# svn status
M       kern/kern_resource.c
M       sys/resourcevar.h
M       vm/vm_mmap.c

Index: kern/kern_resource.c
===================================================================
--- kern/kern_resource.c	(revision 264283)
+++ kern/kern_resource.c	(working copy)
@@ -39,6 +39,8 @@ __FBSDID("$FreeBSD$");
 
 #include "opt_compat.h"
 
+#define _RLIMIT_IDENT
+
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/sysproto.h>
@@ -58,6 +60,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/syscallsubr.h>
 #include <sys/sysctl.h>
 #include <sys/sysent.h>
+#include <sys/syslog.h>
 #include <sys/time.h>
 #include <sys/umtx.h>
 
@@ -1228,6 +1231,67 @@ lim_rlimit(struct proc *p, int which, st
 		p->p_sysent->sv_fixlimit(rlp, which);
 }
 
+static int kern_loglimexceeded = 1;
+SYSCTL_INT(_kern, OID_AUTO, loglimexceeded, CTLFLAG_RW, &kern_loglimexceeded,
+    0, "Log processes exceeding setrlimit(2) limits to syslog(3)");
+
+int
+lim_exceeded(struct proc *p, int which, rlim_t newsize)
+{
+	rlim_t curlim;
+	const char *desc;
+	int limexceeded;
+
+	PROC_LOCK_ASSERT(p, MA_OWNED);
+
+	curlim = lim_cur(p, which);
+	limexceeded = newsize > curlim;
+
+	if (kern_loglimexceeded == 0)
+		goto out;
+
+	switch (which) {
+	case RLIMIT_CPU:
+		desc = "seconds";
+		break;
+	case RLIMIT_FSIZE:
+	case RLIMIT_DATA:
+	case RLIMIT_STACK:
+	case RLIMIT_CORE:
+	case RLIMIT_RSS:
+	case RLIMIT_MEMLOCK:
+	case RLIMIT_VMEM:
+	case RLIMIT_SBSIZE:
+	case RLIMIT_SWAP:
+		desc = "bytes";
+		break;
+	case RLIMIT_NPROC:
+		desc = "processes";
+		break;
+	case RLIMIT_NOFILE:
+		desc = "files";
+		break;
+	case RLIMIT_NPTS:
+		desc = "pseudo-terminals";
+		break;
+	case RLIMIT_KQUEUES:
+		desc = "kqueues";
+		break;
+	default:
+		desc = "resources";
+		break;
+	}
+
+	if (limexceeded)
+		logproc(LOG_INFO, p, __FUNCTION__, "attempted to allocate %ld "
+		    "%s over %s limit of %ld\n",
+		    (long)(newsize - curlim), desc, rlimit_ident[which],
+		    (long)curlim);
+
+out:
+	return (limexceeded);
+}
+
 void
 uihashinit()
 {
Index: sys/resourcevar.h
===================================================================
--- sys/resourcevar.h	(revision 264283)
+++ sys/resourcevar.h	(working copy)
@@ -128,6 +128,7 @@ struct plimit
 	*lim_alloc(void);
 void	 lim_copy(struct plimit *dst, struct plimit *src);
 rlim_t	 lim_cur(struct proc *p, int which);
+int	 lim_exceeded(struct proc *p, int which, rlim_t newsize);
 void	 lim_fork(struct proc *p1, struct proc *p2);
 void	 lim_free(struct plimit *limp);
 struct plimit
Index: vm/vm_mmap.c
===================================================================
--- vm/vm_mmap.c	(revision 264283)
+++ vm/vm_mmap.c	(working copy)
@@ -1520,7 +1520,7 @@ vm_mmap(vm_map_t map, vm_offset_t *addr,
 
 	if (map == &td->td_proc->p_vmspace->vm_map) {
 		PROC_LOCK(td->td_proc);
-		if (map->size + size > lim_cur(td->td_proc, RLIMIT_VMEM)) {
+		if (lim_exceeded(td->td_proc, RLIMIT_VMEM, map->size + size)) {
 			PROC_UNLOCK(td->td_proc);
 			return (ENOMEM);
 		}