Re: [PATCH] riscv: tracing: Fix __write_overflow_field in ftrace_partial_regs()
From: Alexandre Ghiti <alex@ghiti.fr>
Date: 2025-02-25 08:36:12
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linux-riscv, lkml
Hi Charlie, On 25/02/2025 03:42, Charlie Jenkins wrote:
The size of ®s->a0 is unknown, causing the error: ../include/linux/fortify-string.h:571:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
I can't reproduce this warning with gcc and llvm, even when setting by hand -Wattribute-warning when compiling bpf_trace.c (which is the user of ftrace_partial_regs()). Which toolchain did you use? Thanks, Alex
quoted hunk ↗ jump to hunk
Fix this by wrapping the required registers in pt_regs with struct_group() and reference the group when doing the offending memcpy(). Signed-off-by: Charlie Jenkins <redacted> --- arch/riscv/include/asm/ftrace.h | 2 +- arch/riscv/include/asm/ptrace.h | 18 ++++++++++-------- 2 files changed, 11 insertions(+), 9 deletions(-)diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h index c4721ce44ca474654b37b3d51bc0a63d46bc1eff..ec6db1162021fbf4fa48fc87e7984266040aa7d9 100644 --- a/arch/riscv/include/asm/ftrace.h +++ b/arch/riscv/include/asm/ftrace.h@@ -207,7 +207,7 @@ ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs *regs) { struct __arch_ftrace_regs *afregs = arch_ftrace_regs(fregs); - memcpy(®s->a0, afregs->args, sizeof(afregs->args)); + memcpy(®s->a_regs, afregs->args, sizeof(afregs->args)); regs->epc = afregs->epc; regs->ra = afregs->ra; regs->sp = afregs->sp;diff --git a/arch/riscv/include/asm/ptrace.h b/arch/riscv/include/asm/ptrace.h index b5b0adcc85c18e15c156de11172a5d7f03ada037..2910231977cb71dac3cc42f2dc32590284204057 100644 --- a/arch/riscv/include/asm/ptrace.h +++ b/arch/riscv/include/asm/ptrace.h@@ -23,14 +23,16 @@ struct pt_regs { unsigned long t2; unsigned long s0; unsigned long s1; - unsigned long a0; - unsigned long a1; - unsigned long a2; - unsigned long a3; - unsigned long a4; - unsigned long a5; - unsigned long a6; - unsigned long a7; + struct_group(a_regs, + unsigned long a0; + unsigned long a1; + unsigned long a2; + unsigned long a3; + unsigned long a4; + unsigned long a5; + unsigned long a6; + unsigned long a7; + ); unsigned long s2; unsigned long s3; unsigned long s4;--- base-commit: d082ecbc71e9e0bf49883ee4afd435a77a5101b6 change-id: 20250224-fix_ftrace_partial_regs-eddaf4a7e5ed