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, 292 insertions, 0 deletions

diff --git a/drivers/acpi/acpica/acdebug.h b/drivers/acpi/acpica/acdebug.h
new file mode 100644
index 000000000..09ab8b3db
--- /dev/null
+++ b/drivers/acpi/acpica/acdebug.h
@@ -0,0 +1,292 @@
+/* SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 */
+/******************************************************************************
+ *
+ * Name: acdebug.h - ACPI/AML debugger
+ *
+ * Copyright (C) 2000 - 2026, Intel Corp.
+ *
+ *****************************************************************************/
+
+#ifndef __ACDEBUG_H__
+#define __ACDEBUG_H__
+
+/* The debugger is used in conjunction with the disassembler most of time */
+
+#ifdef ACPI_DISASSEMBLER
+#include "acdisasm.h"
+#endif
+
+#define ACPI_DEBUG_BUFFER_SIZE      0x4000	/* 16K buffer for return objects */
+#define ACPI_DEBUG_LENGTH_FORMAT    " (%.4X bits, %.3X bytes)"
+
+struct acpi_db_command_info {
+	const char *name;	/* Command Name */
+	u8 min_args;		/* Minimum arguments required */
+};
+
+struct acpi_db_command_help {
+	u8 line_count;		/* Number of help lines */
+	char *invocation;	/* Command Invocation */
+	char *description;	/* Command Description */
+};
+
+struct acpi_db_argument_info {
+	const char *name;	/* Argument Name */
+};
+
+struct acpi_db_execute_walk {
+	u32 count;
+	u32 max_count;
+	char name_seg[ACPI_NAMESEG_SIZE + 1];
+};
+
+#define PARAM_LIST(pl)                  pl
+
+#define EX_NO_SINGLE_STEP               1
+#define EX_SINGLE_STEP                  2
+#define EX_ALL                          4
+
+/*
+ * dbxface - external debugger interfaces
+ */
+ACPI_DBR_DEPENDENT_RETURN_OK(acpi_status
+			     acpi_db_single_step(struct acpi_walk_state
+						 *walk_state,
+						 union acpi_parse_object *op,
+						 u32 op_type))
+ ACPI_DBR_DEPENDENT_RETURN_VOID(void
+				acpi_db_signal_break_point(struct
+							   acpi_walk_state
+							   *walk_state))
+
+/*
+ * dbcmds - debug commands and output routines
+ */
+struct acpi_namespace_node *acpi_db_convert_to_node(char *in_string);
+
+void acpi_db_display_table_info(char *table_arg);
+
+void acpi_db_display_template(char *buffer_arg);
+
+void acpi_db_unload_acpi_table(char *name);
+
+void acpi_db_send_notify(char *name, u32 value);
+
+void acpi_db_display_interfaces(char *action_arg, char *interface_name_arg);
+
+acpi_status acpi_db_sleep(char *object_arg);
+
+void acpi_db_trace(char *enable_arg, char *method_arg, char *once_arg);
+
+void acpi_db_display_locks(void);
+
+void acpi_db_display_resources(char *object_arg);
+
+ACPI_HW_DEPENDENT_RETURN_VOID(void acpi_db_display_gpes(void))
+
+void acpi_db_display_handlers(void);
+
+ACPI_HW_DEPENDENT_RETURN_VOID(void
+			      acpi_db_generate_gpe(char *gpe_arg,
+						   char *block_arg))
+ACPI_HW_DEPENDENT_RETURN_VOID(void acpi_db_generate_sci(void))
+
+void acpi_db_execute_test(char *type_arg);
+
+/*
+ * dbconvert - miscellaneous conversion routines
+ */
+acpi_status acpi_db_hex_char_to_value(int hex_char, u8 *return_value);
+
+acpi_status acpi_db_convert_to_package(char *string, union acpi_object *object);
+
+acpi_status
+acpi_db_convert_to_object(acpi_object_type type,
+			  char *string, union acpi_object *object);
+
+u8 *acpi_db_encode_pld_buffer(struct acpi_pld_info *pld_info);
+
+void acpi_db_dump_pld_buffer(union acpi_object *obj_desc);
+
+/*
+ * dbmethod - control method commands
+ */
+void
+acpi_db_set_method_breakpoint(char *location,
+			      struct acpi_walk_state *walk_state,
+			      union acpi_parse_object *op);
+
+void acpi_db_set_method_call_breakpoint(union acpi_parse_object *op);
+
+void acpi_db_set_method_data(char *type_arg, char *index_arg, char *value_arg);
+
+acpi_status acpi_db_disassemble_method(char *name);
+
+void acpi_db_disassemble_aml(char *statements, union acpi_parse_object *op);
+
+void acpi_db_evaluate_predefined_names(void);
+
+void acpi_db_evaluate_all(char *name_seg);
+
+/*
+ * dbnames - namespace commands
+ */
+void acpi_db_set_scope(char *name);
+
+void acpi_db_dump_namespace(char *start_arg, char *depth_arg);
+
