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 --- arch/nios2/include/uapi/asm/Kbuild | 4 ++ arch/nios2/include/uapi/asm/byteorder.h | 23 +++++++++ arch/nios2/include/uapi/asm/elf.h | 66 +++++++++++++++++++++++++ arch/nios2/include/uapi/asm/ptrace.h | 84 ++++++++++++++++++++++++++++++++ arch/nios2/include/uapi/asm/sigcontext.h | 31 ++++++++++++ arch/nios2/include/uapi/asm/signal.h | 24 +++++++++ arch/nios2/include/uapi/asm/unistd.h | 19 ++++++++ 7 files changed, 251 insertions(+) create mode 100644 arch/nios2/include/uapi/asm/Kbuild create mode 100644 arch/nios2/include/uapi/asm/byteorder.h create mode 100644 arch/nios2/include/uapi/asm/elf.h create mode 100644 arch/nios2/include/uapi/asm/ptrace.h create mode 100644 arch/nios2/include/uapi/asm/sigcontext.h create mode 100644 arch/nios2/include/uapi/asm/signal.h create mode 100644 arch/nios2/include/uapi/asm/unistd.h (limited to 'arch/nios2/include/uapi') diff --git a/arch/nios2/include/uapi/asm/Kbuild b/arch/nios2/include/uapi/asm/Kbuild new file mode 100644 index 000000000..2501e82a1 --- /dev/null +++ b/arch/nios2/include/uapi/asm/Kbuild @@ -0,0 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0 +syscall-y += unistd_32.h + +generic-y += ucontext.h diff --git a/arch/nios2/include/uapi/asm/byteorder.h b/arch/nios2/include/uapi/asm/byteorder.h new file mode 100644 index 000000000..639007a55 --- /dev/null +++ b/arch/nios2/include/uapi/asm/byteorder.h @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */ +/* + * Copyright (C) 2009 Thomas Chou + * Copyright (C) 2004 Microtronix Datacom Ltd + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#ifndef _ASM_NIOS2_BYTEORDER_H +#define _ASM_NIOS2_BYTEORDER_H + +#include + +#endif diff --git a/arch/nios2/include/uapi/asm/elf.h b/arch/nios2/include/uapi/asm/elf.h new file mode 100644 index 000000000..ab0df71f8 --- /dev/null +++ b/arch/nios2/include/uapi/asm/elf.h @@ -0,0 +1,66 @@ +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */ +/* + * Copyright (C) 2011 Tobias Klauser + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + * + */ + + +#ifndef _UAPI_ASM_NIOS2_ELF_H +#define _UAPI_ASM_NIOS2_ELF_H + +#include + +/* Relocation types */ +#define R_NIOS2_NONE 0 +#define R_NIOS2_S16 1 +#define R_NIOS2_U16 2 +#define R_NIOS2_PCREL16 3 +#define R_NIOS2_CALL26 4 +#define R_NIOS2_IMM5 5 +#define R_NIOS2_CACHE_OPX 6 +#define R_NIOS2_IMM6 7 +#define R_NIOS2_IMM8 8 +#define R_NIOS2_HI16 9 +#define R_NIOS2_LO16 10 +#define R_NIOS2_HIADJ16 11 +#define R_NIOS2_BFD_RELOC_32 12 +#define R_NIOS2_BFD_RELOC_16 13 +#define R_NIOS2_BFD_RELOC_8 14 +#define R_NIOS2_GPREL 15 +#define R_NIOS2_GNU_VTINHERIT 16 +#define R_NIOS2_GNU_VTENTRY 17 +#define R_NIOS2_UJMP 18 +#define R_NIOS2_CJMP 19 +#define R_NIOS2_CALLR 20 +#define R_NIOS2_ALIGN 21 +/* Keep this the last entry. */ +#define R_NIOS2_NUM 22 + +typedef unsigned long elf_greg_t; + +#define ELF_NGREG 49 +typedef elf_greg_t elf_gregset_t[ELF_NGREG]; + +typedef unsigned long elf_fpregset_t; + +/* + * These are used to set parameters in the core dumps. + */ +#define ELF_CLASS ELFCLASS32 +#define ELF_DATA ELFDATA2LSB +#define ELF_ARCH EM_ALTERA_NIOS2 + +#endif /* _UAPI_ASM_NIOS2_ELF_H */ diff --git a/arch/nios2/include/uapi/asm/ptrace.h b/arch/nios2/include/uapi/asm/ptrace.h new file mode 