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/arch/arm/Kconfig.platforms b/arch/arm/Kconfig.platforms
new file mode 100644
index 000000000..2e118b65f
--- /dev/null
+++ b/arch/arm/Kconfig.platforms
@@ -0,0 +1,204 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+menu "Platform selection"
+	depends on MMU
+
+comment "CPU Core family selection"
+
+config ARCH_MULTI_V4
+	bool "ARMv4 based platforms (FA526, StrongARM)"
+	depends on !ARCH_MULTI_V6_V7
+	select ARCH_MULTI_V4_V5
+	select CPU_FA526 if !(CPU_SA110 || CPU_SA1100)
+
+config ARCH_MULTI_V4T
+	bool "ARMv4T based platforms (ARM720T, ARM920T, ...)"
+	depends on !ARCH_MULTI_V6_V7
+	select ARCH_MULTI_V4_V5
+	select CPU_ARM920T if !(CPU_ARM7TDMI || CPU_ARM720T || \
+		CPU_ARM740T || CPU_ARM9TDMI || CPU_ARM922T || \
+		CPU_ARM925T || CPU_ARM940T)
+
+config ARCH_MULTI_V5
+	bool "ARMv5 based platforms (ARM926T, XSCALE, PJ1, ...)"
+	depends on !ARCH_MULTI_V6_V7
+	select ARCH_MULTI_V4_V5
+	select CPU_ARM926T if !(CPU_ARM946E || CPU_ARM1020 || \
+		CPU_ARM1020E || CPU_ARM1022 || CPU_ARM1026 || \
+		CPU_XSCALE || CPU_XSC3 || CPU_MOHAWK || CPU_FEROCEON)
+
+config ARCH_MULTI_V4_V5
+	bool
+
+config ARCH_MULTI_V6
+	bool "ARMv6 based platforms (ARM11)"
+	select ARCH_MULTI_V6_V7
+	select CPU_ARM1176
+
+config ARCH_MULTI_V7
+	bool "ARMv7 based platforms (Cortex-A, PJ4, Scorpion, Krait)"
+	default y
+	select ARCH_MULTI_V6_V7
+	select CPU_V7
+	select HAVE_SMP
+
+config ARCH_MULTI_V6_V7
+	bool
+	select MIGHT_HAVE_CACHE_L2X0
+
+config ARCH_MULTI_CPU_AUTO
+	def_bool !(ARCH_MULTI_V4 || ARCH_MULTI_V4T || ARCH_MULTI_V6_V7)
+	select ARCH_MULTI_V5
+
+endmenu
+
+config ARCH_VIRT
+	bool "Dummy Virtual Machine"
+	depends on ARCH_MULTI_V7
+	select ARM_AMBA
+	select ARM_GIC
+	select ARM_GIC_V2M if PCI
+	select ARM_GIC_V3
+	select ARM_GIC_V3_ITS if PCI
+	select ARM_PSCI
+	select HAVE_ARM_ARCH_TIMER
+
+config ARCH_AIROHA
+	bool "Airoha SoC Support"
+	depends on ARCH_MULTI_V7
+	select ARM_AMBA
+	select ARM_GIC
+	select ARM_GIC_V3
+	select ARM_PSCI
+	select HAVE_ARM_ARCH_TIMER
+	help
+	  Support for Airoha EN7523 SoCs
+
+config MACH_ASM9260
+	bool "Alphascale ASM9260"
+	depends on ARCH_MULTI_V5
+	depends on CPU_LITTLE_ENDIAN
+	select CPU_ARM926T
+	select ASM9260_TIMER
+	help
+	  Support for Alphascale ASM9260 based platform.
+
+menuconfig ARCH_HPE
+	bool "HPE SoC support"
+	depends on ARCH_MULTI_V7
+	help
+	  This enables support for HPE ARM based BMC chips.
