[merged] ptrace-x86-change-syscall_trace_leave-to-rely-on-tracehook-when-stepping.patch removed from -mm tree

[akpm@linux-foundation.org]

The patch titled
     ptrace: x86: change syscall_trace_leave() to rely on tracehook when stepping
has been removed from the -mm tree.  Its filename was
     ptrace-x86-change-syscall_trace_leave-to-rely-on-tracehook-when-stepping.patch

This patch was dropped because it was merged into mainline or a subsystem tree

The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/

------------------------------------------------------
Subject: ptrace: x86: change syscall_trace_leave() to rely on tracehook when stepping
From: Oleg Nesterov <oleg@redhat.com>

Suggested by Roland.

Unlike powepc, x86 always calls tracehook_report_syscall_exit(step) with
step = 0, and sends the trap by hand.

This results in unnecessary SIGTRAP when PTRACE_SINGLESTEP follows the
syscall-exit stop.

Change syscall_trace_leave() to pass the correct "step" argument to
tracehook and remove the send_sigtrap() logic.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: <linux-arch@vger.kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/x86/kernel/ptrace.c |   21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff -puN arch/x86/kernel/ptrace.c~ptrace-x86-change-syscall_trace_leave-to-rely-on-tracehook-when-stepping arch/x86/kernel/ptrace.c
--- a/arch/x86/kernel/ptrace.c~ptrace-x86-change-syscall_trace_leave-to-rely-on-tracehook-when-stepping
+++ a/arch/x86/kernel/ptrace.c
@@ -1767,29 +1767,22 @@ asmregparm long syscall_trace_enter(stru
 
 asmregparm void syscall_trace_leave(struct pt_regs *regs)
 {
+	bool step;
+
 	if (unlikely(current->audit_context))
 		audit_syscall_exit(AUDITSC_RESULT(regs->ax), regs->ax);
 
 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 		trace_sys_exit(regs, regs->ax);
 
-	if (test_thread_flag(TIF_SYSCALL_TRACE))
-		tracehook_report_syscall_exit(regs, 0);
-
 	/*
 	 * If TIF_SYSCALL_EMU is set, we only get here because of
 	 * TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP).
 	 * We already reported this syscall instruction in
-	 * syscall_trace_enter(), so don't do any more now.
-	 */
-	if (unlikely(test_thread_flag(TIF_SYSCALL_EMU)))
-		return;
-
-	/*
-	 * If we are single-stepping, synthesize a trap to follow the
-	 * system call instruction.
+	 * syscall_trace_enter().
 	 */
-	if (test_thread_flag(TIF_SINGLESTEP) &&
-	    tracehook_consider_fatal_signal(current, SIGTRAP))
-		send_sigtrap(current, regs, 0, TRAP_BRKPT);
+	step = unlikely(test_thread_flag(TIF_SINGLESTEP)) &&
+			!test_thread_flag(TIF_SYSCALL_EMU);
+	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
+		tracehook_report_syscall_exit(regs, step);
 }
_

Patches currently in -mm which might be from oleg@redhat.com are

origin.patch
do_wait-optimization-do-not-place-sub-threads-on-task_struct-children-list.patch
mm-introduce-coredump-parameter-structure.patch
linux-next.patch
posix-cpu-timers-reset-expire-cache-when-no-timer-is-running.patch