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, 79 insertions, 0 deletions

diff --git a/sound/soc/sof/sof-client.h b/sound/soc/sof/sof-client.h
new file mode 100644
index 000000000..3b02506c0
--- /dev/null
+++ b/sound/soc/sof/sof-client.h
@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __SOC_SOF_CLIENT_H
+#define __SOC_SOF_CLIENT_H
+
+#include <linux/auxiliary_bus.h>
+#include <linux/device.h>
+#include <linux/list.h>
+#include <sound/sof.h>
+
+struct sof_ipc_fw_version;
+struct sof_ipc_cmd_hdr;
+struct snd_sof_dev;
+struct dentry;
+
+struct sof_ipc4_fw_module;
+
+/**
+ * struct sof_client_dev - SOF client device
+ * @auxdev:	auxiliary device
+ * @data:	device specific data
+ */
+struct sof_client_dev {
+	struct auxiliary_device auxdev;
+	void *data;
+};
+
+#define auxiliary_dev_to_sof_client_dev(auxiliary_dev) \
+	container_of(auxiliary_dev, struct sof_client_dev, auxdev)
+
+#define dev_to_sof_client_dev(dev) \
+	container_of(to_auxiliary_dev(dev), struct sof_client_dev, auxdev)
+
+int sof_client_ipc_tx_message(struct sof_client_dev *cdev, void *ipc_msg,
+			      void *reply_data, size_t reply_bytes);
+static inline int sof_client_ipc_tx_message_no_reply(struct sof_client_dev *cdev, void *ipc_msg)
+{
+	return sof_client_ipc_tx_message(cdev, ipc_msg, NULL, 0);
+}
+int sof_client_ipc_set_get_data(struct sof_client_dev *cdev, void *ipc_msg,
+				bool set);
+
+struct sof_ipc4_fw_module *sof_client_ipc4_find_module(struct sof_client_dev *c, const guid_t *u);
+struct snd_sof_widget *sof_client_ipc4_find_swidget_by_id(struct sof_client_dev *cdev,
+							  u32 module_id, int instance_id);
+
+struct dentry *sof_client_get_debugfs_root(struct sof_client_dev *cdev);
+struct device *sof_client_get_dma_dev(struct sof_client_dev *cdev);
+const struct sof_ipc_fw_version *sof_client_get_fw_version(struct sof_client_dev *cdev);
+size_t sof_client_get_ipc_max_payload_size(struct sof_client_dev *cdev);
+enum sof_ipc_type sof_client_get_ipc_type(struct sof_client_dev *cdev);
+
+/* DSP/firmware boot request */
+int sof_client_boot_dsp(struct sof_client_dev *cdev);
+
+/* module refcount management of SOF core */
+int sof_client_core_module_get(struct sof_client_dev *cdev);
+void sof_client_core_module_put(struct sof_client_dev *cdev);
+
+/* IPC notification */
+typedef void (*sof_client_event_callback)(struct sof_client_dev *cdev, void *msg_buf);
+
+int sof_client_register_ipc_rx_handler(struct sof_client_dev *cdev,
+				       u32 ipc_msg_type,
+				       sof_client_event_callback callback);
+void sof_client_unregister_ipc_rx_handler(struct sof_client_dev *cdev,
+					  u32 ipc_msg_type);
+
+/* DSP state notification and query */
+typedef void (*sof_client_fw_state_callback)(struct sof_client_dev *cdev,
+					     enum sof_fw_state state);
+
+int sof_client_register_fw_state_handler(struct sof_client_dev *cdev,
+					 sof_client_fw_state_callback callback);
+void sof_client_unregister_fw_state_handler(struct sof_client_dev *cdev);
+enum sof_fw_state sof_client_get_fw_state(struct sof_client_dev *cdev);
+int sof_client_ipc_rx_message(struct sof_client_dev *cdev, void *ipc_msg, void *msg_buf);
+
+#endif /* __SOC_SOF_CLIENT_H */