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/microblaze/include/uapi/asm/Kbuild | 3 + arch/microblaze/include/uapi/asm/auxvec.h | 2 + arch/microblaze/include/uapi/asm/byteorder.h | 11 +++ arch/microblaze/include/uapi/asm/elf.h | 123 +++++++++++++++++++++++++ arch/microblaze/include/uapi/asm/posix_types.h | 10 ++ arch/microblaze/include/uapi/asm/ptrace.h | 73 +++++++++++++++ arch/microblaze/include/uapi/asm/setup.h | 17 ++++ arch/microblaze/include/uapi/asm/sigcontext.h | 21 +++++ arch/microblaze/include/uapi/asm/unistd.h | 16 ++++ 9 files changed, 276 insertions(+) create mode 100644 arch/microblaze/include/uapi/asm/Kbuild create mode 100644 arch/microblaze/include/uapi/asm/auxvec.h create mode 100644 arch/microblaze/include/uapi/asm/byteorder.h create mode 100644 arch/microblaze/include/uapi/asm/elf.h create mode 100644 arch/microblaze/include/uapi/asm/posix_types.h create mode 100644 arch/microblaze/include/uapi/asm/ptrace.h create mode 100644 arch/microblaze/include/uapi/asm/setup.h create mode 100644 arch/microblaze/include/uapi/asm/sigcontext.h create mode 100644 arch/microblaze/include/uapi/asm/unistd.h (limited to 'arch/microblaze/include/uapi') diff --git a/arch/microblaze/include/uapi/asm/Kbuild b/arch/microblaze/include/uapi/asm/Kbuild new file mode 100644 index 000000000..da95c5a03 --- /dev/null +++ b/arch/microblaze/include/uapi/asm/Kbuild @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0 +generated-y += unistd_32.h +generic-y += ucontext.h diff --git a/arch/microblaze/include/uapi/asm/auxvec.h b/arch/microblaze/include/uapi/asm/auxvec.h new file mode 100644 index 000000000..93dd07bd0 --- /dev/null +++ b/arch/microblaze/include/uapi/asm/auxvec.h @@ -0,0 +1,2 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ + diff --git a/arch/microblaze/include/uapi/asm/byteorder.h b/arch/microblaze/include/uapi/asm/byteorder.h new file mode 100644 index 000000000..763660169 --- /dev/null +++ b/arch/microblaze/include/uapi/asm/byteorder.h @@ -0,0 +1,11 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef _ASM_MICROBLAZE_BYTEORDER_H +#define _ASM_MICROBLAZE_BYTEORDER_H + +#ifdef __MICROBLAZEEL__ +#include +#else +#include +#endif + +#endif /* _ASM_MICROBLAZE_BYTEORDER_H */ diff --git a/arch/microblaze/include/uapi/asm/elf.h b/arch/microblaze/include/uapi/asm/elf.h new file mode 100644 index 000000000..6b656de29 --- /dev/null +++ b/arch/microblaze/include/uapi/asm/elf.h @@ -0,0 +1,123 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Copyright (C) 2008-2009 Michal Simek + * Copyright (C) 2008-2009 PetaLogix + * Copyright (C) 2006 Atmark Techno, Inc. + * + * 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_MICROBLAZE_ELF_H +#define _UAPI_ASM_MICROBLAZE_ELF_H + +#include + +/* + * Note there is no "official" ELF designation for Microblaze. + * I've snaffled the value from the microblaze binutils source code + * /binutils/microblaze/include/elf/microblaze.h + */ +#define EM_MICROBLAZE_OLD 0xbaab +#define ELF_ARCH EM_MICROBLAZE + +/* + * This is used to ensure we don't load something for the wrong architecture. + */ +#define elf_check_arch(x) ((x)->e_machine == EM_MICROBLAZE \ + || (x)->e_machine == EM_MICROBLAZE_OLD) + +/* + * These are used to set parameters in the core dumps. + */ +#define