From: Vamshi K Sthambamkadi vamshi.k.sthambamkadi@gmail.com
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 vamshi.k.sthambamkadi@gmail.com Signed-off-by: Borislav Petkov bp@suse.de Acked-by: Masami Hiramatsu mhiramat@kernel.org Acked-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20200828113242.GA1424@cosmos Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/include/asm/ptrace.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -309,8 +309,8 @@ static inline unsigned long regs_get_ker 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),