Fix in 2.0.32 for debugging of multithreaded processes

Philip Gladstone (philip@raptor.com)
Wed, 10 Dec 1997 12:08:24 -0500

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The attached (small) patch to kernel/exit.c allows gdb and strace
to be used on the threads of a multithreaded process. This is
not the end of the the problems, but a big step forward.

I suspect that the same patch could be applied to the 2.1.x
series as well.

Philip

-- 
Philip Gladstone                           +1 781 487 7700
Raptor Systems, Waltham, MA         http://www.raptor.com/
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--- linux/kernel/exit.c.orig	Wed Nov 19 16:33:22 1997
+++ linux/kernel/exit.c	Wed Nov 19 16:36:38 1997
@@ -639,9 +639,14 @@
 			if (p->pgrp != -pid)
 				continue;
 		}
-		/* wait for cloned processes iff the __WCLONE flag is set */
-		if ((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
-			continue;
+		/* If you are tracing a process, then you don't need to get the
+		 * WCLONE bit right -- useful for strace and gdb
+		 */
+		if (!(p->flags & (PF_PTRACED|PF_TRACESYS))) {
+			/* wait for cloned processes iff the __WCLONE flag is set */
+			if ((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
+				continue;
+		}
 		flag = 1;
 		switch (p->state) {
 			case TASK_STOPPED:


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