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, 208 insertions, 0 deletions

diff --git a/drivers/mfd/da9052-i2c.c b/drivers/mfd/da9052-i2c.c
new file mode 100644
index 000000000..fd000a21b
--- /dev/null
+++ b/drivers/mfd/da9052-i2c.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * I2C access for DA9052 PMICs.
+ *
+ * Copyright(c) 2011 Dialog Semiconductor Ltd.
+ *
+ * Author: David Dajun Chen <dchen@diasemi.com>
+ */
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/input.h>
+#include <linux/mfd/core.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/of.h>
+
+#include <linux/mfd/da9052/da9052.h>
+#include <linux/mfd/da9052/reg.h>
+
+
+/* I2C safe register check */
+static inline bool i2c_safe_reg(unsigned char reg)
+{
+	switch (reg) {
+	case DA9052_STATUS_A_REG:
+	case DA9052_STATUS_B_REG:
+	case DA9052_STATUS_C_REG:
+	case DA9052_STATUS_D_REG:
+	case DA9052_ADC_RES_L_REG:
+	case DA9052_ADC_RES_H_REG:
+	case DA9052_VDD_RES_REG:
+	case DA9052_ICHG_AV_REG:
+	case DA9052_TBAT_RES_REG:
+	case DA9052_ADCIN4_RES_REG:
+	case DA9052_ADCIN5_RES_REG:
+	case DA9052_ADCIN6_RES_REG:
+	case DA9052_TJUNC_RES_REG:
+	case DA9052_TSI_X_MSB_REG:
+	case DA9052_TSI_Y_MSB_REG:
+	case DA9052_TSI_LSB_REG:
+	case DA9052_TSI_Z_MSB_REG:
+		return true;
+	default:
+		return false;
+	}
+}
+
+/*
+ * There is an issue with DA9052 and DA9053_AA/BA/BB PMIC where the PMIC
+ * gets lockup up or fails to respond following a system reset.
+ * This fix is to follow any read or write with a dummy read to a safe
+ * register.
+ */
+static int da9052_i2c_fix(struct da9052 *da9052, unsigned char reg)
+{
+	int val;
+
+	switch (da9052->chip_id) {
+	case DA9052:
+	case DA9053_AA:
+	case DA9053_BA:
+	case DA9053_BB:
+		/* A dummy read to a safe register address. */
+		if (!i2c_safe_reg(reg))
+			return regmap_read(da9052->regmap,
+					   DA9052_PARK_REGISTER,
+					   &val);
+		break;
+	case DA9053_BC:
+	default:
+		/*
+		 * For other chips parking of I2C register
+		 * to a safe place is not required.
+		 */
+		break;
+	}
+
+	return 0;
+}
+
+/*
+ * According to errata item 24, multiwrite mode should be avoided
+ * in order to prevent register data corruption after power-down.
+ */
+static int da9052_i2c_disable_multiwrite(struct da9052 *da9052)
+{
+	int reg_val, ret;
+
+	ret = regmap_read(da9052->regmap, DA9052_CONTROL_B_REG, &reg_val);
+	if (ret < 0)
+		return ret;
+
+	if (!(reg_val & DA9052_CONTROL_B_WRITEMODE)) {
+		reg_val |= DA9052_CONTROL_B_WRITEMODE;
+		ret = regmap_write(da9052->regmap, DA9052_CONTROL_B_REG,
+				   reg_val);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static const struct i2c_device_id da9052_i2c_id[] = {
+	{"da9052", DA9052},
+	{"da9053-aa", DA9053_AA},
+	{"da9053-ba", DA9053_BA},
+	{"da9053-bb", DA9053_BB},
+	{"da9053-bc", DA9053_BC},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, da9052_i2c_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id dialog_dt_ids[] = {
+	{ .compatible = "dlg,da9052", .data = &da9052_i2c_id[0] },
+	{ .compatible = "dlg,da9053-aa", .data = &da9052_i2c_id[1] },
+	{ .compatible = "dlg,da9053-ba", .data = &da9052_i2c_id[2] },
+	{ .compatible = "dlg,da9053-bb", .data = &da9052_i2c_id[3] },
+	{ .compatible = "dlg,da9053-bc", .data = &da9052_i2c_id[4] },
+	{ /* sentinel */ }
+};
+#endif
+
+static int da9052_i2c_probe(struct i2c_client *client)
+{
+	const struct i2c_device_id *id = i2c_client_get_device_id(client);
+	struct da9052 *da9052;
+	int ret;
+
+	da9052 = devm_kzalloc(&client->dev, sizeof(struct da9052), GFP_KERNEL);
+	if (!da9052)
+		return -ENOMEM;
+
+	da9052->dev = &client->dev;
+	da9052->chip_irq = client->irq;
+	da9052->fix_io = da9052_i2c_fix;
+
+	i2c_set_clientdata(client, da9052);
+
+	da9052->regmap = devm_regmap_init_i2c(client, &da9052_regmap_config);
+	if (IS_ERR(da9052->regmap)) {
+		ret = PTR_ERR(da9052->regmap);
+		dev_err(&client->dev, "Failed to allocate register map: %d\n",
+			ret);
+		return ret;
+	}
+
+	ret = da9052_i2c_disable_multiwrite(da9052);
+	if (ret < 0)
+		return ret;
+
+#ifdef CONFIG_OF
+	if (!id)
+		id = of_device_get_match_data(&client->dev);
+#endif
+
+	if (!id) {
+		ret = -ENODEV;
+		dev_err(&client->dev, "id is null.\n");
+		return ret;
+	}
+
+	return da9052_device_init(da9052, id->driver_data);
+}
+
+static void da9052_i2c_remove(struct i2c_client *client)
+{
+	struct da9052 *da9052 = i2c_get_clientdata(client);
+
+	da9052_device_exit(da9052);
+}
+
+static struct i2c_driver da9052_i2c_driver = {
+	.probe = da9052_i2c_probe,
+	.remove = da9052_i2c_remove,
+	.id_table = da9052_i2c_id,
+	.driver = {
+		.name = "da9052",
+#ifdef CONFIG_OF
+		.of_match_table = dialog_dt_ids,
+#endif
+	},
+};
+
+static int __init da9052_i2c_init(void)
+{
+	int ret;
+
+	ret = i2c_add_driver(&da9052_i2c_driver);
+	if (ret != 0) {
+		pr_err("DA9052 I2C registration failed %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+subsys_initcall(da9052_i2c_init);
+
+static void __exit da9052_i2c_exit(void)
+{
+	i2c_del_driver(&da9052_i2c_driver);
+}
+module_exit(da9052_i2c_exit);
+
+MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
+MODULE_DESCRIPTION("I2C driver for Dialog DA9052 PMIC");