From 35742523e3daa0e59de0c1c3fdd8e5ff52891967 Mon Sep 17 00:00:00 2001 From: Petr Machata Date: Thu, 9 Jan 2014 23:41:50 +0100 Subject: [PATCH] Fix a problem in tracing across fork on PPC64 In order to avoid single-stepping through large portions of the dynamic linker, ltrace remembers at which address the instruction that resolved a PLT slot is. It then puts a breakpoint to this address so that it can fast-forward to that address next time it needs to catch a PLT slot being resolved. When a process is cloned, the pointer to this breakpoint is simply copied over to the new process, instead of being looked up in the new process structures. This patches fixes this. --- sysdeps/linux-gnu/ppc/plt.c | 14 +++++++++++++- 1 files changed, 13 insertions(+), 1 deletions(-) diff --git a/sysdeps/linux-gnu/ppc/plt.c b/sysdeps/linux-gnu/ppc/plt.c index 3ec1397..8715da6 100644 --- a/sysdeps/linux-gnu/ppc/plt.c +++ b/sysdeps/linux-gnu/ppc/plt.c @@ -1,6 +1,6 @@ /* * This file is part of ltrace. - * Copyright (C) 2012,2013 Petr Machata, Red Hat Inc. + * Copyright (C) 2012,2013,2014 Petr Machata, Red Hat Inc. * Copyright (C) 2004,2008,2009 Juan Cespedes * Copyright (C) 2006 Paul Gilliam * @@ -1157,6 +1157,18 @@ int arch_process_clone(struct process *retp, struct process *proc) { retp->arch = proc->arch; + + if (retp->arch.dl_plt_update_bp != NULL) { + /* Point it to the corresponding breakpoint in RETP. + * It must be there, this part of PROC has already + * been cloned to RETP. */ + retp->arch.dl_plt_update_bp + = address2bpstruct(retp, + retp->arch.dl_plt_update_bp->addr); + + assert(retp->arch.dl_plt_update_bp != NULL); + } + return 0; } -- 1.7.6.5