From 804bb7f78fcf94609f31a9d429b82c37d1f1173b Mon Sep 17 00:00:00 2001
From: Kostis Sagonas <kostis@cs.ntua.gr>
Date: Wed, 2 Mar 2011 09:32:09 +0200
Subject: Document exiting and garbage_collecting process statuses

---
 erts/doc/src/erlang.xml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'erts')

diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index 78d58a1e56..c3f06982f5 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -3980,7 +3980,8 @@ os_prompt%</pre>
           <tag><c>{status, Status}</c></tag>
           <item>
             <p><c>Status</c> is the status of the process. <c>Status</c>
-              is <c>waiting</c> (waiting for a message), <c>running</c>,
+              is <c>exiting</c>, <c>garbage_collecting</c>,
+              <c>waiting</c> (for a message), <c>running</c>,
               <c>runnable</c> (ready to run, but another process is
               running), or <c>suspended</c> (suspended on a "busy" port
               or by the <c>erlang:suspend_process/[1,2]</c> BIF).</p>
-- 
cgit v1.2.3


From 22cfda86e15600f8b3622c7ed4101366199e1843 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Fri, 4 Mar 2011 14:10:39 +0100
Subject: erts: Initialize register that may be referenced by garbage
 collection

The call_fun() function in the BEAM emulator is supposed to
to put the fun term in the x register following the actual arguments
and environment for the fun. But if the fun is not loaded and
a call to the error_handler:undefined_lambda/3 function is set up,
the x(3) register will not be initialized.

The lack of initialization is very unlikely to cause a problem
in practice, because all of the following things must happen:

1) An unloaded fun must be called (i.e. the fun must have
been received from another node or from a file or dets table).

2) The process must be scheduled out before the call to the
error_handler:undefined_lambda/3 function can take place.

3) The process must be garbage collected before the process
is scheduled in.

4) The x(3) register must contain a stale cons or box pointer
that happens to point into the the heap of the currently
executing process. (Because of the literal pool, the GC will
never copy anything that is outside of the heap.)

I was not able to write a test case that would force an
emulator crash.
---
 erts/emulator/beam/beam_emu.c | 1 +
 1 file changed, 1 insertion(+)

(limited to 'erts')

diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c
index a4fb454481..e96014c665 100644
--- a/erts/emulator/beam/beam_emu.c
+++ b/erts/emulator/beam/beam_emu.c
@@ -6398,6 +6398,7 @@ call_fun(Process* p,		/* Current process. */
 		reg[0] = module;
 		reg[1] = fun;
 		reg[2] = args;
+		reg[3] = NIL;
 		return ep->address;
 	    }
 	}
-- 
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