ELF_CLASS ELFCLASS32 + +#ifndef __uClinux__ + +/* + * ELF register definitions.. + */ + +#include +#include + +#ifndef ELF_GREG_T +#define ELF_GREG_T +typedef unsigned long elf_greg_t; +#endif + +#ifndef ELF_NGREG +#define ELF_NGREG (sizeof(struct pt_regs) / sizeof(elf_greg_t)) +#endif + +#ifndef ELF_GREGSET_T +#define ELF_GREGSET_T +typedef elf_greg_t elf_gregset_t[ELF_NGREG]; +#endif + +#ifndef ELF_FPREGSET_T +#define ELF_FPREGSET_T + +/* TBD */ +#define ELF_NFPREG 33 /* includes fsr */ +typedef unsigned long elf_fpreg_t; +typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG]; + +/* typedef struct user_fpu_struct elf_fpregset_t; */ +#endif + +/* This is the location that an ET_DYN program is loaded if exec'ed. Typical + * use of this is to invoke "./ld.so someprog" to test out a new version of + * the loader. We need to make sure that it is out of the way of the program + * that it will "exec", and that there is sufficient room for the brk. + */ + +#define ELF_ET_DYN_BASE (0x08000000) + +#ifdef __MICROBLAZEEL__ +#define ELF_DATA ELFDATA2LSB +#else +#define ELF_DATA ELFDATA2MSB +#endif + +#define ELF_EXEC_PAGESIZE PAGE_SIZE + + +#define ELF_CORE_COPY_REGS(_dest, _regs) \ + memcpy((char *) &_dest, (char *) _regs, \ + sizeof(struct pt_regs)); + +/* This yields a mask that user programs can use to figure out what + * instruction set this CPU supports. This could be done in user space, + * but it's not easy, and we've already done it here. + */ +#define ELF_HWCAP (0) + +/* This yields a string that ld.so will use to load implementation + * specific libraries for optimization. This is more specific in + * intent than poking at uname or /proc/cpuinfo. + + * For the moment, we have only optimizations for the Intel generations, + * but that could change... + */ +#define ELF_PLATFORM (NULL) + +/* Added _f parameter. Is this definition correct: TBD */ +#define ELF_PLAT_INIT(_r, _f) \ +do { \ + _r->r0 = _r->r1 = _r->r2 = _r->r3 = \ + _r->r4 = _r->r5 = _r->r6 = _r->r7 = \ + _r->r8 = _r->r9 = _r->r10 = _r->r11 = \ + _r->r12 = _r->r13 = _r->r14 = _r->r15 = \ + _r->r16 = _r->r17 = _r->r18 = _r->r19 = \ + _r->r20 = _r->r21 = _r->r22 = _r->r23 = \ + _r->r24 = _r->r25 = _r->r26 = _r->r27 = \ + _r->r28 = _r->r29 = _r->r30 = _r->r31 = \ + 0; \ +} while (0) + + +#endif /* __uClinux__ */ + +#endif /* _UAPI_ASM_MICROBLAZE_ELF_H */ diff --git a/arch/microblaze/include/uapi/asm/posix_types.h b/arch/microblaze/include/uapi/asm/posix_types.h new file mode 100644 index 000000000..f3249da69 --- /dev/null +++ b/arch/microblaze/include/uapi/asm/posix_types.h @@ -0,0 +1,10 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef _ASM_MICROBLAZE_POSIX_TYPES_H +#define _ASM_MICROBLAZE_POSIX_TYPES_H + +typedef unsigned short __kernel_mode_t; +#define __kernel_mode_t __kernel_mode_t + +#include + +#endif /* _ASM_MICROBLAZE_POSIX_TYPES_H */ diff --git a/arch/microblaze/include/uapi/asm/ptrace.h b/arch/microblaze/include/uapi/asm/ptrace.h new file mode 100644 index 000000000..8039957a1 --- /dev/null +++ b/arch/microblaze/include/uapi/asm/ptrace.h @@ -0,0 +1,73 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Copyright (C) 2006 Atmark Techno, Inc. + * + * 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_MICROBLAZE_PTRACE_H +#define _UAPI_ASM_MICROBLAZE_PTRACE_H + +#ifndef __ASSEMBLER__ + +typedef unsigned long microblaze_reg_t; + +struct pt_regs { + microblaze_reg_t r0; + microblaze_reg_t r1; + microblaze_reg_t r2; + microblaze_reg_t r3; + microblaze_reg_t r4; + microblaze_reg_t r5; + microblaze_reg_t r6; + microblaze_reg_t r7; + microblaze_reg_t r8; + microblaze_reg_t r9; + microblaze_reg_t r10; + microblaze_reg_t r11; + microblaze_reg_t r12; + microblaze_reg_t r13; + microblaze_reg_t r14; + microblaze_reg_t r15; + microblaze_reg_t r16; + microblaze_reg_t r17; + microblaze_reg_t r18; + microblaze_reg_t r19; + microblaze_reg_t r20; + microblaze_reg_t r21; + microblaze_reg_t r22; + microblaze_reg_t r23; + microblaze_reg_t r24; + microblaze_reg_t r25; + microblaze_reg_t r26; + microblaze_reg_t r27; + microblaze_reg_t r28; + microblaze_reg_t r29; + microblaze_reg_t r30; + microblaze_reg_t r31; + microblaze_reg_t pc; + microblaze_reg_t msr; + microblaze_reg_t ear; + microblaze_reg_t esr; + microblaze_reg_t fsr; + int pt_mode; +}; + +#ifndef __KERNEL__ + +/* pt_regs offsets used by gdbserver etc in ptrace syscalls */ +#define PT_GPR(n) ((n) * sizeof(microblaze_reg_t)) +#define PT_PC (32 * sizeof(microblaze_reg_t)) +#define PT_MSR (33 * sizeof(microblaze_reg_t)) +#define PT_EAR (34 * sizeof(microblaze_reg_t)) +#define PT_ESR (35 * sizeof(microblaze_reg_t)) +#define PT_FSR (36 * sizeof(microblaze_reg_t)) +#define PT_KERNEL_MODE (37 * sizeof(microblaze_reg_t)) + +#endif /* __KERNEL */ + +#endif /* __ASSEMBLER__ */ + +#endif /* _UAPI_ASM_MICROBLAZE_PTRACE_H */ diff --git a/arch/microblaze/include/uapi/asm/setup.h b/arch/microblaze/include/uapi/asm/setup.h new file mode 100644 index 000000000..16c56807f --- /dev/null +++ b/arch/microblaze/include/uapi/asm/setup.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Copyright (C) 2007-2009 Michal Simek + * Copyright (C) 2007-2009 PetaLogix + * Copyright (C) 2006 Atmark Techno, Inc. + * + * 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_MICROBLAZE_SETUP_H +#define _UAPI_ASM_MICROBLAZE_SETUP_H + +#define COMMAND_LINE_SIZE 256 + +#endif /* _UAPI_ASM_MICROBLAZE_SETUP_H */ diff --git a/arch/microblaze/include/uapi/asm/sigcontext.h b/arch/microblaze/include/uapi/asm/sigcontext.h new file mode 100644 index 000000000..47eb2e211 --- /dev/null +++ b/arch/microblaze/include/uapi/asm/sigcontext.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Copyright (C) 2006 Atmark Techno, Inc. + * + * 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 _ASM_MICROBLAZE_SIGCONTEXT_H +#define _ASM_MICROBLAZE_SIGCONTEXT_H + +/* FIXME should be linux/ptrace.h */ +#include + +struct sigcontext { + struct pt_regs regs; + unsigned long oldmask; +}; + +#endif /* _ASM_MICROBLAZE_SIGCONTEXT_H */ diff --git a/arch/microblaze/include/uapi/asm/unistd.h b/arch/microblaze/include/uapi/asm/unistd.h new file mode 100644 index 000000000..3f2d7cb68 --- /dev/null +++ b/arch/microblaze/include/uapi/asm/unistd.h @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Copyright (C) 2007-2008 Michal Simek + * Copyright (C) 2006 Atmark Techno, Inc. + * + * 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_MICROBLAZE_UNISTD_H +#define _UAPI_ASM_MICROBLAZE_UNISTD_H + +#include + +#endif /* _UAPI_ASM_MICROBLAZE_UNISTD_H */ -- cgit v1.3.1