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Date:      Thu, 2 Dec 2010 12:44:51 +0000 (UTC)
From:      Konstantin Belousov <kib@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r216120 - head/sys/fs/procfs
Message-ID:  <201012021244.oB2Cipfm007298@svn.freebsd.org>
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Author: kib
Date: Thu Dec  2 12:44:51 2010
New Revision: 216120
URL: http://svn.freebsd.org/changeset/base/216120

Log:
  For non-stopped threads, td_frame pointer is undefined.  As a
  consequence, fill_regs() and fill_fpregs() access random data, usually
  on the thread kernel stack. Most often the td_frame points to the
  previous frame saved by last kernel entry sequence, but this is not
  guaranteed.
  
  For /proc/<pid>/{regs,fpregs} read access, require the thread to be in
  stopped state. Otherwise, return EBUSY as is done for write case.
  
  Reported and tested by:	pho
  Approved by:	des (procfs maintainer)
  MFC after:	1 week

Modified:
  head/sys/fs/procfs/procfs_fpregs.c
  head/sys/fs/procfs/procfs_regs.c

Modified: head/sys/fs/procfs/procfs_fpregs.c
==============================================================================
--- head/sys/fs/procfs/procfs_fpregs.c	Thu Dec  2 10:46:05 2010	(r216119)
+++ head/sys/fs/procfs/procfs_fpregs.c	Thu Dec  2 12:44:51 2010	(r216120)
@@ -97,6 +97,10 @@ procfs_doprocfpregs(PFS_FILL_ARGS)
 		PROC_UNLOCK(p);
 		return (EPERM);
 	}
+	if (!P_SHOULDSTOP(p)) {
+		PROC_UNLOCK(p);
+		return (EBUSY);
+	}
 
 	/* XXXKSE: */
 	td2 = FIRST_THREAD_IN_PROC(p);

Modified: head/sys/fs/procfs/procfs_regs.c
==============================================================================
--- head/sys/fs/procfs/procfs_regs.c	Thu Dec  2 10:46:05 2010	(r216119)
+++ head/sys/fs/procfs/procfs_regs.c	Thu Dec  2 12:44:51 2010	(r216120)
@@ -97,6 +97,10 @@ procfs_doprocregs(PFS_FILL_ARGS)
 		PROC_UNLOCK(p);
 		return (EPERM);
 	}
+	if (!P_SHOULDSTOP(p)) {
+		PROC_UNLOCK(p);
+		return (EBUSY);
+	}
 
 	/* XXXKSE: */
 	td2 = FIRST_THREAD_IN_PROC(p);

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