+
+if ARCH_HPE
+
+config ARCH_HPE_GXP
+	bool "HPE GXP SoC"
+	depends on ARCH_MULTI_V7
+	select ARM_VIC
+	select GENERIC_IRQ_CHIP
+	select CLKSRC_MMIO
+	help
+	  HPE GXP is the name of the HPE Soc. This SoC is used to implement many
+	  BMC features at HPE. It supports ARMv7 architecture based on the Cortex
+	  A9 core. It is capable of using an AXI bus to which a memory controller
+	  is attached. It has multiple SPI interfaces to connect boot flash and
+	  BIOS flash. It uses a 10/100/1000 MAC for network connectivity. It
+	  has multiple i2c engines to drive connectivity with a host
+	  infrastructure.
+
+endif
+
+menuconfig ARCH_MOXART
+	bool "MOXA ART SoC"
+	depends on ARCH_MULTI_V4
+	depends on CPU_LITTLE_ENDIAN
+	select CPU_FA526
+	select ARM_DMA_MEM_BUFFERABLE
+	select FARADAY_FTINTC010
+	select FTTMR010_TIMER
+	select GPIOLIB
+	select PHYLIB if NETDEVICES
+	help
+	  Say Y here if you want to run your kernel on hardware with a
+	  MOXA ART SoC.
+	  The MOXA ART SoC is based on a Faraday FA526 ARMv4 32-bit
+	  192 MHz CPU with MMU and 16KB/8KB D/I-cache (UC-7112-LX).
+	  Used on models UC-7101, UC-7112/UC-7110, IA240/IA241, IA3341.
+
+if ARCH_MOXART
+
+config MACH_UC7112LX
+	bool "MOXA UC-7112-LX"
+	depends on ARCH_MOXART
+	help
+	  Say Y here if you intend to run this kernel on a MOXA
+	  UC-7112-LX embedded computer.
+
+endif
+
+config ARCH_NSPIRE
+	bool "TI-NSPIRE based"
+	depends on ARCH_MULTI_V4T
+	depends on CPU_LITTLE_ENDIAN
+	select CPU_ARM926T
+	select GENERIC_IRQ_CHIP
+	select ARM_AMBA
+	select ARM_VIC
+	select ARM_TIMER_SP804
+	select NSPIRE_TIMER
+	select POWER_RESET
+	select POWER_RESET_SYSCON
+	help
+	  This enables support for systems using the TI-NSPIRE CPU
+
+config ARCH_RDA
+	bool "RDA Micro SoCs"
+	depends on ARCH_MULTI_V7
+	select RDA_INTC
+	select RDA_TIMER
+	help
+	  This enables support for the RDA Micro 8810PL SoC family.
+
+menuconfig ARCH_SUNPLUS
+	bool "Sunplus SoCs"
+	depends on ARCH_MULTI_V7
+	help
+	  Support for Sunplus SoC family: SP7021 and succeeding SoC-based systems,
+	  such as the Banana Pi BPI-F2S development board (and derivatives).
+	  (<http://www.sinovoip.com.cn/ecp_view.asp?id=586>)
+	  (<https://tibbo.com/store/plus1.html>)
+
+if ARCH_SUNPLUS
+
+config SOC_SP7021
+	bool "Sunplus SP7021 SoC support"
+	default ARCH_SUNPLUS
+	select HAVE_ARM_ARCH_TIMER
+	select ARM_GIC
+	select ARM_PSCI
+	select PINCTRL
+	select PINCTRL_SPPCTL
+	select SERIAL_SUNPLUS if TTY
+	select SERIAL_SUNPLUS_CONSOLE if TTY
+	help
+	  Support for Sunplus SP7021 SoC. It is based on ARM 4-core
+	  Cortex-A7 with various peripherals (e.g.: I2C, SPI, SDIO,
+	  Ethernet, etc.), FPGA interface,  chip-to-chip bus.
+	  It is designed for industrial control.
+
+endif
+
+config ARCH_UNIPHIER
+	bool "Socionext UniPhier SoCs"
+	depends on ARCH_MULTI_V7
+	select ARCH_HAS_RESET_CONTROLLER
+	select ARM_AMBA
+	select ARM_GLOBAL_TIMER
+	select ARM_GIC
+	select HAVE_ARM_SCU
+	select HAVE_ARM_TWD if SMP
+	select PINCTRL
+	select RESET_CONTROLLER
+	help
+	  Support for UniPhier SoC family developed by Socionext Inc.
+	  (formerly, System LSI Business Division of Panasonic Corporation)