Re: [PATCH] tty: fix leakage of -ERESTARTSYS to userland

[Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>]

At Wed, 30 May 2007 18:08:55 -0700 (PDT),
Roland McGrath wrote:
> 
> Aside from typos, I think it should be more clearly and strongly worded.
> 
> "These should never be seen by user programs.  To return one of these
> codes, signal_pending() MUST be set.  Note that ptrace can observe these at
> syscall exit tracing, but they will never be left for the debugged user
> process to see."

Thanks, is that better?

Satoru

---
Add comment for errnos related to restart syscall to avoid the leakage of
them to user programs.

Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>

Index: linux-2.6.22-rc3/include/linux/errno.h
===================================================================
--- linux-2.6.22-rc3.orig/include/linux/errno.h	2007-04-26 12:08:32.000000000 +0900
+++ linux-2.6.22-rc3/include/linux/errno.h	2007-05-31 10:47:40.000000000 +0900
@@ -5,7 +5,12 @@
 
 #ifdef __KERNEL__
 
-/* Should never be seen by user programs */
+/*
+ * These should never be seen by user programs.  To return one of ERESTART*
+ * codes, signal_pending() MUST be set.  Note that ptrace can observe these
+ * at syscall exit tracing, but they will never be left for the debugged user
+ * process to see.
+ */
 #define ERESTARTSYS	512
 #define ERESTARTNOINTR	513
 #define ERESTARTNOHAND	514	/* restart if no handler.. */