arch/ && tracehook_report_syscall_xxx()

From: Oleg Nesterov
Date: Mon Apr 27 2009 - 14:09:01 EST


We have a lot of code like arch/alpha/kernel/ptrace.c:syscall_trace()
in arch/ and I can't see how to convert them to use tracehooks.

The first problem, we don't know which hook should be called, there is
no entry/exit argument.

Still, I think it is better to change this code right now, and call
ptrace_report_syscall() directly.

But, the second problem, there is no "struct pt_regs *". What do you
think about the patch below?

However. I can't imagine how ptrace_report_syscall(regs) can actually
use "regs". Perhaps we can remove this argument?

Or what else do you think?

Hmm... and I can't understand how to change
arch/mn10300/kernel/ptrace.c:do_syscall_trace(), it does something
strange with TIF_SINGLESTEP. (maintainers cc'ed).

Oleg.

--- PTRACE/arch/alpha/kernel/ptrace.c~1_alpha 2009-04-06 00:03:35.000000000 +0200
+++ PTRACE/arch/alpha/kernel/ptrace.c 2009-04-27 19:11:50.000000000 +0200
@@ -11,6 +11,7 @@
#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
+#include <linux/tracehook.h>
#include <linux/user.h>
#include <linux/slab.h>
#include <linux/security.h>
@@ -354,20 +355,6 @@ syscall_trace(void)
{
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return;
- if (!(current->ptrace & PT_PTRACED))
- return;
- /* The 0x80 provides a way for the tracing parent to distinguish
- between a syscall stop and SIGTRAP delivery */
- ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
- ? 0x80 : 0));

- /*
- * This isn't the same as continuing with a signal, but it will do
- * for normal use. strace only continues with a signal if the
- * stopping signal is not SIGTRAP. -brl
- */
- if (current->exit_code) {
- send_sig(current->exit_code, current, 1);
- current->exit_code = 0;
- }
+ ptrace_report_syscall(NULL);
}

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