NetBSD Problem Report #45421

From woods@once.weird.com  Tue Oct  4 18:37:52 2011
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Date: Tue, 4 Oct 2011 11:37:48 -0700 (PDT)
From: "Greg A. Woods" <woods@planix.com>
Sender: "Greg A. Woods" <woods@once.weird.com>
Reply-To: "Greg A. Woods" <woods@planix.com>
To: gnats-bugs@gnats.NetBSD.org
Subject: kernel should log and inform user when it uses SIGKILL because of RLIMIT_CPU
X-Send-Pr-Version: 3.95

>Number:         45421
>Category:       kern
>Synopsis:       kernel should log and inform user when it uses SIGKILL because of RLIMIT_CPU
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          closed
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Oct 04 18:40:00 +0000 2011
>Closed-Date:    Wed Oct 05 13:54:52 +0000 2011
>Last-Modified:  Wed Oct 05 13:54:52 +0000 2011
>Originator:     Greg A. Woods
>Release:        NetBSD-current 2011/10/04
>Organization:
Planix, Inc.; Kelowna, BC; Canada
>Environment:
System: NetBSD
Architecture: all
Machine: all
>Description:

	the kernel should log, and inform the user, when it uses SIGKILL
	to terminate a process because it has exceeded RLIMIT_CPU.

	also, fix a nearby errant use of printf() instead of log().

>How-To-Repeat:

	try to make actual use of CPU limits without confusing and
	angering users

>Fix:

Index: sys/kern/kern_synch.c
===================================================================
RCS file: /cvs/master/m-NetBSD/main/src/sys/kern/kern_synch.c,v
retrieving revision 1.291
diff -u -r1.291 kern_synch.c
--- sys/kern/kern_synch.c	27 Sep 2011 01:02:38 -0000	1.291
+++ sys/kern/kern_synch.c	4 Oct 2011 17:59:40 -0000
@@ -1250,9 +1250,11 @@
 		rlim = &p->p_rlimit[RLIMIT_CPU];
 		sig = 0;
 		if (__predict_false(runtm >= rlim->rlim_cur)) {
-			if (runtm >= rlim->rlim_max)
+			if (runtm >= rlim->rlim_max) {
 				sig = SIGKILL;
-			else {
+				log(LOG_ERR, "pid %d is killed: %s\n", p->p_pid, "exceeded RLIMIT_CPU");
+				uprintf("sorry, pid %d, command %s, is killed: %s\n", p->p_pid, p->p_comm, "exceeded RLIMIT_CPU");
+			} else {
 				sig = SIGXCPU;
 				if (rlim->rlim_cur < rlim->rlim_max)
 					rlim->rlim_cur += 5;
@@ -1262,7 +1264,7 @@
 		if (__predict_false(runtm < 0)) {
 			if (!backwards) {
 				backwards = true;
-				printf("WARNING: negative runtime; "
+				log(LOG_WARNING, "WARNING: negative runtime; "
 				    "monotonic clock has gone backwards\n");
 			}
 		} else if (__predict_false(sig)) {

>Release-Note:

>Audit-Trail:
From: "Alan Barrett" <apb@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc: 
Subject: PR/45421 CVS commit: src/sys/kern
Date: Wed, 5 Oct 2011 13:05:49 +0000

 Module Name:	src
 Committed By:	apb
 Date:		Wed Oct  5 13:05:49 UTC 2011

 Modified Files:
 	src/sys/kern: kern_synch.c

 Log Message:
 Print "WARNING: negative runtime; monotonic clock has gone backwards\n"
 using log(LOG_WARNING, ...), not just printf(...).

 From PR 45421 by Greg Woods.


 To generate a diff of this commit:
 cvs rdiff -u -r1.291 -r1.292 src/sys/kern/kern_synch.c

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.

From: "Alan Barrett" <apb@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc: 
Subject: PR/45421 CVS commit: src/sys/kern
Date: Wed, 5 Oct 2011 13:22:13 +0000

 Module Name:	src
 Committed By:	apb
 Date:		Wed Oct  5 13:22:13 UTC 2011

 Modified Files:
 	src/sys/kern: kern_synch.c

 Log Message:
 When killing a process due to RLIMIT_CPU, also log a message
 with LOG_NOTICE, and print a message to the user with uprintf.

 From PR 45421 by Greg Woods, but I changed the log priority (the user
 might think it's an error, but the kernel is just doing its job) and the
 wording of the message, and I edited a nearby comment.


 To generate a diff of this commit:
 cvs rdiff -u -r1.292 -r1.293 src/sys/kern/kern_synch.c

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.

State-Changed-From-To: open->closed
State-Changed-By: apb@NetBSD.org
State-Changed-When: Wed, 05 Oct 2011 13:54:52 +0000
State-Changed-Why:
patch applied, with small changes.


>Unformatted:

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