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, 218 insertions, 0 deletions

diff --git a/drivers/extcon/extcon-qcom-spmi-misc.c b/drivers/extcon/extcon-qcom-spmi-misc.c
new file mode 100644
index 000000000..3c522c9c9
--- /dev/null
+++ b/drivers/extcon/extcon-qcom-spmi-misc.c
@@ -0,0 +1,218 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * extcon-qcom-spmi-misc.c - Qualcomm USB extcon driver to support USB ID
+ *			and VBUS detection based on extcon-usb-gpio.c.
+ *
+ * Copyright (C) 2016 Linaro, Ltd.
+ * Stephen Boyd <stephen.boyd@linaro.org>
+ */
+
+#include <linux/devm-helpers.h>
+#include <linux/extcon-provider.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+#define USB_ID_DEBOUNCE_MS	5	/* ms */
+
+struct qcom_usb_extcon_info {
+	struct extcon_dev *edev;
+	int id_irq;
+	int vbus_irq;
+	struct delayed_work wq_detcable;
+	unsigned long debounce_jiffies;
+};
+
+static const unsigned int qcom_usb_extcon_cable[] = {
+	EXTCON_USB,
+	EXTCON_USB_HOST,
+	EXTCON_NONE,
+};
+
+static void qcom_usb_extcon_detect_cable(struct work_struct *work)
+{
+	bool state = false;
+	int ret;
+	union extcon_property_value val;
+	struct qcom_usb_extcon_info *info = container_of(to_delayed_work(work),
+						    struct qcom_usb_extcon_info,
+						    wq_detcable);
+
+	if (info->id_irq > 0) {
+		/* check ID and update cable state */
+		ret = irq_get_irqchip_state(info->id_irq,
+				IRQCHIP_STATE_LINE_LEVEL, &state);
+		if (ret)
+			return;
+
+		if (!state) {
+			val.intval = true;
+			extcon_set_property(info->edev, EXTCON_USB_HOST,
+						EXTCON_PROP_USB_SS, val);
+		}
+		extcon_set_state_sync(info->edev, EXTCON_USB_HOST, !state);
+	}
+
+	if (info->vbus_irq > 0) {
+		/* check VBUS and update cable state */
+		ret = irq_get_irqchip_state(info->vbus_irq,
+				IRQCHIP_STATE_LINE_LEVEL, &state);
+		if (ret)
+			return;
+
+		if (state) {
+			val.intval = true;
+			extcon_set_property(info->edev, EXTCON_USB,
+						EXTCON_PROP_USB_SS, val);
+		}
+		extcon_set_state_sync(info->edev, EXTCON_USB, state);
+	}
+}
+
+static irqreturn_t qcom_usb_irq_handler(int irq, void *dev_id)
+{
+	struct qcom_usb_extcon_info *info = dev_id;
+
+	queue_delayed_work(system_power_efficient_wq, &info->wq_detcable,
+			   info->debounce_jiffies);
+
+	return IRQ_HANDLED;
+}
+
+static int qcom_usb_extcon_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct qcom_usb_extcon_info *info;
+	int ret;
+
+	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->edev = devm_extcon_dev_allocate(dev, qcom_usb_extcon_cable);
+	if (IS_ERR(info->edev)) {
+		dev_err(dev, "failed to allocate extcon device\n");
+		return -ENOMEM;
+	}
+
+	ret = devm_extcon_dev_register(dev, info->edev);
+	if (ret < 0) {
+		dev_err(dev, "failed to register extcon device\n");
+		return ret;
+	}
+
+	ret = extcon_set_property_capability(info->edev,
+			EXTCON_USB, EXTCON_PROP_USB_SS);
+	ret |= extcon_set_property_capability(info->edev,
+			EXTCON_USB_HOST, EXTCON_PROP_USB_SS);
+	if (ret) {
+		dev_err(dev, "failed to register extcon props rc=%d\n",
+						ret);
+		return ret;
+	}
+
+	info->debounce_jiffies = msecs_to_jiffies(USB_ID_DEBOUNCE_MS);
+
+	ret = devm_delayed_work_autocancel(dev, &info->wq_detcable,
+					   qcom_usb_extcon_detect_cable);
+	if (ret)
+		return ret;
+
+	info->id_irq = platform_get_irq_byname_optional(pdev, "usb_id");
+	if (info->id_irq > 0) {
+		ret = devm_request_threaded_irq(dev, info->id_irq, NULL,
+					qcom_usb_irq_handler,
+					IRQF_TRIGGER_RISING |
+					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+					pdev->name, info);
+		if (ret < 0) {
+			dev_err(dev, "failed to request handler for ID IRQ\n");
+			return ret;
+		}
+	}
+
+	info->vbus_irq = platform_get_irq_byname_optional(pdev, "usb_vbus");
+	if (info->vbus_irq > 0) {
+		ret = devm_request_threaded_irq(dev, info->vbus_irq, NULL,
+					qcom_usb_irq_handler,
+					IRQF_TRIGGER_RISING |
+					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+					pdev->name, info);
+		if (ret < 0) {
+			dev_err(dev, "failed to request handler for VBUS IRQ\n");
+			return ret;
+		}
+	}
+
+	if (info->id_irq < 0 && info->vbus_irq < 0) {
+		dev_err(dev, "ID and VBUS IRQ not found\n");
+		return -EINVAL;
+	}
+
+	platform_set_drvdata(pdev, info);
+	devm_device_init_wakeup(dev);
+
+	/* Perform initial detection */
+	qcom_usb_extcon_detect_cable(&info->wq_detcable.work);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int qcom_usb_extcon_suspend(struct device *dev)
+{
+	struct qcom_usb_extcon_info *info = dev_get_drvdata(dev);
+	int ret = 0;
+
+	if (device_may_wakeup(dev)) {
+		if (info->id_irq > 0)
+			ret = enable_irq_wake(info->id_irq);
+		if (info->vbus_irq > 0)
+			ret = enable_irq_wake(info->vbus_irq);
+	}
+
+	return ret;
+}
+
+static int qcom_usb_extcon_resume(struct device *dev)
+{
+	struct qcom_usb_extcon_info *info = dev_get_drvdata(dev);
+	int ret = 0;
+
+	if (device_may_wakeup(dev)) {
+		if (info->id_irq > 0)
+			ret = disable_irq_wake(info->id_irq);
+		if (info->vbus_irq > 0)
+			ret = disable_irq_wake(info->vbus_irq);
+	}
+
+	return ret;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(qcom_usb_extcon_pm_ops,
+			 qcom_usb_extcon_suspend, qcom_usb_extcon_resume);
+
+static const struct of_device_id qcom_usb_extcon_dt_match[] = {
+	{ .compatible = "qcom,pm8941-misc", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, qcom_usb_extcon_dt_match);
+
+static struct platform_driver qcom_usb_extcon_driver = {
+	.probe		= qcom_usb_extcon_probe,
+	.driver		= {
+		.name	= "extcon-pm8941-misc",
+		.pm	= &qcom_usb_extcon_pm_ops,
+		.of_match_table = qcom_usb_extcon_dt_match,
+	},
+};
+module_platform_driver(qcom_usb_extcon_driver);
+
+MODULE_DESCRIPTION("QCOM USB ID extcon driver");
+MODULE_AUTHOR("Stephen Boyd <stephen.boyd@linaro.org>");
+MODULE_LICENSE("GPL v2");