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, 154 insertions, 0 deletions

diff --git a/sound/soc/codecs/rt1015p.c b/sound/soc/codecs/rt1015p.c
new file mode 100644
index 000000000..44e7fe3c3
--- /dev/null
+++ b/sound/soc/codecs/rt1015p.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// rt1015p.c  --  RT1015P ALSA SoC audio amplifier driver
+//
+// Copyright 2020 The Linux Foundation. All rights reserved.
+
+#include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <sound/pcm.h>
+#include <sound/soc.h>
+#include <sound/soc-dai.h>
+#include <sound/soc-dapm.h>
+
+struct rt1015p_priv {
+	struct gpio_desc *sdb;
+	bool calib_done;
+};
+
+static int rt1015p_sdb_event(struct snd_soc_dapm_widget *w,
+		struct snd_kcontrol *kcontrol, int event)
+{
+	struct snd_soc_component *component =
+		snd_soc_dapm_to_component(w->dapm);
+	struct rt1015p_priv *rt1015p =
+		snd_soc_component_get_drvdata(component);
+
+	if (!rt1015p->sdb)
+		return 0;
+
+	switch (event) {
+	case SND_SOC_DAPM_PRE_PMU:
+		gpiod_set_value_cansleep(rt1015p->sdb, 1);
+		dev_dbg(component->dev, "set sdb to 1");
+
+		if (!rt1015p->calib_done) {
+			msleep(300);
+			rt1015p->calib_done = true;
+		}
+		break;
+	case SND_SOC_DAPM_POST_PMD:
+		gpiod_set_value_cansleep(rt1015p->sdb, 0);
+		dev_dbg(component->dev, "set sdb to 0");
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static const struct snd_soc_dapm_widget rt1015p_dapm_widgets[] = {
+	SND_SOC_DAPM_OUTPUT("Speaker"),
+	SND_SOC_DAPM_OUT_DRV_E("SDB", SND_SOC_NOPM, 0, 0, NULL, 0,
+			rt1015p_sdb_event,
+			SND_SOC_DAPM_PRE_PMU | SND_SOC_DAPM_POST_PMD),
+};
+
+static const struct snd_soc_dapm_route rt1015p_dapm_routes[] = {
+	{"SDB", NULL, "HiFi Playback"},
+	{"Speaker", NULL, "SDB"},
+};
+
+#ifdef CONFIG_PM
+static int rt1015p_suspend(struct snd_soc_component *component)
+{
+	struct rt1015p_priv *rt1015p = snd_soc_component_get_drvdata(component);
+
+	rt1015p->calib_done = false;
+	return 0;
+}
+#else
+#define rt1015p_suspend NULL
+#endif
+
+static const struct snd_soc_component_driver rt1015p_component_driver = {
+	.suspend		= rt1015p_suspend,
+	.dapm_widgets		= rt1015p_dapm_widgets,
+	.num_dapm_widgets	= ARRAY_SIZE(rt1015p_dapm_widgets),
+	.dapm_routes		= rt1015p_dapm_routes,
+	.num_dapm_routes	= ARRAY_SIZE(rt1015p_dapm_routes),
+	.idle_bias_on		= 1,
+	.use_pmdown_time	= 1,
+	.endianness		= 1,
+};
+
+static struct snd_soc_dai_driver rt1015p_dai_driver = {
+	.name = "HiFi",
+	.playback = {
+		.stream_name	= "HiFi Playback",
+		.formats	= SNDRV_PCM_FMTBIT_S24 |
+					SNDRV_PCM_FMTBIT_S32,
+		.rates		= SNDRV_PCM_RATE_48000,
+		.channels_min	= 1,
+		.channels_max	= 2,
+	},
+};
+
+static int rt1015p_platform_probe(struct platform_device *pdev)
+{
+	struct rt1015p_priv *rt1015p;
+
+	rt1015p = devm_kzalloc(&pdev->dev, sizeof(*rt1015p), GFP_KERNEL);
+	if (!rt1015p)
+		return -ENOMEM;
+
+	rt1015p->sdb = devm_gpiod_get_optional(&pdev->dev,
+				"sdb", GPIOD_OUT_LOW);
+	if (IS_ERR(rt1015p->sdb))
+		return PTR_ERR(rt1015p->sdb);
+
+	dev_set_drvdata(&pdev->dev, rt1015p);
+
+	return devm_snd_soc_register_component(&pdev->dev,
+			&rt1015p_component_driver,
+			&rt1015p_dai_driver, 1);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id rt1015p_device_id[] = {
+	{ .compatible = "realtek,rt1015p" },
+	{ .compatible = "realtek,rt1019p" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, rt1015p_device_id);
+#endif
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id rt1015p_acpi_match[] = {
+	{ "RTL1015", 0},
+	{ "RTL1019", 0},
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, rt1015p_acpi_match);
+#endif
+
+static struct platform_driver rt1015p_platform_driver = {
+	.driver = {
+		.name = "rt1015p",
+		.of_match_table = of_match_ptr(rt1015p_device_id),
+		.acpi_match_table = ACPI_PTR(rt1015p_acpi_match),
+	},
+	.probe = rt1015p_platform_probe,
+};
+module_platform_driver(rt1015p_platform_driver);
+
+MODULE_DESCRIPTION("ASoC RT1015P driver");
+MODULE_LICENSE("GPL v2");