svn commit: r226092 - in stable/9/sys: kern sys

Edward Tomasz Napierala trasz at FreeBSD.org
Fri Oct 7 06:46:47 UTC 2011


Author: trasz
Date: Fri Oct  7 06:46:46 2011
New Revision: 226092
URL: http://svn.freebsd.org/changeset/base/226092

Log:
  MFC r225938:
  
  Fix bug introduced in r225641, which would cause panic if racct_proc_fork()
  returned error -- the racct_destroy_locked() would get called twice.
  
  MFC r225940:
  
  Fix another bug introduced in r225641, which caused rctl to access certain
  fields in 'struct proc' before they got initialized in do_fork().
  
  MFC r225944:
  
  Move some code inside the racct_proc_fork(); it spares a few lock operations
  and it's more logical this way.
  
  MFC r225981:
  
  Actually enforce limit for inheritable resources on fork.
  
  Approved by:	re (kib)

Modified:
  stable/9/sys/kern/kern_fork.c
  stable/9/sys/kern/kern_racct.c
  stable/9/sys/kern/kern_rctl.c
  stable/9/sys/sys/racct.h
Directory Properties:
  stable/9/sys/   (props changed)
  stable/9/sys/amd64/include/xen/   (props changed)
  stable/9/sys/boot/   (props changed)
  stable/9/sys/boot/i386/efi/   (props changed)
  stable/9/sys/boot/ia64/efi/   (props changed)
  stable/9/sys/boot/ia64/ski/   (props changed)
  stable/9/sys/boot/powerpc/boot1.chrp/   (props changed)
  stable/9/sys/boot/powerpc/ofw/   (props changed)
  stable/9/sys/cddl/contrib/opensolaris/   (props changed)
  stable/9/sys/conf/   (props changed)
  stable/9/sys/contrib/dev/acpica/   (props changed)
  stable/9/sys/contrib/octeon-sdk/   (props changed)
  stable/9/sys/contrib/pf/   (props changed)
  stable/9/sys/contrib/x86emu/   (props changed)

Modified: stable/9/sys/kern/kern_fork.c
==============================================================================
--- stable/9/sys/kern/kern_fork.c	Fri Oct  7 06:13:38 2011	(r226091)
+++ stable/9/sys/kern/kern_fork.c	Fri Oct  7 06:46:46 2011	(r226092)
@@ -879,17 +879,6 @@ fork1(struct thread *td, int flags, int 
 		goto fail1;
 	}
 
-#ifdef RACCT
-	PROC_LOCK(newproc);
-	error = racct_add(newproc, RACCT_NPROC, 1);
-	error += racct_add(newproc, RACCT_NTHR, 1);
-	PROC_UNLOCK(newproc);
-	if (error != 0) {
-		error = EAGAIN;
-		goto fail1;
-	}
-#endif
-
 #ifdef MAC
 	mac_proc_init(newproc);
 #endif
@@ -939,6 +928,7 @@ fork1(struct thread *td, int flags, int 
 		if (flags & RFPROCDESC)
 			procdesc_finit(newproc->p_procdesc, fp_procdesc);
 #endif
+		racct_proc_fork_done(newproc);
 		return (0);
 	}
 

Modified: stable/9/sys/kern/kern_racct.c
==============================================================================
--- stable/9/sys/kern/kern_racct.c	Fri Oct  7 06:13:38 2011	(r226091)
+++ stable/9/sys/kern/kern_racct.c	Fri Oct  7 06:46:46 2011	(r226092)
@@ -261,12 +261,8 @@ racct_alloc_resource(struct racct *racct
 	}
 }
 
-/*
- * Increase allocation of 'resource' by 'amount' for process 'p'.
- * Return 0 if it's below limits, or errno, if it's not.
- */
-int
-racct_add(struct proc *p, int resource, uint64_t amount)
+static int
+racct_add_locked(struct proc *p, int resource, uint64_t amount)
 {
 #ifdef RCTL
 	int error;
@@ -282,23 +278,35 @@ racct_add(struct proc *p, int resource, 
 	 */
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 
-	mtx_lock(&racct_lock);
 #ifdef RCTL
 	error = rctl_enforce(p, resource, amount);
 	if (error && RACCT_IS_DENIABLE(resource)) {
 		SDT_PROBE(racct, kernel, rusage, add_failure, p, resource,
 		    amount, 0, 0);
-		mtx_unlock(&racct_lock);
 		return (error);
 	}
 #endif
 	racct_alloc_resource(p->p_racct, resource, amount);
 	racct_add_cred_locked(p->p_ucred, resource, amount);
-	mtx_unlock(&racct_lock);
 
 	return (0);
 }
 
+/*
+ * Increase allocation of 'resource' by 'amount' for process 'p'.
+ * Return 0 if it's below limits, or errno, if it's not.
+ */
+int
+racct_add(struct proc *p, int resource, uint64_t amount)
+{
+	int error;
+
+	mtx_lock(&racct_lock);
+	error = racct_add_locked(p, resource, amount);
+	mtx_unlock(&racct_lock);
+	return (error);
+}
+
 static void
 racct_add_cred_locked(struct ucred *cred, int resource, uint64_t amount)
 {
@@ -559,6 +567,12 @@ racct_proc_fork(struct proc *parent, str
 	PROC_LOCK(child);
 	mtx_lock(&racct_lock);
 
