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, 211 insertions, 0 deletions

diff --git a/drivers/input/misc/arizona-haptics.c b/drivers/input/misc/arizona-haptics.c
new file mode 100644
index 000000000..bb1544d63
--- /dev/null
+++ b/drivers/input/misc/arizona-haptics.c
@@ -0,0 +1,211 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Arizona haptics driver
+ *
+ * Copyright 2012 Wolfson Microelectronics plc
+ *
+ * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/input.h>
+#include <linux/slab.h>
+
+#include <sound/soc.h>
+#include <sound/soc-dapm.h>
+
+#include <linux/mfd/arizona/core.h>
+#include <linux/mfd/arizona/pdata.h>
+#include <linux/mfd/arizona/registers.h>
+
+struct arizona_haptics {
+	struct arizona *arizona;
+	struct input_dev *input_dev;
+	struct work_struct work;
+
+	struct mutex mutex;
+	u8 intensity;
+};
+
+static void arizona_haptics_work(struct work_struct *work)
+{
+	struct arizona_haptics *haptics = container_of(work,
+						       struct arizona_haptics,
+						       work);
+	struct arizona *arizona = haptics->arizona;
+	int ret;
+
+	if (!haptics->arizona->dapm) {
+		dev_err(arizona->dev, "No DAPM context\n");
+		return;
+	}
+
+	if (haptics->intensity) {
+		ret = regmap_update_bits(arizona->regmap,
+					 ARIZONA_HAPTICS_PHASE_2_INTENSITY,
+					 ARIZONA_PHASE2_INTENSITY_MASK,
+					 haptics->intensity);
+		if (ret != 0) {
+			dev_err(arizona->dev, "Failed to set intensity: %d\n",
+				ret);
+			return;
+		}
+
+		/* This enable sequence will be a noop if already enabled */
+		ret = regmap_update_bits(arizona->regmap,
+					 ARIZONA_HAPTICS_CONTROL_1,
+					 ARIZONA_HAP_CTRL_MASK,
+					 1 << ARIZONA_HAP_CTRL_SHIFT);
+		if (ret != 0) {
+			dev_err(arizona->dev, "Failed to start haptics: %d\n",
+				ret);
+			return;
+		}
+
+		ret = snd_soc_dapm_enable_pin(arizona->dapm, "HAPTICS");
+		if (ret != 0) {
+			dev_err(arizona->dev, "Failed to start HAPTICS: %d\n",
+				ret);
+			return;
+		}
+
+		ret = snd_soc_dapm_sync(arizona->dapm);
+		if (ret != 0) {
+			dev_err(arizona->dev, "Failed to sync DAPM: %d\n",
+				ret);
+			return;
+		}
+	} else {
+		/* This disable sequence will be a noop if already enabled */
+		ret = snd_soc_dapm_disable_pin(arizona->dapm, "HAPTICS");
+		if (ret != 0) {
+			dev_err(arizona->dev, "Failed to disable HAPTICS: %d\n",
+				ret);
+			return;
+		}
+
+		ret = snd_soc_dapm_sync(arizona->dapm);
+		if (ret != 0) {
+			dev_err(arizona->dev, "Failed to sync DAPM: %d\n",
+				ret);
+			return;
+		}
+
+		ret = regmap_update_bits(arizona->regmap,
+					 ARIZONA_HAPTICS_CONTROL_1,
+					 ARIZONA_HAP_CTRL_MASK, 0);
+		if (ret != 0) {
+			dev_err(arizona->dev, "Failed to stop haptics: %d\n",
+				ret);
+			return;
+		}
+	}
+}
+
+static int arizona_haptics_play(struct input_dev *input, void *data,
+				struct ff_effect *effect)
+{
+	struct arizona_haptics *haptics = input_get_drvdata(input);
+	struct arizona *arizona = haptics->arizona;
+
+	if (!arizona->dapm) {
+		dev_err(arizona->dev, "No DAPM context\n");
+		return -EBUSY;
+	}
+
+	if (effect->u.rumble.strong_magnitude) {
+		/* Scale the magnitude into the range the device supports */
+		if (arizona->pdata.hap_act) {
+			haptics->intensity =
+				effect->u.rumble.strong_magnitude >> 9;
+			if (effect->direction < 0x8000)
+				haptics->intensity += 0x7f;
+		} else {
+			haptics->intensity =
+				effect->u.rumble.strong_magnitude >> 8;
+		}
+	} else {
+		haptics->intensity = 0;
+	}
+
+	schedule_work(&haptics->work);
+
+	return 0;
+}
+
+static void arizona_haptics_close(struct input_dev *input)
+{
+	struct arizona_haptics *haptics = input_get_drvdata(input);
+	struct snd_soc_dapm_context *dapm = haptics->arizona->dapm;
+
+	cancel_work_sync(&haptics->work);
+
+	if (dapm)
+		snd_soc_dapm_disable_pin(dapm, "HAPTICS");
+}
+
+static int arizona_haptics_probe(struct platform_device *pdev)
+{
+	struct arizona *arizona = dev_get_drvdata(pdev->dev.parent);
+	struct arizona_haptics *haptics;
+	int ret;
+
+	haptics = devm_kzalloc(&pdev->dev, sizeof(*haptics), GFP_KERNEL);
+	if (!haptics)
+		return -ENOMEM;
+
+	haptics->arizona = arizona;
+
+	ret = regmap_update_bits(arizona->regmap, ARIZONA_HAPTICS_CONTROL_1,
+				 ARIZONA_HAP_ACT, arizona->pdata.hap_act);
+	if (ret != 0) {
+		dev_err(arizona->dev, "Failed to set haptics actuator: %d\n",
+			ret);
+		return ret;
+	}
+
+	INIT_WORK(&haptics->work, arizona_haptics_work);
+
+	haptics->input_dev = devm_input_allocate_device(&pdev->dev);
+	if (!haptics->input_dev) {
+		dev_err(arizona->dev, "Failed to allocate input device\n");
+		return -ENOMEM;
+	}
+
+	input_set_drvdata(haptics->input_dev, haptics);
+
+	haptics->input_dev->name = "arizona:haptics";
+	haptics->input_dev->close = arizona_haptics_close;
+	__set_bit(FF_RUMBLE, haptics->input_dev->ffbit);
+
+	ret = input_ff_create_memless(haptics->input_dev, NULL,
+				      arizona_haptics_play);
+	if (ret < 0) {
+		dev_err(arizona->dev, "input_ff_create_memless() failed: %d\n",
+			ret);
+		return ret;
+	}
+
+	ret = input_register_device(haptics->input_dev);
+	if (ret < 0) {
+		dev_err(arizona->dev, "couldn't register input device: %d\n",
+			ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static struct platform_driver arizona_haptics_driver = {
+	.probe		= arizona_haptics_probe,
+	.driver		= {
+		.name	= "arizona-haptics",
+	},
+};
+module_platform_driver(arizona_haptics_driver);
+
+MODULE_ALIAS("platform:arizona-haptics");
+MODULE_DESCRIPTION("Arizona haptics driver");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");