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, 163 insertions, 0 deletions

diff --git a/drivers/input/misc/twl4030-pwrbutton.c b/drivers/input/misc/twl4030-pwrbutton.c
new file mode 100644
index 000000000..3e94a5995
--- /dev/null
+++ b/drivers/input/misc/twl4030-pwrbutton.c
@@ -0,0 +1,163 @@
+/*
+ * TWL4030 Power Button Input Driver
+ *
+ * Copyright (C) 2008-2009 Nokia Corporation
+ *
+ * Written by Peter De Schrijver <peter.de-schrijver@nokia.com>
+ * Several fixes by Felipe Balbi <felipe.balbi@nokia.com>
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License. See the file "COPYING" in the main directory of this
+ * archive for more details.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/bits.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/property.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/twl.h>
+
+#define PWR_PWRON_IRQ BIT(0)
+
+struct twl_pwrbutton_chipdata {
+	u8 status_reg;
+	bool need_manual_irq;
+};
+
+static const struct twl_pwrbutton_chipdata twl4030_chipdata = {
+	.status_reg = 0xf,
+	.need_manual_irq = false,
+};
+
+static const struct twl_pwrbutton_chipdata twl6030_chipdata = {
+	.status_reg = 0x2,
+	.need_manual_irq = true,
+};
+
+static irqreturn_t powerbutton_irq(int irq, void *_pwr)
+{
+	struct input_dev *pwr = _pwr;
+	const struct twl_pwrbutton_chipdata *pdata = dev_get_drvdata(pwr->dev.parent);
+	int err;
+	u8 value;
+
+	err = twl_i2c_read_u8(TWL_MODULE_PM_MASTER, &value, pdata->status_reg);
+	if (!err)  {
+		pm_wakeup_event(pwr->dev.parent, 0);
+		input_report_key(pwr, KEY_POWER, value & PWR_PWRON_IRQ);
+		input_sync(pwr);
+	} else {
+		dev_err(pwr->dev.parent, "twl4030: i2c error %d while reading"
+			" TWL4030 PM_MASTER STS_HW_CONDITIONS register\n", err);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int twl4030_pwrbutton_probe(struct platform_device *pdev)
+{
+	const struct twl_pwrbutton_chipdata *pdata;
+	struct input_dev *pwr;
+	int irq = platform_get_irq(pdev, 0);
+	int err;
+
+	pdata = device_get_match_data(&pdev->dev);
+	if (!pdata)
+		return -EINVAL;
+
+	platform_set_drvdata(pdev, (void *)pdata);
+
+	pwr = devm_input_allocate_device(&pdev->dev);
+	if (!pwr) {
+		dev_err(&pdev->dev, "Can't allocate power button\n");
+		return -ENOMEM;
+	}
+
+	input_set_capability(pwr, EV_KEY, KEY_POWER);
+	pwr->name = "twl4030_pwrbutton";
+	pwr->phys = "twl4030_pwrbutton/input0";
+	pwr->dev.parent = &pdev->dev;
+
+	err = devm_request_threaded_irq(&pdev->dev, irq, NULL, powerbutton_irq,
+			IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING |
+			IRQF_ONESHOT,
+			"twl4030_pwrbutton", pwr);
+	if (err < 0) {
+		dev_err(&pdev->dev, "Can't get IRQ for pwrbutton: %d\n", err);
+		return err;
+	}
+
+	err = input_register_device(pwr);
+	if (err) {
+		dev_err(&pdev->dev, "Can't register power button: %d\n", err);
+		return err;
+	}
+
+	if (pdata->need_manual_irq) {
+		err = twl6030_interrupt_unmask(0x01, REG_INT_MSK_LINE_A);
+		if (err)
+			return err;
+
+		err = twl6030_interrupt_unmask(0x01, REG_INT_MSK_STS_A);
+		if (err)
+			return err;
+	}
+
+	device_init_wakeup(&pdev->dev, true);
+
+	return 0;
+}
+
+static void twl4030_pwrbutton_remove(struct platform_device *pdev)
+{
+	const struct twl_pwrbutton_chipdata *pdata = platform_get_drvdata(pdev);
+
+	if (pdata->need_manual_irq) {
+		twl6030_interrupt_mask(0x01, REG_INT_MSK_LINE_A);
+		twl6030_interrupt_mask(0x01, REG_INT_MSK_STS_A);
+	}
+}
+
+static const struct of_device_id twl4030_pwrbutton_dt_match_table[] = {
+	{
+		.compatible = "ti,twl4030-pwrbutton",
+		.data = &twl4030_chipdata,
+	},
+	{
+		.compatible = "ti,twl6030-pwrbutton",
+		.data = &twl6030_chipdata,
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, twl4030_pwrbutton_dt_match_table);
+
+static struct platform_driver twl4030_pwrbutton_driver = {
+	.probe		= twl4030_pwrbutton_probe,
+	.remove		= twl4030_pwrbutton_remove,
+	.driver		= {
+		.name	= "twl4030_pwrbutton",
+		.of_match_table = twl4030_pwrbutton_dt_match_table,
+	},
+};
+module_platform_driver(twl4030_pwrbutton_driver);
+
+MODULE_ALIAS("platform:twl4030_pwrbutton");
+MODULE_DESCRIPTION("Triton2 Power Button");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Peter De Schrijver <peter.de-schrijver@nokia.com>");
+MODULE_AUTHOR("Felipe Balbi <felipe.balbi@nokia.com>");
+