From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions 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) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- .../bindings/counter/fsl,ftm-quaddec.yaml | 36 ++++++++++++ .../bindings/counter/interrupt-counter.yaml | 62 ++++++++++++++++++++ .../bindings/counter/ti,am62-ecap-capture.yaml | 61 ++++++++++++++++++++ .../devicetree/bindings/counter/ti-eqep.yaml | 67 ++++++++++++++++++++++ 4 files changed, 226 insertions(+) create mode 100644 Documentation/devicetree/bindings/counter/fsl,ftm-quaddec.yaml create mode 100644 Documentation/devicetree/bindings/counter/interrupt-counter.yaml create mode 100644 Documentation/devicetree/bindings/counter/ti,am62-ecap-capture.yaml create mode 100644 Documentation/devicetree/bindings/counter/ti-eqep.yaml (limited to 'Documentation/devicetree/bindings/counter') diff --git a/Documentation/devicetree/bindings/counter/fsl,ftm-quaddec.yaml b/Documentation/devicetree/bindings/counter/fsl,ftm-quaddec.yaml new file mode 100644 index 000000000..384ca63b6 --- /dev/null +++ b/Documentation/devicetree/bindings/counter/fsl,ftm-quaddec.yaml @@ -0,0 +1,36 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/counter/fsl,ftm-quaddec.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: FlexTimer Quadrature decoder counter + +description: + Exposes a simple counter for the quadrature decoder mode. + +maintainers: + - Frank Li + +properties: + compatible: + const: fsl,ftm-quaddec + + reg: + maxItems: 1 + + big-endian: true + +required: + - compatible + - reg + +additionalProperties: false + +examples: + - | + counter@29d0000 { + compatible = "fsl,ftm-quaddec"; + reg = <0x29d0000 0x10000>; + big-endian; + }; diff --git a/Documentation/devicetree/bindings/counter/interrupt-counter.yaml b/Documentation/devicetree/bindings/counter/interrupt-counter.yaml new file mode 100644 index 000000000..fd075d104 --- /dev/null +++ b/Documentation/devicetree/bindings/counter/interrupt-counter.yaml @@ -0,0 +1,62 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/counter/interrupt-counter.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Interrupt counter + +maintainers: + - Oleksij Rempel + +description: | + A generic interrupt counter to measure interrupt frequency. It was developed + and used for agricultural devices to measure rotation speed of wheels or + other tools. Since the direction of rotation is not important, only one + signal line is needed. + Interrupts or gpios are required. If both are defined, the interrupt will + take precedence for counting interrupts. + +properties: + compatible: + const: interrupt-counter + + interrupts: + maxItems: 1 + + gpios: + maxItems: 1 + +required: + - compatible + +anyOf: + - required: [ interrupts-extended ] + - required: [ interrupts ] + - required: [ gpios ] + +additionalProperties: false + +examples: + - | + + #include + #include + + counter-0 { + compatible = "interrupt-counter"; + interrupts-extended = <&gpio 0 IRQ_TYPE_EDGE_RISING>; + }; + + counter-1 { + compatible = "interrupt-counter"; + gpios = <&gpio 2 GPIO_ACTIVE_HIGH>; + }; + + counter-2 { + compatible = "interrupt-counter"; + interrupts-extended = <&gpio 2 IRQ_TYPE_EDGE_RISING>; + gpios = <&gpio 2 GPIO_ACTIVE_HIGH>; + }; + +... diff --git a/Documentation/devicetree/bindings/counter/ti,am62-ecap-capture.yaml b/Documentation/devicetree/bindings/counter/ti,am62-ecap-capture.yaml new file mode 100644 index 000000000..4e0b2d2b3 --- /dev/null +++ b/Documentation/devicetree/bindings/counter/ti,am62-ecap-capture.yaml @@ -0,0 +1,61 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/counter/ti,am62-ecap-capture.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Texas Instruments Enhanced Capture (eCAP) Module + +maintainers: + - Julien Panis + +description: | + The eCAP module resources can be used to capture timestamps + on input signal events (falling/rising edges). + +properties: + compatible: + const: ti,am62-ecap-capture + + reg: + maxItems: 1 + + interrupts: + maxItems: 1 + + clocks: + maxItems: 1 + + clock-names: + const: fck + + power-domains: + maxItems: 1 + +required: + - compatible + - reg + - interrupts + - clocks + - clock-names + +additionalProperties: false + +examples: + - | + #include + #include + + soc { + #address-cells = <2>; + #size-cells = <2>; + + capture@23100000 { /* eCAP in capture mode on am62x */ + compatible = "ti,am62-ecap-capture"; + reg = <0x00 0x23100000 0x00 0x100>; + interrupts = ; + power-domains = <&k3_pds 51 TI_SCI_PD_EXCLUSIVE>; + clocks = <&k3_clks 51 0>; + clock-names = "fck"; + }; + }; diff --git a/Documentation/devicetree/bindings/counter/ti-eqep.yaml b/Documentation/devicetree/bindings/counter/ti-eqep.yaml new file mode 100644 index 000000000..c882ab5fc --- /dev/null +++ b/Documentation/devicetree/bindings/counter/ti-eqep.yaml @@ -0,0 +1,67 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/counter/ti-eqep.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Texas Instruments Enhanced Quadrature Encoder Pulse (eQEP) Module + +maintainers: + - David Lechner + +properties: + compatible: + enum: + - ti,am3352-eqep + - ti,am62-eqep + + reg: + maxItems: 1 + + interrupts: + description: The eQEP event interrupt + maxItems: 1 + + clocks: + description: The functional and interface clock that determines the clock + rate for the eQEP peripheral. + maxItems: 1 + + clock-names: + const: sysclkout + + power-domains: + maxItems: 1 + +allOf: + - if: + properties: + compatible: + contains: + enum: + - ti,am62-eqep + then: + properties: + clock-names: false + + required: + - power-domains + +required: + - compatible + - reg + - interrupts + - clocks + +additionalProperties: false + +examples: + - | + eqep0: counter@180 { + compatible = "ti,am3352-eqep"; + reg = <0x180 0x80>; + clocks = <&l4ls_gclk>; + interrupts = <79>; + }; + +... -- cgit v1.3.1