From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266676AbUGVCRJ (ORCPT ); Wed, 21 Jul 2004 22:17:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266678AbUGVCRI (ORCPT ); Wed, 21 Jul 2004 22:17:08 -0400 Received: from mail4.speakeasy.net ([216.254.0.204]:9953 "EHLO mail4.speakeasy.net") by vger.kernel.org with ESMTP id S266676AbUGVCQ7 (ORCPT ); Wed, 21 Jul 2004 22:16:59 -0400 Date: Wed, 21 Jul 2004 19:16:52 -0700 Message-Id: <200407220216.i6M2GqEv007394@magilla.sf.frob.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Roland McGrath To: Andi Kleen X-Fcc: ~/Mail/linus Cc: linux-kernel@vger.kernel.org, Andrew Morton Subject: Re: [PATCH] x86-64 singlestep through sigreturn system call In-Reply-To: Andi Kleen's message of Saturday, 17 July 2004 13:12:50 +0200 X-Windows: it could happen to you. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > Hmm, but now the behaviour for 32bit processes is different from the > native 32bit kernel, since 32bit didn't apply any patch so far AFAIK. Well, I was (and am) advocating that Davide's patch for native 32-bit be applied as well. If it is, then my last x86-64 patch covers both 32-bit and 64-bit cases with minimal cruft. In particular, 2.6.8-rc1-mm1 contains Davide's patch and both of my earlier x86-64 patches. I hope Andrew will replace those two patches with the later cleaner single x86-64 patch. If Linus merges that patch of mine and Davide's i386 patch, I will be a happy camper. > If you send me a patch that just changes the behaviour of 64bit > IRET I would apply it. Ok. This is just one line different from the patch I just posted. In 32-bit processes, some ptrace operations will superfluously clear a flag bit that can never be set, rather than test another flag bit to branch around doing it. If/when the native 32-bit behavior fix gets merged in and you want to match it, just remove `if (!test_tsk_thread_flag(child, TIF_IA32))' (which is the same as reverting this patch and applying the earlier one). Thanks, Roland Index: linux-2.6/arch/x86_64/kernel/entry.S =================================================================== RCS file: /home/roland/redhat/bkcvs/linux-2.5/arch/x86_64/kernel/entry.S,v retrieving revision 1.22 diff -b -p -u -r1.22 entry.S --- linux-2.6/arch/x86_64/kernel/entry.S 12 Apr 2004 20:29:12 -0000 1.22 +++ linux-2.6/arch/x86_64/kernel/entry.S 15 Jul 2004 23:45:59 -0000 @@ -297,7 +297,7 @@ int_very_careful: sti SAVE_REST /* Check for syscall exit trace */ - testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),%edx + testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP),%edx jz int_signal pushq %rdi leaq 8(%rsp),%rdi # &ptregs -> arg1 Index: linux-2.6/ptrace.c =================================================================== RCS file: /home/roland/redhat/bkcvs/linux-2.5/arch/x86_64/kernel/ptrace.c,v retrieving revision 1.16 diff -u -b -p -r1.16 ptrace.c --- linux-2.6/ptrace.c 31 May 2004 03:07:42 -0000 1.16 +++ linux-2.6/ptrace.c 22 Jul 2004 00:42:06 -0000 @@ -88,6 +88,7 @@ void ptrace_disable(struct task_struct * { long tmp; + clear_tsk_thread_flag(child, TIF_SINGLESTEP); tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG; put_stack_long(child, EFL_OFFSET, tmp); } @@ -344,6 +345,7 @@ asmlinkage long sys_ptrace(long request, set_tsk_thread_flag(child,TIF_SYSCALL_TRACE); else clear_tsk_thread_flag(child,TIF_SYSCALL_TRACE); + clear_tsk_thread_flag(child, TIF_SINGLESTEP); child->exit_code = data; /* make sure the single step bit is not set. */ tmp = get_stack_long(child, EFL_OFFSET); @@ -395,6 +397,7 @@ asmlinkage long sys_ptrace(long request, ret = 0; if (child->state == TASK_ZOMBIE) /* already dead */ break; + clear_tsk_thread_flag(child, TIF_SINGLESTEP); child->exit_code = SIGKILL; /* make sure the single step bit is not set. */ tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG; @@ -416,6 +419,8 @@ asmlinkage long sys_ptrace(long request, } tmp = get_stack_long(child, EFL_OFFSET) | TRAP_FLAG; put_stack_long(child, EFL_OFFSET, tmp); + if (!test_tsk_thread_flag(child, TIF_IA32)) + set_tsk_thread_flag(child, TIF_SINGLESTEP); child->exit_code = data; /* give it a chance to run. */ wake_up_process(child); @@ -528,7 +533,8 @@ asmlinkage void syscall_trace_leave(stru if (unlikely(current->audit_context)) audit_syscall_exit(current, regs->rax); - if (test_thread_flag(TIF_SYSCALL_TRACE) + if ((test_thread_flag(TIF_SYSCALL_TRACE) + || test_thread_flag(TIF_SINGLESTEP)) && (current->ptrace & PT_PTRACED)) syscall_trace(regs); }