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, 285 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/incomplete-devices.yaml b/Documentation/devicetree/bindings/incomplete-devices.yaml
new file mode 100644
index 000000000..4bb6c0141
--- /dev/null
+++ b/Documentation/devicetree/bindings/incomplete-devices.yaml
@@ -0,0 +1,285 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/incomplete-devices.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Rejected, Legacy or Incomplete Devices
+
+maintainers:
+  - Rob Herring <robh@kernel.org>
+
+description:
+  Some devices will not or should not get a proper Devicetree bindings, but
+  their compatibles are present in Linux drivers for various reasons.
+
+  Examples are devices using ACPI PRP0001 with non-updatable firmware/ACPI
+  tables or old PowerPC platforms without in-tree DTS.
+
+  Following list of devices is an incomplete schema with a goal to pass DT schema
+  checks on undocumented compatibles but also reject any DTS file using such
+  un-approved compatible.
+
+  Usage of any of following compatibles is not allowed in Devicetree sources,
+  even if they come from immutable firmware.
+
+properties:
+  compatible:
+    oneOf:
+      - description:
+          Rejected compatibles in Devicetree, but used in ACPI-based devices
+          with non-updatable firmware/ACPI tables (via ACPI PRP0001)
+        enum:
+          - broadcom,bcm5241
+          - ltr,ltrf216a
+
+      - description: Legacy compatibles used on Macintosh devices
+        enum:
+          - AAPL,3500
+          - AAPL,7500
+          - AAPL,8500
+          - AAPL,9500
+          - AAPL,accelerometer_1
+          - AAPL,e411
+          - AAPL,Gossamer
+          - AAPL,PowerBook1998
+          - AAPL,ShinerESB
+          - adm1030
+          - amd-0137
+          - B5221
+          - bmac+
+          - burgundy
+          - cobalt
+          - cy28508
+          - daca
+          - fcu
+          - gatwick
+          - gmac
+          - heathrow
+          - heathrow-ata
+          - heathrow-media-bay
+          - i2sbus
+          - i2s-modem
+          - iMac
+          - K2-GMAC
+          - k2-i2c
+          - K2-Keylargo
+          - K2-UATA
+          - kauai-ata
+          - Keylargo
+          - keylargo-ata
+          - keylargo-media-bay
+          - lm87cimt
+          - MAC,adm1030
+          - MAC,ds1775
+          - MacRISC
+          - MacRISC2
+          - MacRISC3
+          - MacRISC4
+          - max6690
+          - ohare
+          - ohare-media-bay
+          - ohare-swim3
+          - PowerBook1,1
+          - PowerBook2,1
+          - PowerBook2,2
+          - PowerBook3,1
+          - PowerBook3,2
+          - PowerBook3,3
+          - PowerBook3,4
+          - PowerBook3,5
+          - PowerBook4,1
+          - PowerBook4,2
+          - PowerBook4,3
+          - PowerBook5,1
+          - PowerBook5,2
+          - PowerBook5,3
+          - PowerBook5,4
+          - PowerBook5,5
+          - PowerBook5,6
+          - PowerBook5,7
+          - PowerBook5,8
+          - PowerBook5,9
+          - PowerBook6,3
+          - PowerBook6,5
+          - PowerBook6,7
+          - PowerMac10,1
+          - PowerMac10,2
+          - PowerMac1,1
+          - PowerMac11,2
+          - PowerMac12,1
+          - PowerMac2,1
+          - PowerMac2,2
+          - PowerMac3,1
+          - PowerMac3,4
+          - PowerMac3,5
+          - PowerMac3,6
+          - PowerMac4,1
+          - PowerMac4,2
+          - PowerMac4,4
+          - PowerMac4,5
+          - PowerMac7,2
+          - PowerMac7,3
+          - PowerMac8,1
+          - PowerMac8,2
+          - PowerMac9,1
+          - paddington
+          - RackMac1,1
+          - RackMac1,2
+          - RackMac3,1
+          - screamer
+          - shasta-ata
+          - sms
+          - smu-rpm-fans
+          - smu-sat
+          - smu-sensors
+          - snapper
+          - swim3
+          - tumbler
