[PATCH 2/2] ptrace: don't send SIGTRAP on exec if SEIZED

[Oleg Nesterov <oleg@redhat.com>]

ptrace_event(PTRACE_EVENT_EXEC) sends SIGTRAP if PT_TRACE_EXEC is
not set. This is because this SIGTRAP predates PTRACE_O_TRACEEXEC
option, we do not need/want this with PT_SEIZED which can set the
options during attach.

Suggested-by: Pedro Alves <palves@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
 include/linux/ptrace.h |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 6dffe18..407c678 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -194,9 +194,10 @@ static inline void ptrace_event(int event, unsigned long message)
 	if (unlikely(ptrace_event_enabled(current, event))) {
 		current->ptrace_message = message;
 		ptrace_notify((event << 8) | SIGTRAP);
-	} else if (event == PTRACE_EVENT_EXEC && unlikely(current->ptrace)) {
+	} else if (event == PTRACE_EVENT_EXEC) {
 		/* legacy EXEC report via SIGTRAP */
-		send_sig(SIGTRAP, current, 0);
+		if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED)
+			send_sig(SIGTRAP, current, 0);
 	}
 }
 
-- 
1.5.5.1