Messages in this thread Patch in this message | | | Date | Wed, 21 Jul 2004 19:16:52 -0700 | From | Roland McGrath <> | Subject | Re: [PATCH] x86-64 singlestep through sigreturn system call |
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> 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); } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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