NetBSD Problem Report #3471
Received: (qmail-queue invoked from smtpd); 10 Apr 1997 05:15:44 -0000
Message-Id: <199704100522.WAA00482@epsilon.teraflop.com>
Date: Wed, 9 Apr 1997 22:22:51 -0700 (PDT)
From: Ross Harvey <ross@teraflop.com>
Reply-To: ross@teraflop.com
To: gnats-bugs@gnats.netbsd.org
Subject: fix for kernel crash (mount_null) in netbsd/alpha
X-Send-Pr-Version: 3.95
>Number: 3471
>Category: port-alpha
>Synopsis: mount_null crashes kernel because of unimplemented gcc debug stmt
>Confidential: no
>Severity: critical
>Priority: medium
>Responsible: gnats-admin
>State: closed
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Wed Apr 09 22:20:01 +0000 1997
>Closed-Date: Thu Apr 10 05:34:18 +0000 1997
>Last-Modified: Wed Sep 05 00:50:12 +0000 2001
>Originator: Ross Harvey
>Release: apparently in all releases
>Organization:
Avalon Computer Systems, Inc.
>Environment:
netbsd alpha, bug is actually in gcc alpha target logic
System: NetBSD epsilon.teraflop.com 1.2D NetBSD 1.2D (e) #15: Wed Apr 9 21:12:42 PDT 1997 ross@epsilon.ghs.com:/bsd/ross/e alpha
>Description:
Diagnostic statements in miscfs/nullfs/null_vnops.c (lines
555 & 556) call RETURN_PC(x), this is apparently the only
place in the kernel where the gcc builtin
__builtin_return_address(frameno)
is called. It _might_ work with frameno 0 but not with frameno 1.
>How-To-Repeat:
Easy. % cd /tmp
% mkdir a b a/a b/b
% sync
% mount_null a/a b/b
<<boom, mmu fault on *(NULL) dereference>>
>Fix:
Kill the macro on alpha, maybe on every target...
Apply patch in /sys/miscfs/nullfs/
--- /sys/miscfs/nullfs/null.h Sat May 18 04:36:29 1996
+++ null.h Wed Apr 9 21:12:04 1997
@@ -64,7 +64,7 @@
#endif
};
-#if !defined(__GNUC__) || __GNUC__ < 2 || \
+#if defined(__alpha__) || !defined(__GNUC__) || __GNUC__ < 2 || \
(__GNUC__ == 2 && __GNUC_MINOR__ < 5)
#define RETURN_PC(frameno) (void *)0
#else
>Release-Note:
>Audit-Trail:
State-Changed-From-To: open->closed
State-Changed-By: cgd
State-Changed-When: Wed Apr 9 22:34:18 PDT 1997
State-Changed-Why:
patch applied. thanks!
>Unformatted:
(Contact us)
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