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, 144 insertions, 0 deletions

diff --git a/sound/soc/codecs/wcd-common.c b/sound/soc/codecs/wcd-common.c
new file mode 100644
index 000000000..9016e9745
--- /dev/null
+++ b/sound/soc/codecs/wcd-common.c
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2025, Qualcomm Technologies, Inc. and/or its subsidiaries.
+
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/of.h>
+#include <linux/printk.h>
+#include <linux/component.h>
+#include <linux/pm_runtime.h>
+#include <linux/soundwire/sdw.h>
+#include <linux/soundwire/sdw_type.h>
+#include <linux/regmap.h>
+
+#include "wcd-common.h"
+
+#define WCD_MIN_MICBIAS_MV	1000
+#define WCD_DEF_MICBIAS_MV	1800
+#define WCD_MAX_MICBIAS_MV	2850
+
+#define SWRS_SCP_HOST_CLK_DIV2_CTL_BANK(m) (0xE0 + 0x10 * (m))
+
+int wcd_get_micb_vout_ctl_val(struct device *dev, u32 micb_mv)
+{
+	/* min micbias voltage is 1V and maximum is 2.85V */
+	if (micb_mv < WCD_MIN_MICBIAS_MV || micb_mv > WCD_MAX_MICBIAS_MV) {
+		dev_err(dev, "Unsupported micbias voltage (%u mV)\n", micb_mv);
+		return -EINVAL;
+	}
+
+	return (micb_mv - WCD_MIN_MICBIAS_MV) / 50;
+}
+EXPORT_SYMBOL_GPL(wcd_get_micb_vout_ctl_val);
+
+static int wcd_get_micbias_val(struct device *dev, int micb_num, u32 *micb_mv)
+{
+	char micbias[64];
+	int mv;
+
+	sprintf(micbias, "qcom,micbias%d-microvolt", micb_num);
+
+	if (of_property_read_u32(dev->of_node, micbias, &mv)) {
+		dev_err(dev, "%s value not found, using default\n", micbias);
+		mv = WCD_DEF_MICBIAS_MV;
+	} else {
+		/* convert it to milli volts */
+		mv = mv/1000;
+	}
+	if (micb_mv)
+		*micb_mv = mv;
+
+	mv = wcd_get_micb_vout_ctl_val(dev, mv);
+	if (mv < 0) {
+		dev_err(dev, "Unsupported %s voltage (%d mV), falling back to default (%d mV)\n",
+				micbias, mv, WCD_DEF_MICBIAS_MV);
+		return wcd_get_micb_vout_ctl_val(dev, WCD_DEF_MICBIAS_MV);
+	}
+
+	return mv;
+}
+
+int wcd_dt_parse_micbias_info(struct wcd_common *common)
+{
+	int ret, i;
+
+	for (i = 0; i < common->max_bias; i++) {
+		ret = wcd_get_micbias_val(common->dev, i + 1, &common->micb_mv[i]);
+		if (ret < 0)
+			return ret;
+		common->micb_vout[i] = ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(wcd_dt_parse_micbias_info);
+
+static int wcd_sdw_component_bind(struct device *dev, struct device *master, void *data)
+{
+	pm_runtime_set_autosuspend_delay(dev, 3000);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
+	return 0;
+}
+
+static void wcd_sdw_component_unbind(struct device *dev, struct device *master, void *data)
+{
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+	pm_runtime_dont_use_autosuspend(dev);
+}
+
+const struct component_ops wcd_sdw_component_ops = {
+	.bind = wcd_sdw_component_bind,
+	.unbind = wcd_sdw_component_unbind,
+};
+EXPORT_SYMBOL_GPL(wcd_sdw_component_ops);
+
+int wcd_update_status(struct sdw_slave *slave, enum sdw_slave_status status)
+{
+	struct regmap *regmap = dev_get_regmap(&slave->dev, NULL);
+
+	if (regmap && status == SDW_SLAVE_ATTACHED) {
+		/* Write out any cached changes that happened between probe and attach */
+		regcache_cache_only(regmap, false);
+		return regcache_sync(regmap);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(wcd_update_status);
+
+int wcd_bus_config(struct sdw_slave *slave, struct sdw_bus_params *params)
+{
+	sdw_write(slave, SWRS_SCP_HOST_CLK_DIV2_CTL_BANK(params->next_bank), 0x01);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(wcd_bus_config);
+
+int wcd_interrupt_callback(struct sdw_slave *slave, struct irq_domain *slave_irq,
+		unsigned int wcd_intr_status0, unsigned int wcd_intr_status1,
+		unsigned int wcd_intr_status2)
+{
+	struct regmap *regmap = dev_get_regmap(&slave->dev, NULL);
+	u32 sts1, sts2, sts3;
+
+	do {
+		handle_nested_irq(irq_find_mapping(slave_irq, 0));
+		regmap_read(regmap, wcd_intr_status0, &sts1);
+		regmap_read(regmap, wcd_intr_status1, &sts2);
+		regmap_read(regmap, wcd_intr_status2, &sts3);
+
+	} while (sts1 || sts2 || sts3);
+
+	return IRQ_HANDLED;
+}
+EXPORT_SYMBOL_GPL(wcd_interrupt_callback);
+
+MODULE_DESCRIPTION("Common Qualcomm WCD Codec helpers driver");
+MODULE_LICENSE("GPL");