+void acpi_db_dump_namespace_paths(void);
+
+void acpi_db_dump_namespace_by_owner(char *owner_arg, char *depth_arg);
+
+acpi_status acpi_db_find_name_in_namespace(char *name_arg);
+
+void acpi_db_check_predefined_names(void);
+
+acpi_status
+acpi_db_display_objects(char *obj_type_arg, char *display_count_arg);
+
+void acpi_db_check_integrity(void);
+
+void acpi_db_find_references(char *object_arg);
+
+void acpi_db_get_bus_info(void);
+
+acpi_status acpi_db_display_fields(u32 address_space_id);
+
+/*
+ * dbdisply - debug display commands
+ */
+void acpi_db_display_method_info(union acpi_parse_object *op);
+
+void acpi_db_decode_and_display_object(char *target, char *output_type);
+
+ACPI_DBR_DEPENDENT_RETURN_VOID(void
+			       acpi_db_display_result_object(union
+							     acpi_operand_object
+							     *obj_desc,
+							     struct
+							     acpi_walk_state
+							     *walk_state))
+
+acpi_status acpi_db_display_all_methods(char *display_count_arg);
+
+void acpi_db_display_arguments(void);
+
+void acpi_db_display_locals(void);
+
+void acpi_db_display_results(void);
+
+void acpi_db_display_calling_tree(void);
+
+void acpi_db_display_object_type(char *object_arg);
+
+ACPI_DBR_DEPENDENT_RETURN_VOID(void
+			       acpi_db_display_argument_object(union
+							       acpi_operand_object
+							       *obj_desc,
+							       struct
+							       acpi_walk_state
+							       *walk_state))
+
+/*
+ * dbexec - debugger control method execution
+ */
+void
+acpi_db_execute(char *name, char **args, acpi_object_type *types, u32 flags);
+
+void
+acpi_db_create_execution_thread(char *method_name_arg,
+				char **arguments, acpi_object_type *types);
+
+void
+acpi_db_create_execution_threads(char *num_threads_arg,
+				 char *num_loops_arg, char *method_name_arg);
+
+void acpi_db_delete_objects(u32 count, union acpi_object *objects);
+
+#ifdef ACPI_DBG_TRACK_ALLOCATIONS
+u32 acpi_db_get_cache_info(struct acpi_memory_list *cache);
+#endif
+
+/*
+ * dbfileio - Debugger file I/O commands
+ */
+acpi_object_type
+acpi_db_match_argument(char *user_argument,
+		       struct acpi_db_argument_info *arguments);
+
+void acpi_db_close_debug_file(void);
+
+void acpi_db_open_debug_file(char *name);
+
+acpi_status acpi_db_load_acpi_table(char *filename);
+
+acpi_status acpi_db_load_tables(struct acpi_new_table_desc *list_head);
+
+/*
+ * dbhistry - debugger HISTORY command
+ */
+void acpi_db_add_to_history(char *command_line);
+
+void acpi_db_display_history(void);
+
+char *acpi_db_get_from_history(char *command_num_arg);
+
+char *acpi_db_get_history_by_index(u32 commandd_num);
+
+/*
+ * dbinput - user front-end to the AML debugger
+ */
+acpi_status
+acpi_db_command_dispatch(char *input_buffer,
+			 struct acpi_walk_state *walk_state,
+			 union acpi_parse_object *op);
+
+void ACPI_SYSTEM_XFACE acpi_db_execute_thread(void *context);
+
+acpi_status acpi_db_user_commands(void);
+
+char *acpi_db_get_next_token(char *string,
+			     char **next, acpi_object_type *return_type);
+
+/*
+ * dbobject
+ */
+void acpi_db_decode_internal_object(union acpi_operand_object *obj_desc);
+
+void
+acpi_db_display_internal_object(union acpi_operand_object *obj_desc,
+				struct acpi_walk_state *walk_state);
+
+void acpi_db_decode_arguments(struct acpi_walk_state *walk_state);
+
+void acpi_db_decode_locals(struct acpi_walk_state *walk_state);
+
+void
+acpi_db_dump_method_info(acpi_status status,
+			 struct acpi_walk_state *walk_state);
+
+/*
+ * dbstats - Generation and display of ACPI table statistics
+ */
+void acpi_db_generate_statistics(union acpi_parse_object *root, u8 is_method);
+
+acpi_status acpi_db_display_statistics(char *type_arg);
+
+/*
+ * dbutils - AML debugger utilities
+ */
+void acpi_db_set_output_destination(u32 where);
+
+void acpi_db_dump_external_object(union acpi_object *obj_desc, u32 level);
+
+void acpi_db_prep_namestring(char *name);
+
+struct acpi_namespace_node *acpi_db_local_ns_lookup(char *name);
+
+void acpi_db_uint32_to_hex_string(u32 value, char *buffer);
+
+void acpi_db_generate_interrupt(char *gsiv_arg);
+
+#endif				/* __ACDEBUG_H__ */