+#ifdef RCTL
+	error = rctl_proc_fork(parent, child);
+	if (error != 0)
+		goto out;
+#endif
+
 	/*
 	 * Inherit resource usage.
 	 */
@@ -569,32 +583,14 @@ racct_proc_fork(struct proc *parent, str
 
 		error = racct_set_locked(child, i,
 		    parent->p_racct->r_resources[i]);
-		if (error != 0) {
-			/*
-			 * XXX: The only purpose of these two lines is
-			 * to prevent from tripping checks in racct_destroy().
-			 */
-			for (i = 0; i <= RACCT_MAX; i++)
-				racct_set_locked(child, i, 0);
+		if (error != 0)
 			goto out;
-		}
 	}
 
-#ifdef RCTL
-	error = rctl_proc_fork(parent, child);
-	if (error != 0) {
-		/*
-		 * XXX: The only purpose of these two lines is to prevent from
-		 * tripping checks in racct_destroy().
-		 */
-		for (i = 0; i <= RACCT_MAX; i++)
-			racct_set_locked(child, i, 0);
-	}
-#endif
+	error = racct_add_locked(child, RACCT_NPROC, 1);
+	error += racct_add_locked(child, RACCT_NTHR, 1);
 
 out:
-	if (error != 0)
-		racct_destroy_locked(&child->p_racct);
 	mtx_unlock(&racct_lock);
 	PROC_UNLOCK(child);
 	PROC_UNLOCK(parent);
@@ -602,6 +598,24 @@ out:
 	return (error);
 }
 
+/*
+ * Called at the end of fork1(), to handle rules that require the process
+ * to be fully initialized.
+ */
+void
+racct_proc_fork_done(struct proc *child)
+{
+
+#ifdef RCTL
+	PROC_LOCK(child);
+	mtx_lock(&racct_lock);
+	rctl_enforce(child, RACCT_NPROC, 0);
+	rctl_enforce(child, RACCT_NTHR, 0);
+	mtx_unlock(&racct_lock);
+	PROC_UNLOCK(child);
+#endif
+}
+
 void
 racct_proc_exit(struct proc *p)
 {
@@ -827,6 +841,11 @@ racct_proc_fork(struct proc *parent, str
 }
 
 void
+racct_proc_fork_done(struct proc *child)
+{
+}
+
+void
 racct_proc_exit(struct proc *p)
 {
 }

Modified: stable/9/sys/kern/kern_rctl.c
==============================================================================
--- stable/9/sys/kern/kern_rctl.c	Fri Oct  7 06:13:38 2011	(r226091)
+++ stable/9/sys/kern/kern_rctl.c	Fri Oct  7 06:46:46 2011	(r226092)
@@ -312,6 +312,16 @@ rctl_enforce(struct proc *p, int resourc
 			if (link->rrl_exceeded != 0)
 				continue;
 
+			/*
+			 * If the process state is not fully initialized yet,
+			 * we can't access most of the required fields, e.g.
+			 * p->p_comm.  This happens when called from fork1().
+			 * Ignore this rule for now; it will be processed just
+			 * after fork, when called from racct_proc_fork_done().
+			 */
+			if (p->p_state != PRS_NORMAL)
+				continue;
+
 			if (!ppsratecheck(&lasttime, &curtime, 10))
 				continue;
 
@@ -335,6 +345,9 @@ rctl_enforce(struct proc *p, int resourc
 			if (link->rrl_exceeded != 0)
 				continue;
 
+			if (p->p_state != PRS_NORMAL)
+				continue;
+	
 			buf = malloc(RCTL_LOG_BUFSIZE, M_RCTL, M_NOWAIT);
 			if (buf == NULL) {
 				printf("rctl_enforce: out of memory\n");
@@ -357,23 +370,15 @@ rctl_enforce(struct proc *p, int resourc
 			if (link->rrl_exceeded != 0)
 				continue;
 
+			if (p->p_state != PRS_NORMAL)
+				continue;
+
 			KASSERT(rule->rr_action > 0 &&
 			    rule->rr_action <= RCTL_ACTION_SIGNAL_MAX,
 			    ("rctl_enforce: unknown action %d",
 			     rule->rr_action));
 
 			/*
-			 * We're supposed to send a signal, but the process
-			 * is not fully initialized yet, probably because we
-			 * got called from fork1().  For now just deny the
-			 * allocation instead.
-			 */
-			if (p->p_state != PRS_NORMAL) {
-				should_deny = 1;
-				continue;
-			}
-
-			/*
 			 * We're using the fact that RCTL_ACTION_SIG* values
 			 * are equal to their counterparts from sys/signal.h.
 			 */

Modified: stable/9/sys/sys/racct.h
==============================================================================
--- stable/9/sys/sys/racct.h	Fri Oct  7 06:13:38 2011	(r226091)
+++ stable/9/sys/sys/racct.h	Fri Oct  7 06:46:46 2011	(r226092)
@@ -137,6 +137,7 @@ void	racct_create(struct racct **racctp)
 void	racct_destroy(struct racct **racctp);
 
 int	racct_proc_fork(struct proc *parent, struct proc *child);
+void	racct_proc_fork_done(struct proc *child);
 void	racct_proc_exit(struct proc *p);
 
 void	racct_proc_ucred_changed(struct proc *p, struct ucred *oldcred,


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