100644 index 000000000..1298db9f0 --- /dev/null +++ b/arch/nios2/include/uapi/asm/ptrace.h @@ -0,0 +1,84 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Copyright (C) 2010 Tobias Klauser + * Copyright (C) 2004 Microtronix Datacom Ltd + * + * based on m68k asm/processor.h + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#ifndef _UAPI_ASM_NIOS2_PTRACE_H +#define _UAPI_ASM_NIOS2_PTRACE_H + +#ifndef __ASSEMBLER__ + +#include + +/* + * Register numbers used by 'ptrace' system call interface. + */ + +/* GP registers */ +#define PTR_R0 0 +#define PTR_R1 1 +#define PTR_R2 2 +#define PTR_R3 3 +#define PTR_R4 4 +#define PTR_R5 5 +#define PTR_R6 6 +#define PTR_R7 7 +#define PTR_R8 8 +#define PTR_R9 9 +#define PTR_R10 10 +#define PTR_R11 11 +#define PTR_R12 12 +#define PTR_R13 13 +#define PTR_R14 14 +#define PTR_R15 15 +#define PTR_R16 16 +#define PTR_R17 17 +#define PTR_R18 18 +#define PTR_R19 19 +#define PTR_R20 20 +#define PTR_R21 21 +#define PTR_R22 22 +#define PTR_R23 23 +#define PTR_R24 24 +#define PTR_R25 25 +#define PTR_GP 26 +#define PTR_SP 27 +#define PTR_FP 28 +#define PTR_EA 29 +#define PTR_BA 30 +#define PTR_RA 31 +/* Control registers */ +#define PTR_PC 32 +#define PTR_STATUS 33 +#define PTR_ESTATUS 34 +#define PTR_BSTATUS 35 +#define PTR_IENABLE 36 +#define PTR_IPENDING 37 +#define PTR_CPUID 38 +#define PTR_CTL6 39 +#define PTR_EXCEPTION 40 +#define PTR_PTEADDR 41 +#define PTR_TLBACC 42 +#define PTR_TLBMISC 43 +#define PTR_ECCINJ 44 +#define PTR_BADADDR 45 +#define PTR_CONFIG 46 +#define PTR_MPUBASE 47 +#define PTR_MPUACC 48 + +#define NUM_PTRACE_REG (PTR_MPUACC + 1) + +/* User structures for general purpose registers. */ +struct user_pt_regs { + __u32 regs[49]; +}; + +#endif /* __ASSEMBLER__ */ +#endif /* _UAPI_ASM_NIOS2_PTRACE_H */ diff --git a/arch/nios2/include/uapi/asm/sigcontext.h b/arch/nios2/include/uapi/asm/sigcontext.h new file mode 100644 index 000000000..204ae3475 --- /dev/null +++ b/arch/nios2/include/uapi/asm/sigcontext.h @@ -0,0 +1,31 @@ +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */ +/* + * Copyright (C) 2004, Microtronix Datacom Ltd. + * + * All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for more + * details. + */ + +#ifndef _UAPI__ASM_SIGCONTEXT_H +#define _UAPI__ASM_SIGCONTEXT_H + +#include + +#define MCONTEXT_VERSION 2 + +struct sigcontext { + int version; + unsigned long gregs[32]; +}; + +#endif diff --git a/arch/nios2/include/uapi/asm/signal.h b/arch/nios2/include/uapi/asm/signal.h new file mode 100644 index 000000000..b0d983068 --- /dev/null +++ b/arch/nios2/include/uapi/asm/signal.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Copyright Altera Corporation (C) 2013. All rights reserved + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see . + * + */ +#ifndef _ASM_NIOS2_SIGNAL_H +#define _ASM_NIOS2_SIGNAL_H + +#define SA_RESTORER 0x04000000 +#include + +#endif /* _ASM_NIOS2_SIGNAL_H */ diff --git a/arch/nios2/include/uapi/asm/unistd.h b/arch/nios2/include/uapi/asm/unistd.h new file mode 100644 index 000000000..1f0e0f553 --- /dev/null +++ b/arch/nios2/include/uapi/asm/unistd.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Copyright (C) 2013 Altera Corporation + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see . + * + */ + +#include -- cgit v1.3.1