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, 287 insertions, 0 deletions

diff --git a/drivers/phy/qualcomm/phy-qcom-usb-hs.c b/drivers/phy/qualcomm/phy-qcom-usb-hs.c
new file mode 100644
index 000000000..928a982a8
--- /dev/null
+++ b/drivers/phy/qualcomm/phy-qcom-usb-hs.c
@@ -0,0 +1,287 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2016 Linaro Ltd
+ */
+#include <linux/module.h>
+#include <linux/ulpi/driver.h>
+#include <linux/ulpi/regs.h>
+#include <linux/clk.h>
+#include <linux/regulator/consumer.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/reset.h>
+#include <linux/extcon.h>
+#include <linux/notifier.h>
+
+#define ULPI_PWR_CLK_MNG_REG		0x88
+# define ULPI_PWR_OTG_COMP_DISABLE	BIT(0)
+
+#define ULPI_MISC_A			0x96
+# define ULPI_MISC_A_VBUSVLDEXTSEL	BIT(1)
+# define ULPI_MISC_A_VBUSVLDEXT		BIT(0)
+
+
+struct ulpi_seq {
+	u8 addr;
+	u8 val;
+};
+
+struct qcom_usb_hs_phy {
+	struct ulpi *ulpi;
+	struct phy *phy;
+	struct clk *ref_clk;
+	struct clk *sleep_clk;
+	struct regulator *v1p8;
+	struct regulator *v3p3;
+	struct reset_control *reset;
+	struct extcon_dev *vbus_edev;
+	struct notifier_block vbus_notify;
+	struct ulpi_seq init_seq[];
+};
+
+static int qcom_usb_hs_phy_set_mode(struct phy *phy,
+				    enum phy_mode mode, int submode)
+{
+	struct qcom_usb_hs_phy *uphy = phy_get_drvdata(phy);
+	u8 addr;
+	int ret;
+
+	if (!uphy->vbus_edev) {
+		u8 val = 0;
+
+		switch (mode) {
+		case PHY_MODE_USB_OTG:
+		case PHY_MODE_USB_HOST:
+			val |= ULPI_INT_IDGRD;
+			fallthrough;
+		case PHY_MODE_USB_DEVICE:
+			val |= ULPI_INT_SESS_VALID;
+			break;
+		default:
+			break;
+		}
+
+		ret = ulpi_write(uphy->ulpi, ULPI_USB_INT_EN_RISE, val);
+		if (ret)
+			return ret;
+		ret = ulpi_write(uphy->ulpi, ULPI_USB_INT_EN_FALL, val);
+	} else {
+		switch (mode) {
+		case PHY_MODE_USB_OTG:
+		case PHY_MODE_USB_DEVICE:
+			addr = ULPI_SET(ULPI_MISC_A);
+			break;
+		case PHY_MODE_USB_HOST:
+			addr = ULPI_CLR(ULPI_MISC_A);
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		ret = ulpi_write(uphy->ulpi, ULPI_SET(ULPI_PWR_CLK_MNG_REG),
+				 ULPI_PWR_OTG_COMP_DISABLE);
+		if (ret)
+			return ret;
+		ret = ulpi_write(uphy->ulpi, addr, ULPI_MISC_A_VBUSVLDEXTSEL);
+	}
+
+	return ret;
+}
+
+static int
+qcom_usb_hs_phy_vbus_notifier(struct notifier_block *nb, unsigned long event,
+			      void *ptr)
+{
+	struct qcom_usb_hs_phy *uphy;
+	u8 addr;
+
+	uphy = container_of(nb, struct qcom_usb_hs_phy, vbus_notify);
+
+	if (event)
+		addr = ULPI_SET(ULPI_MISC_A);
+	else
+		addr = ULPI_CLR(ULPI_MISC_A);
+
+	return ulpi_write(uphy->ulpi, addr, ULPI_MISC_A_VBUSVLDEXT);
+}
+
+static int qcom_usb_hs_phy_power_on(struct phy *phy)
+{
+	struct qcom_usb_hs_phy *uphy = phy_get_drvdata(phy);
+	struct ulpi *ulpi = uphy->ulpi;
+	const struct ulpi_seq *seq;
+	int ret, state;
+
+	ret = clk_prepare_enable(uphy->ref_clk);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(uphy->sleep_clk);
+	if (ret)
+		goto err_sleep;
+
+	ret = regulator_set_load(uphy->v1p8, 50000);
+	if (ret < 0)
+		goto err_1p8;
+
+	ret = regulator_enable(uphy->v1p8);
+	if (ret)
+		goto err_1p8;
+
+	ret = regulator_set_voltage_triplet(uphy->v3p3, 3050000, 3300000,
+					    3300000);
+	if (ret)
+		goto err_3p3;
+
+	ret = regulator_set_load(uphy->v3p3, 50000);
+	if (ret < 0)
+		goto err_3p3;
+
+	ret = regulator_enable(uphy->v3p3);
+	if (ret)
+		goto err_3p3;
+
+	for (seq = uphy->init_seq; seq->addr; seq++) {
+		ret = ulpi_write(ulpi, ULPI_EXT_VENDOR_SPECIFIC + seq->addr,
+				 seq->val);
+		if (ret)
+			goto err_ulpi;
+	}
+
+	if (uphy->reset) {
+		ret = reset_control_reset(uphy->reset);
