .mask = MUIC_IRQ_INT1_ADC_LOW,	},
+	{ .reg_offset = 0, .mask = MUIC_IRQ_INT1_ADC_ERR,	},
+	{ .reg_offset = 0, .mask = MUIC_IRQ_INT1_ADC1K,		},
+
+	{ .reg_offset = 1, .mask = MUIC_IRQ_INT2_CHGTYP,	},
+	{ .reg_offset = 1, .mask = MUIC_IRQ_INT2_CHGDETREUN,	},
+	{ .reg_offset = 1, .mask = MUIC_IRQ_INT2_DCDTMR,	},
+	{ .reg_offset = 1, .mask = MUIC_IRQ_INT2_DXOVP,		},
+	{ .reg_offset = 1, .mask = MUIC_IRQ_INT2_VBVOLT,	},
+	{ .reg_offset = 1, .mask = MUIC_IRQ_INT2_VIDRM,		},
+
+	{ .reg_offset = 2, .mask = MUIC_IRQ_INT3_EOC,		},
+	{ .reg_offset = 2, .mask = MUIC_IRQ_INT3_CGMBC,		},
+	{ .reg_offset = 2, .mask = MUIC_IRQ_INT3_OVP,		},
+	{ .reg_offset = 2, .mask = MUIC_IRQ_INT3_MBCCHG_ERR,	},
+	{ .reg_offset = 2, .mask = MUIC_IRQ_INT3_CHG_ENABLED,	},
+	{ .reg_offset = 2, .mask = MUIC_IRQ_INT3_BAT_DET,	},
+};
+
+static const struct regmap_irq_chip max77693_muic_irq_chip = {
+	.name			= "max77693-muic",
+	.status_base		= MAX77693_MUIC_REG_INT1,
+	.unmask_base		= MAX77693_MUIC_REG_INTMASK1,
+	.num_regs		= 3,
+	.irqs			= max77693_muic_irqs,
+	.num_irqs		= ARRAY_SIZE(max77693_muic_irqs),
+};
+
+static const struct regmap_config max77693_regmap_haptic_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = MAX77693_HAPTIC_REG_END,
+};
+
+static int max77693_i2c_probe(struct i2c_client *i2c)
+{
+	const struct i2c_device_id *id = i2c_client_get_device_id(i2c);
+	struct max77693_dev *max77693;
+	unsigned int reg_data;
+	int ret = 0;
+
+	max77693 = devm_kzalloc(&i2c->dev,
+			sizeof(struct max77693_dev), GFP_KERNEL);
+	if (max77693 == NULL)
+		return -ENOMEM;
+
+	i2c_set_clientdata(i2c, max77693);
+	max77693->dev = &i2c->dev;
+	max77693->i2c = i2c;
+	max77693->irq = i2c->irq;
+	max77693->type = id->driver_data;
+
+	max77693->regmap = devm_regmap_init_i2c(i2c, &max77693_regmap_config);
+	if (IS_ERR(max77693->regmap)) {
+		ret = PTR_ERR(max77693->regmap);
+		dev_err(max77693->dev, "failed to allocate register map: %d\n",
+				ret);
+		return ret;
+	}
+
+	ret = regmap_read(max77693->regmap, MAX77693_PMIC_REG_PMIC_ID2,
+				&reg_data);
+	if (ret < 0) {
+		dev_err(max77693->dev, "device not found on this channel\n");
+		return ret;
+	} else
+		dev_info(max77693->dev, "device ID: 0x%x\n", reg_data);
+
+	max77693->i2c_muic = i2c_new_dummy_device(i2c->adapter, I2C_ADDR_MUIC);
+	if (IS_ERR(max77693->i2c_muic)) {
+		dev_err(max77693->dev, "Failed to allocate I2C device for MUIC\n");
+		return PTR_ERR(max77693->i2c_muic);
+	}
+	i2c_set_clientdata(max77693->i2c_muic, max77693);
+
+	max77693->i2c_haptic = i2c_new_dummy_device(i2c->adapter, I2C_ADDR_HAPTIC);
+	if (IS_ERR(max77693->i2c_haptic)) {
+		dev_err(max77693->dev, "Failed to allocate I2C device for Haptic\n");
+		ret = PTR_ERR(max77693->i2c_haptic);
+		goto err_i2c_haptic;
+	}
+	i2c_set_clientdata(max77693->i2c_haptic, max77693);
+
+	max77693->regmap_haptic = devm_regmap_init_i2c(max77693->i2c_haptic,
+					&max77693_regmap_haptic_config);
+	if (IS_ERR(max77693->regmap_haptic)) {
+		ret = PTR_ERR(max77693->regmap_haptic);
+		dev_err(max77693->dev,
+			"failed to initialize haptic register map: %d\n", ret);
+		goto err_regmap;
+	}
+
+	/*
+	 * Initialize register map for MUIC device because use regmap-muic
+	 * instance of MUIC device when irq of max77693 is initialized
+	 * before call max77693-muic probe() function.
