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, 204 insertions, 0 deletions

diff --git a/drivers/input/Kconfig b/drivers/input/Kconfig
new file mode 100644
index 000000000..88ecdf521
--- /dev/null
+++ b/drivers/input/Kconfig
@@ -0,0 +1,204 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Input device configuration
+#
+
+menu "Input device support"
+
+config INPUT
+	tristate "Generic input layer (needed for keyboard, mouse, ...)" if EXPERT
+	default y
+	help
+	  Say Y here if you have any input device (mouse, keyboard, tablet,
+	  joystick, steering wheel ...) connected to your system and want
+	  it to be available to applications. This includes standard PS/2
+	  keyboard and mouse.
+
+	  Say N here if you have a headless (no monitor, no keyboard) system.
+
+	  More information is available: <file:Documentation/input/input.rst>
+
+	  If unsure, say Y.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called input.
+
+if INPUT
+
+config INPUT_LEDS
+	tristate "Export input device LEDs in sysfs"
+	depends on LEDS_CLASS
+	default INPUT
+	help
+	  Say Y here if you would like to export LEDs on input devices
+	  as standard LED class devices in sysfs.
+
+	  If unsure, say Y.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called input-leds.
+
+config INPUT_FF_MEMLESS
+	tristate "Support for memoryless force-feedback devices"
+	help
+	  Say Y here if you have memoryless force-feedback input device
+	  such as Logitech WingMan Force 3D, ThrustMaster FireStorm Dual
+	  Power 2, or similar. You will also need to enable hardware-specific
+	  driver.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ff-memless.
+
+config INPUT_SPARSEKMAP
+	tristate "Sparse keymap support library"
+	help
+	  Say Y here if you are using a driver for an input
+	  device that uses sparse keymap. This option is only
+	  useful for out-of-tree drivers since in-tree drivers
+	  select it automatically.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called sparse-keymap.
+
+config INPUT_MATRIXKMAP
+	tristate "Matrix keymap support library"
+	help
+	  Say Y here if you are using a driver for an input
+	  device that uses matrix keymap. This option is only
+	  useful for out-of-tree drivers since in-tree drivers
+	  select it automatically.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called matrix-keymap.
+
+config INPUT_VIVALDIFMAP
+	tristate
+	help
+	  ChromeOS Vivaldi keymap support library. This is a hidden
+	  option so that drivers can use common code to parse and
+	  expose the vivaldi function row keymap.
+
+comment "Userland interfaces"
+
+config INPUT_MOUSEDEV
+	tristate "Mouse interface"
+	help
+	  Say Y here if you want your mouse to be accessible as char devices
+	  13:32+ - /dev/input/mouseX and 13:63 - /dev/input/mice as an
+	  emulated IntelliMouse Explorer PS/2 mouse. That way, all user space
+	  programs (including SVGAlib, GPM and X) will be able to use your
+	  mouse.
+
+	  If unsure, say Y.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called mousedev.
+
+config INPUT_MOUSEDEV_PSAUX
+	bool "Provide legacy /dev/psaux device"
+	depends on INPUT_MOUSEDEV
+	help
+	  Say Y here if you want your mouse also be accessible as char device
+	  10:1 - /dev/psaux. The data available through /dev/psaux is exactly
+	  the same as the data from /dev/input/mice.
+
+	  If unsure, say Y.
+
+config INPUT_MOUSEDEV_SCREEN_X
+	int "Horizontal screen resolution"
+	depends on INPUT_MOUSEDEV
+	default "1024"
+	help
+	  If you're using a digitizer, or a graphic tablet, and want to use
+	  it as a mouse then the mousedev driver needs to know the X window
+	  screen resolution you are using to correctly scale the data. If
+	  you're not using a digitizer, this value is ignored.
+
+config INPUT_MOUSEDEV_SCREEN_Y
+	int "Vertical screen resolution"
+	depends on INPUT_MOUSEDEV
+	default "768"
+	help
+	  If you're using a digitizer, or a graphic tablet, and want to use
+	  it as a mouse then the mousedev driver needs to know the X window
+	  screen resolution you are using to correctly scale the data. If
+	  you're not using a digitizer, this value is ignored.
+
+config INPUT_JOYDEV
+	tristate "Joystick interface"
+	help
+	  Say Y here if you want your joystick or gamepad to be
+	  accessible as char device 13:0+ - /dev/input/jsX device.
+
+	  If unsure, say Y.
+
+	  More information is available: <file:Documentation/input/joydev/joystick.rst>
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called joydev.
+
+config INPUT_EVDEV
+	tristate "Event interface"
+	help
+	  Say Y here if you want your input device events be accessible
+	  under char device 13:64+ - /dev/input/eventX in a generic way.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called evdev.
+
+config INPUT_KUNIT_TEST
+	tristate "KUnit tests for Input" if !KUNIT_ALL_TESTS
+	depends on INPUT && KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  Say Y here if you want to build the KUnit tests for the input
+	  subsystem.
+
+	  If in doubt, say "N".
+
+config INPUT_APMPOWER
+	tristate "Input Power Event -> APM Bridge" if EXPERT
+	depends on INPUT && APM_EMULATION
+	help
+	  Say Y here if you want suspend key events to trigger a user
+	  requested suspend through APM. This is useful on embedded
+	  systems where such behaviour is desired without userspace
+	  interaction. If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called apm-power.
+
+comment "Input Device Drivers"
+
+source "drivers/input/keyboard/Kconfig"
+
+source "drivers/input/mouse/Kconfig"
+
+source "drivers/input/joystick/Kconfig"
+
+source "drivers/input/tablet/Kconfig"
+
+source "drivers/input/touchscreen/Kconfig"
+
+source "drivers/input/misc/Kconfig"
+
+source "drivers/input/rmi4/Kconfig"
+
+endif
+
+menu "Hardware I/O ports"
+
+source "drivers/input/serio/Kconfig"
+
+source "drivers/input/gameport/Kconfig"
+
+endmenu
+
+endmenu
+