From cc6c4d81d6ad007ef66c07f35b0ba8f50f3a235a Mon Sep 17 00:00:00 2001 From: Vamshi K Sthambamkadi Date: Fri, 28 Aug 2020 17:02:46 +0530 Subject: [PATCH] tracing/kprobes, x86/ptrace: Fix regs argument order for i386 commit 2356bb4b8221d7dc8c7beb810418122ed90254c9 upstream. On i386, the order of parameters passed on regs is eax,edx,and ecx (as per regparm(3) calling conventions). Change the mapping in regs_get_kernel_argument(), so that arg1=ax arg2=dx, and arg3=cx. Running the selftests testcase kprobes_args_use.tc shows the result as passed. Fixes: 3c88ee194c28 ("x86: ptrace: Add function argument access API") Signed-off-by: Vamshi K Sthambamkadi Signed-off-by: Borislav Petkov Acked-by: Masami Hiramatsu Acked-by: Peter Zijlstra (Intel) Cc: Link: https://lkml.kernel.org/r/20200828113242.GA1424@cosmos Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/ptrace.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index 332eb3525867..902be2e6e96c 100644 --- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -309,8 +309,8 @@ static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs, static const unsigned int argument_offs[] = { #ifdef __i386__ offsetof(struct pt_regs, ax), - offsetof(struct pt_regs, cx), offsetof(struct pt_regs, dx), + offsetof(struct pt_regs, cx), #define NR_REG_ARGUMENTS 3 #else offsetof(struct pt_regs, di),