+	 */
+	max77693->regmap_muic = devm_regmap_init_i2c(max77693->i2c_muic,
+					 &max77693_regmap_muic_config);
+	if (IS_ERR(max77693->regmap_muic)) {
+		ret = PTR_ERR(max77693->regmap_muic);
+		dev_err(max77693->dev,
+			"failed to allocate register map: %d\n", ret);
+		goto err_regmap;
+	}
+
+	ret = regmap_add_irq_chip(max77693->regmap, max77693->irq,
+				IRQF_ONESHOT | IRQF_SHARED, 0,
+				&max77693_led_irq_chip,
+				&max77693->irq_data_led);
+	if (ret) {
+		dev_err(max77693->dev, "failed to add irq chip: %d\n", ret);
+		goto err_regmap;
+	}
+
+	ret = regmap_add_irq_chip(max77693->regmap, max77693->irq,
+				IRQF_ONESHOT | IRQF_SHARED, 0,
+				&max77693_topsys_irq_chip,
+				&max77693->irq_data_topsys);
+	if (ret) {
+		dev_err(max77693->dev, "failed to add irq chip: %d\n", ret);
+		goto err_irq_topsys;
+	}
+
+	ret = regmap_add_irq_chip(max77693->regmap, max77693->irq,
+				IRQF_ONESHOT | IRQF_SHARED, 0,
+				&max77693_charger_irq_chip,
+				&max77693->irq_data_chg);
+	if (ret) {
+		dev_err(max77693->dev, "failed to add irq chip: %d\n", ret);
+		goto err_irq_charger;
+	}
+
+	ret = regmap_add_irq_chip(max77693->regmap_muic, max77693->irq,
+				IRQF_ONESHOT | IRQF_SHARED, 0,
+				&max77693_muic_irq_chip,
+				&max77693->irq_data_muic);
+	if (ret) {
+		dev_err(max77693->dev, "failed to add irq chip: %d\n", ret);
+		goto err_irq_muic;
+	}
+
+	/* Unmask interrupts from all blocks in interrupt source register */
+	ret = regmap_update_bits(max77693->regmap,
+				MAX77693_PMIC_REG_INTSRC_MASK,
+				SRC_IRQ_ALL, (unsigned int)~SRC_IRQ_ALL);
+	if (ret < 0) {
+		dev_err(max77693->dev,
+			"Could not unmask interrupts in INTSRC: %d\n",
+			ret);
+		goto err_intsrc;
+	}
+
+	pm_runtime_set_active(max77693->dev);
+
+	ret = mfd_add_devices(max77693->dev, -1, max77693_devs,
+			      ARRAY_SIZE(max77693_devs), NULL, 0, NULL);
+	if (ret < 0)
+		goto err_mfd;
+
+	return ret;
+
+err_mfd:
+	mfd_remove_devices(max77693->dev);
+err_intsrc:
+	regmap_del_irq_chip(max77693->irq, max77693->irq_data_muic);
+err_irq_muic:
+	regmap_del_irq_chip(max77693->irq, max77693->irq_data_chg);
+err_irq_charger:
+	regmap_del_irq_chip(max77693->irq, max77693->irq_data_topsys);
+err_irq_topsys:
+	regmap_del_irq_chip(max77693->irq, max77693->irq_data_led);
+err_regmap:
+	i2c_unregister_device(max77693->i2c_haptic);
+err_i2c_haptic:
+	i2c_unregister_device(max77693->i2c_muic);
+	return ret;
+}
+
+static void max77693_i2c_remove(struct i2c_client *i2c)
+{
+	struct max77693_dev *max77693 = i2c_get_clientdata(i2c);
+
+	mfd_remove_devices(max77693->dev);
+
+	regmap_del_irq_chip(max77693->irq, max77693->irq_data_muic);
+	regmap_del_irq_chip(max77693->irq, max77693->irq_data_chg);
+	regmap_del_irq_chip(max77693->irq, max77693->irq_data_topsys);
+	regmap_del_irq_chip(max77693->irq, max77693->irq_data_led);
+
+	i2c_unregister_device(max77693->i2c_muic);
+	i2c_unregister_device(max77693->i2c_haptic);
+}
+
+static const struct i2c_device_id max77693_i2c_id[] = {
+	{ "max77693", TYPE_MAX77693 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, max77693_i2c_id);
+
+static int max77693_suspend(struct device *dev)
+{
+	struct i2c_client *i2c = to_i2c_client(dev);
+	struct max77693_dev *max77693 = i2c_get_clientdata(i2c);
+
+	if (device_may_wakeup(dev)) {
+		enable_irq_wake(max77693->irq);
+		disable_irq(max77693->irq);
+	}
+
+	return 0;
+}
+
+static int max77693_resume(struct device *dev)
+{
+	struct i2c_client *i2c = to_i2c_client(dev);
+	struct max77693_dev *max77693 = i2c_get_clientdata(i2c);
+
+	if (device_may_wakeup(dev)) {
+		disable_irq_wake(max77693->irq);
+		enable_irq(max77693->irq);
+	}
+
+	return 0;
+}
+
+static const struct dev_pm_ops max77693_pm = {
+	.suspend = max77693_suspend,
+	.resume = max77693_resume,
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id max77693_dt_match[] = {
+	{ .compatible = "maxim,max77693" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, max77693_dt_match);
+#endif
+
+static struct i2c_driver max77693_i2c_driver = {
+	.driver = {
+		   .name = "max77693",
+		   .pm = &max77693_pm,
+		   .of_match_table = of_match_ptr(max77693_dt_match),
+	},
+	.probe = max77693_i2c_probe,
+	.remove = max77693_i2c_remove,
+	.id_table = max77693_i2c_id,
+};
+
+module_i2c_driver(max77693_i2c_driver);
+
+MODULE_DESCRIPTION("MAXIM 77693 multi-function core driver");
+MODULE_AUTHOR("SangYoung, Son <hello.son@samsung.com>");
+MODULE_LICENSE("GPL");