+          - u3-agp
+          - u3-dart
+          - u3-ht
+          - u4-dart
+          - u4-pcie
+          - U4-pcie
+          - uni-n-i2c
+          - uni-north
+
+      - description: Legacy compatibles used on other PowerPC devices
+        enum:
+          - 1682m-gizmo
+          - 1682m-gpio
+          - 1682m-rng
+          - 1682m-sdc
+          - amcc,ppc440epx-rng
+          - amcc,ppc460ex-bcsr
+          - amcc,ppc460ex-crypto
+          - amcc,ppc460ex-rng
+          - amcc,ppc460sx-crypto
+          - amcc,ppc4xx-crypto
+          - amcc,sata-460ex
+          - CBEA,platform-open-pic
+          - CBEA,platform-spider-pic
+          - direct-mapped
+          - display
+          - gpio-mdio
+          - hawk-bridge
+          - hawk-pci
+          - IBM,CBEA
+          - IBM,lhca
+          - IBM,lhea
+          - IBM,lhea-ethernet
+          - ibm,axon-msic
+          - Momentum,Apache
+          - Momentum,Maple
+          - mai-logic,articia-s
+          - mpc10x-pci
+          - mpc5200b-fec-phy
+          - mpc5200-serial
+          - mpc5200-sram
+          - nintendo,flipper
+          - nintendo,flipper-exi
+          - nintendo,flipper-pi
+          - nintendo,flipper-pic
+          - nintendo,hollywood
+          - nintendo,hollywood-pic
+          - nintendo,latte-exi
+          - nintendo,latte-srnprot
+          - ohci-be
+          - ohci-bigendian
+          - ohci-le
+          - PA6T-1682M
+          - pasemi,1682m-iob
+          - pasemi,localbus
+          - pasemi,localbus-nand
+          - pasemi,nemo
+          - pasemi,pwrficient
+          - pasemi,pwrficient-rng
+          - pasemi,rootbus
+          - pasemi,sdc
+          - soc
+          - sony,ps3
+          - sti,platform-spider-pic
+
+      - description: Legacy compatibles used on SPARC devices
+        enum:
+          - bq4802
+          - ds1287
+          - i2cpcf,8584
+          - isa-m5819p
+          - isa-m5823p
+          - m5819
+          - qcn
+          - sab82532
+          - su
+          - sun4v
+          - SUNW,bbc-beep
+          - SUNW,bbc-i2c
+          - SUNW,CS4231
+          - SUNW,ebus-pic16f747-env
+          - SUNW,kt-cwq
+          - SUNW,kt-mau
+          - SUNW,n2-cwq
+          - SUNW,n2-mau
+          - SUNW,niusl
+          - SUNW,smbus-beep
+          - SUNW,sun4v-console
+          - SUNW,sun4v-pci
+          - SUNW,vf-cwq
+          - SUNW,vf-mau
+
+      - description: Incomplete and/or legacy compatibles for unknown devices
+        enum:
+          - electra-cf
+          - i2cpcf,8584
+          - virtio,uml
+
+      - description: Linux kernel unit tests and sample code
+        enum:
+          - audio-graph-card2-custom-sample
+          - compat1
+          - compat2
+          - compat3
+          - gpio-mockup
+          - gpio-simulator
+          - gpio-virtuser
+          - linux,spi-loopback-test
+          - mailbox-test
+          - regulator-virtual-consumer
+          - test-device
+
+      - description:
+          Devices on MIPS platform, without any DTS users.  These are
+          unlikely to get converted to DT schema.
+        enum:
+          - mti,ranchu
+
+      - description:
+          Devices on PowerPC platform, without any DTS users.  These are
+          unlikely to get converted to DT schema.
+        enum:
+          - fujitsu,coral
+          - fujitsu,lime
+          - fujitsu,MB86276
+          - fujitsu,MB86277
+          - fujitsu,MB86293
+          - fujitsu,MB86294
+          - fujitsu,mint
+          - ibm,axon-msic
+          - ibm,pmemory
+          - ibm,pmemory-v2
+          - ibm,power-rng
+          - ibm,ppc4xx-spi
+          - ibm,sdram-4xx-ddr2
+          - ibm,secureboot
+          - ibm,secureboot-v1
+          - ibm,secureboot-v2
+          - ibm,secvar-backend
+          - sgy,gpio-halt
+          - wrs,epld-localbus
+
+required:
+  - compatible
+  - broken-usage-of-incorrect-compatible
+
+additionalProperties: false