+		if (ret)
+			goto err_ulpi;
+	}
+
+	if (uphy->vbus_edev) {
+		state = extcon_get_state(uphy->vbus_edev, EXTCON_USB);
+		/* setup initial state */
+		qcom_usb_hs_phy_vbus_notifier(&uphy->vbus_notify, state,
+					      uphy->vbus_edev);
+		ret = extcon_register_notifier(uphy->vbus_edev, EXTCON_USB,
+					       &uphy->vbus_notify);
+		if (ret)
+			goto err_ulpi;
+	}
+
+	return 0;
+err_ulpi:
+	regulator_disable(uphy->v3p3);
+err_3p3:
+	regulator_disable(uphy->v1p8);
+err_1p8:
+	clk_disable_unprepare(uphy->sleep_clk);
+err_sleep:
+	clk_disable_unprepare(uphy->ref_clk);
+	return ret;
+}
+
+static int qcom_usb_hs_phy_power_off(struct phy *phy)
+{
+	struct qcom_usb_hs_phy *uphy = phy_get_drvdata(phy);
+
+	if (uphy->vbus_edev)
+		extcon_unregister_notifier(uphy->vbus_edev, EXTCON_USB,
+					   &uphy->vbus_notify);
+	regulator_disable(uphy->v3p3);
+	regulator_disable(uphy->v1p8);
+	clk_disable_unprepare(uphy->sleep_clk);
+	clk_disable_unprepare(uphy->ref_clk);
+
+	return 0;
+}
+
+static const struct phy_ops qcom_usb_hs_phy_ops = {
+	.power_on = qcom_usb_hs_phy_power_on,
+	.power_off = qcom_usb_hs_phy_power_off,
+	.set_mode = qcom_usb_hs_phy_set_mode,
+	.owner = THIS_MODULE,
+};
+
+static int qcom_usb_hs_phy_probe(struct ulpi *ulpi)
+{
+	struct qcom_usb_hs_phy *uphy;
+	struct phy_provider *p;
+	struct clk *clk;
+	struct regulator *reg;
+	struct reset_control *reset;
+	int size;
+	int ret;
+
+	size = of_property_count_u8_elems(ulpi->dev.of_node, "qcom,init-seq");
+	if (size < 0)
+		size = 0;
+
+	uphy = devm_kzalloc(&ulpi->dev, struct_size(uphy, init_seq, (size / 2) + 1), GFP_KERNEL);
+	if (!uphy)
+		return -ENOMEM;
+	ulpi_set_drvdata(ulpi, uphy);
+	uphy->ulpi = ulpi;
+
+	ret = of_property_read_u8_array(ulpi->dev.of_node, "qcom,init-seq",
+					(u8 *)uphy->init_seq, size);
+	if (ret && size)
+		return ret;
+	/* NUL terminate */
+	uphy->init_seq[size / 2].addr = uphy->init_seq[size / 2].val = 0;
+
+	uphy->ref_clk = clk = devm_clk_get(&ulpi->dev, "ref");
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	uphy->sleep_clk = clk = devm_clk_get(&ulpi->dev, "sleep");
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	uphy->v1p8 = reg = devm_regulator_get(&ulpi->dev, "v1p8");
+	if (IS_ERR(reg))
+		return PTR_ERR(reg);
+
+	uphy->v3p3 = reg = devm_regulator_get(&ulpi->dev, "v3p3");
+	if (IS_ERR(reg))
+		return PTR_ERR(reg);
+
+	uphy->reset = reset = devm_reset_control_get(&ulpi->dev, "por");
+	if (IS_ERR(reset)) {
+		if (PTR_ERR(reset) == -EPROBE_DEFER)
+			return PTR_ERR(reset);
+		uphy->reset = NULL;
+	}
+
+	uphy->phy = devm_phy_create(&ulpi->dev, ulpi->dev.of_node,
+				    &qcom_usb_hs_phy_ops);
+	if (IS_ERR(uphy->phy))
+		return PTR_ERR(uphy->phy);
+
+	uphy->vbus_edev = extcon_get_edev_by_phandle(&ulpi->dev, 0);
+	if (IS_ERR(uphy->vbus_edev)) {
+		if (PTR_ERR(uphy->vbus_edev) != -ENODEV)
+			return PTR_ERR(uphy->vbus_edev);
+		uphy->vbus_edev = NULL;
+	}
+
+	uphy->vbus_notify.notifier_call = qcom_usb_hs_phy_vbus_notifier;
+	phy_set_drvdata(uphy->phy, uphy);
+
+	p = devm_of_phy_provider_register(&ulpi->dev, of_phy_simple_xlate);
+	return PTR_ERR_OR_ZERO(p);
+}
+
+static const struct of_device_id qcom_usb_hs_phy_match[] = {
+	{ .compatible = "qcom,usb-hs-phy", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, qcom_usb_hs_phy_match);
+
+static struct ulpi_driver qcom_usb_hs_phy_driver = {
+	.probe = qcom_usb_hs_phy_probe,
+	.driver = {
+		.name = "qcom_usb_hs_phy",
+		.of_match_table = qcom_usb_hs_phy_match,
+	},
+};
+module_ulpi_driver(qcom_usb_hs_phy_driver);
+
+MODULE_DESCRIPTION("Qualcomm USB HS phy");
+MODULE_LICENSE("GPL v2");