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, 113 insertions, 0 deletions

diff --git a/drivers/misc/mei/Kconfig b/drivers/misc/mei/Kconfig
new file mode 100644
index 000000000..2d1bc5b4d
--- /dev/null
+++ b/drivers/misc/mei/Kconfig
@@ -0,0 +1,113 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2003-2019, Intel Corporation. All rights reserved.
+config INTEL_MEI
+	tristate "Intel Management Engine Interface"
+	depends on PCI
+	depends on X86 || DRM_XE!=n || COMPILE_TEST
+	default X86_64 || MATOM
+	help
+	  The Intel Management Engine (Intel ME) provides Manageability,
+	  Security and Media services for system containing Intel chipsets.
+	  if selected /dev/mei misc device will be created.
+
+	  For more information see
+	  <https://software.intel.com/en-us/manageability/>
+
+if INTEL_MEI
+
+config INTEL_MEI_ME
+	tristate "ME Enabled Intel Chipsets"
+	default y
+	help
+	  MEI support for ME Enabled Intel chipsets.
+
+	  Supported Chipsets are:
+	  7 Series Chipset Family
+	  6 Series Chipset Family
+	  5 Series Chipset Family
+	  4 Series Chipset Family
+	  Mobile 4 Series Chipset Family
+	  ICH9
+	  82946GZ/GL
+	  82G35 Express
+	  82Q963/Q965
+	  82P965/G965
+	  Mobile PM965/GM965
+	  Mobile GME965/GLE960
+	  82Q35 Express
+	  82G33/G31/P35/P31 Express
+	  82Q33 Express
+	  82X38/X48 Express
+
+config INTEL_MEI_TXE
+	tristate "Intel Trusted Execution Environment with ME Interface"
+	help
+	  MEI Support for Trusted Execution Environment device on Intel SoCs
+
+	  Supported SoCs:
+	  Intel Bay Trail
+
+config INTEL_MEI_GSC
+	tristate "Intel MEI GSC embedded device"
+	depends on INTEL_MEI_ME
+	depends on DRM_I915!=n || DRM_XE!=n || COMPILE_TEST
+	help
+	  Intel auxiliary driver for GSC devices embedded in Intel graphics devices.
+
+	  An MEI device here called GSC can be embedded in an
+	  Intel graphics devices, to support a range of chassis
+	  tasks such as graphics card firmware update and security
+	  tasks.
+
+config INTEL_MEI_CSC
+	tristate "Intel MEI CSC embedded device"
+	depends on INTEL_MEI_ME
+	help
+	  Intel PCI driver for the chassis controller embedded in Intel graphics devices.
+
+	  An MEI device here called CSC can be embedded in discrete
+	  Intel graphics devices, to support a range of chassis
+	  tasks such as graphics card firmware update and security
+	  tasks.
+
+config INTEL_MEI_VSC_HW
+	tristate "Intel visual sensing controller device transport driver"
+	depends on ACPI && SPI
+	depends on GPIOLIB || COMPILE_TEST
+	help
+	  Intel SPI transport driver between host and Intel visual sensing
+	  controller (IVSC) device.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called mei-vsc-hw.
+
+config INTEL_MEI_VSC
+	tristate "Intel visual sensing controller device with ME interface"
+	depends on INTEL_MEI_VSC_HW
+	help
+	  Intel MEI over SPI driver for Intel visual sensing controller
+	  (IVSC) device embedded in IA platform. It supports camera sharing
+	  between IVSC for context sensing and IPU for typical media usage.
+	  Select this config should enable transport layer for IVSC device.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called mei-vsc.
+
+config INTEL_MEI_LB
+	tristate "Intel Late Binding (LB) support on ME Interface"
+	depends on INTEL_MEI_ME
+	depends on DRM_XE!=n || COMPILE_TEST
+	help
+	  Enable support for Intel Late Binding (LB) via the MEI interface.
+
+	  Late Binding is a method for applying firmware updates at runtime,
+	  allowing the Intel Xe driver to load firmware payloads such as
+	  fan controller or voltage regulator. These firmware updates are
+	  authenticated and versioned, and do not require firmware flashing
+	  or system reboot.
+
+source "drivers/misc/mei/hdcp/Kconfig"
+source "drivers/misc/mei/pxp/Kconfig"
+source "drivers/misc/mei/gsc_proxy/Kconfig"
+
+endif