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, 66 insertions, 0 deletions

diff --git a/sound/soc/codecs/rt-sdw-common.h b/sound/soc/codecs/rt-sdw-common.h
new file mode 100644
index 000000000..4759516fe
--- /dev/null
+++ b/sound/soc/codecs/rt-sdw-common.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+//
+// rt-sdw-common.h
+//
+// Copyright(c) 2024 Realtek Semiconductor Corp.
+//
+
+/*
+ * This file defines common functions used with Realtek soundwire codecs.
+ */
+
+#ifndef __RT_SDW_COMMON_H__
+#define __RT_SDW_COMMON_H__
+
+#define SDCA_NUM_JACK_CODEC			0x01
+#define SDCA_NUM_MIC_ARRAY			0x02
+#define SDCA_NUM_HID				0x03
+#define SDCA_NUM_AMP				0x04
+#define RT_SDCA_CTL_SELECTED_MODE		0x01
+#define RT_SDCA_CTL_DETECTED_MODE		0x02
+#define RT_SDCA_CTL_HIDTX_CURRENT_OWNER		0x10
+#define RT_SDCA_CTL_HIDTX_MESSAGE_OFFSET	0x12
+
+struct rt_sdca_dmic_kctrl_priv {
+	unsigned int reg_base;
+	unsigned int count;
+	unsigned int max;
+	unsigned int invert;
+};
+
+#define RT_SDCA_PR_VALUE(xreg_base, xcount, xmax, xinvert) \
+	((unsigned long)&(struct rt_sdca_dmic_kctrl_priv) \
+		{.reg_base = xreg_base, .count = xcount, .max = xmax, \
+		.invert = xinvert})
+
+#define RT_SDCA_FU_CTRL(xname, reg_base, xmax, xinvert, xcount, \
+	xinfo, xget, xput) \
+{	.iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = (xname), \
+	.info = xinfo, \
+	.get = xget, \
+	.put = xput, \
+	.private_value = RT_SDCA_PR_VALUE(reg_base, xcount, xmax, xinvert)}
+
+#define RT_SDCA_EXT_TLV(xname, reg_base, xhandler_get,\
+	 xhandler_put, xcount, xmax, tlv_array, xinfo) \
+{	.iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = (xname), \
+	.access = SNDRV_CTL_ELEM_ACCESS_TLV_READ | \
+		 SNDRV_CTL_ELEM_ACCESS_READWRITE, \
+	.tlv.p = (tlv_array), \
+	.info = xinfo, \
+	.get = xhandler_get, .put = xhandler_put, \
+	.private_value = RT_SDCA_PR_VALUE(reg_base, xcount, xmax, 0) }
+
+
+int rt_sdca_index_write(struct regmap *map, unsigned int nid,
+	unsigned int reg, unsigned int value);
+int rt_sdca_index_read(struct regmap *map, unsigned int nid,
+	unsigned int reg, unsigned int *value);
+int rt_sdca_index_update_bits(struct regmap *map,
+	unsigned int nid, unsigned int reg, unsigned int mask, unsigned int val);
+int rt_sdca_btn_type(unsigned char *buffer);
+int rt_sdca_headset_detect(struct regmap *map, unsigned int entity_id);
+int rt_sdca_button_detect(struct regmap *map, unsigned int entity_id,
+	unsigned int hid_buf_addr, unsigned int hid_id);
+
+#endif /* __RT_SDW_COMMON_H__ */