Merge branch 'master' into for-next

Fast-forward merge with Linus to be able to merge patches
based on more recent version of the tree.

3 files changed, 212 insertions, 66 deletions

diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c
index 56410faa4550..00fba2bab87d 100644
--- a/ipc/ipc_sysctl.c
+++ b/ipc/ipc_sysctl.c
@@ -31,12 +31,37 @@ static int proc_ipc_dointvec(ctl_table *table, int write,
 	void __user *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table ipc_table;
+
 	memcpy(&ipc_table, table, sizeof(ipc_table));
 	ipc_table.data = get_ipc(table);
 
 	return proc_dointvec(&ipc_table, write, buffer, lenp, ppos);
 }
 
+static int proc_ipc_dointvec_minmax(ctl_table *table, int write,
+	void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table ipc_table;
+
+	memcpy(&ipc_table, table, sizeof(ipc_table));
+	ipc_table.data = get_ipc(table);
+
+	return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
+}
+
+static int proc_ipc_dointvec_minmax_orphans(ctl_table *table, int write,
+	void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct ipc_namespace *ns = current->nsproxy->ipc_ns;
+	int err = proc_ipc_dointvec_minmax(table, write, buffer, lenp, ppos);
+
+	if (err < 0)
+		return err;
+	if (ns->shm_rmid_forced)
+		shm_destroy_orphaned(ns);
+	return err;
+}
+
 static int proc_ipc_callback_dointvec(ctl_table *table, int write,
 	void __user *buffer, size_t *lenp, loff_t *ppos)
 {
@@ -125,6 +150,8 @@ static int proc_ipcauto_dointvec_minmax(ctl_table *table, int write,
 #else
 #define proc_ipc_doulongvec_minmax NULL
 #define proc_ipc_dointvec	   NULL
+#define proc_ipc_dointvec_minmax   NULL
+#define proc_ipc_dointvec_minmax_orphans   NULL
 #define proc_ipc_callback_dointvec NULL
 #define proc_ipcauto_dointvec_minmax NULL
 #endif
@@ -155,6 +182,15 @@ static struct ctl_table ipc_kern_table[] = {
 		.proc_handler	= proc_ipc_dointvec,
 	},
 	{
+		.procname	= "shm_rmid_forced",
+		.data		= &init_ipc_ns.shm_rmid_forced,
+		.maxlen		= sizeof(init_ipc_ns.shm_rmid_forced),
+		.mode		= 0644,
+		.proc_handler	= proc_ipc_dointvec_minmax_orphans,
+		.extra1		= &zero,
+		.extra2		= &one,
+	},
+	{
 		.procname	= "msgmax",
 		.data		= &init_ipc_ns.msg_ctlmax,
 		.maxlen		= sizeof (init_ipc_ns.msg_ctlmax),
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 14fb6d67e6a3..ed049ea568f4 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -113,72 +113,75 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
 {
 	struct user_struct *u = current_user();
 	struct inode *inode;
+	int ret = -ENOMEM;
 
 	inode = new_inode(sb);
-	if (inode) {
-		inode->i_ino = get_next_ino();
-		inode->i_mode = mode;
-		inode->i_uid = current_fsuid();
-		inode->i_gid = current_fsgid();
-		inode->i_mtime = inode->i_ctime = inode->i_atime =
-				CURRENT_TIME;
+	if (!inode)
+		goto err;
 
-		if (S_ISREG(mode)) {
-			struct mqueue_inode_info *info;
-			struct task_struct *p = current;
-			unsigned long mq_bytes, mq_msg_tblsz;
-
-			inode->i_fop = &mqueue_file_operations;
-			inode->i_size = FILENT_SIZE;
-			/* mqueue specific info */
-			info = MQUEUE_I(inode);
-			spin_lock_init(&info->lock);
-			init_waitqueue_head(&info->wait_q);
-			INIT_LIST_HEAD(&info->e_wait_q[0].list);
-			INIT_LIST_HEAD(&info->e_wait_q[1].list);
-			info->notify_owner = NULL;
-			info->qsize = 0;
-			info->user = NULL;	/* set when all is ok */
-			memset(&info->attr, 0, sizeof(info->attr));
-			info->attr.mq_maxmsg = ipc_ns->mq_msg_max;
-			info->attr.mq_msgsize = ipc_ns->mq_msgsize_max;
-			if (attr) {
-				info->attr.mq_maxmsg = attr->mq_maxmsg;
-				info->attr.mq_msgsize = attr->mq_msgsize;
-			}
-			mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
-			info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
-			if (!info->messages)
-				goto out_inode;
-
-			mq_bytes = (mq_msg_tblsz +
-				(info->attr.mq_maxmsg * info->attr.mq_msgsize));
-
-			spin_lock(&mq_lock);
-			if (u->mq_bytes + mq_bytes < u->mq_bytes ||
-		 	    u->mq_bytes + mq_bytes >
-			    task_rlimit(p, RLIMIT_MSGQUEUE)) {
-				spin_unlock(&mq_lock);
-				/* mqueue_evict_inode() releases info->messages */
-				goto out_inode;
-			}
-			u->mq_bytes += mq_bytes;
-			spin_unlock(&mq_lock);
+	inode->i_ino = get_next_ino();
+	inode->i_mode = mode;
+	inode->i_uid = current_fsuid();
+	inode->i_gid = current_fsgid();
+	inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME;
+
+	if (S_ISREG(mode)) {
+		struct mqueue_inode_info *info;
+		struct task_struct *p = current;
+		unsigned long mq_bytes, mq_msg_tblsz;
+
+		inode->i_fop = &mqueue_file_operations;
+		inode->i_size = FILENT_SIZE;
+		/* mqueue specific info */
+		info = MQUEUE_I(inode);
+		spin_lock_init(&info->lock);
+		init_waitqueue_head(&info->wait_q);
+		INIT_LIST_HEAD(&info->e_wait_q[0].list);
+		INIT_LIST_HEAD(&info->e_wait_q[1].list);
+		info->notify_owner = NULL;
+		info->qsize = 0;
+		info->user = NULL;	/* set when all is ok */
+		memset(&info->attr, 0, sizeof(info->attr));
+		info->attr.mq_maxmsg = ipc_ns->mq_msg_max;
+		info->attr.mq_msgsize = ipc_ns->mq_msgsize_max;
+		if (attr) {
+			info->attr.mq_maxmsg = attr->mq_maxmsg;
+			info->attr.mq_msgsize = attr->mq_msgsize;
+		}
+		mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
+		info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
+		if (!info->messages)
+			goto out_inode;
 
-			/* all is ok */
-			info->user = get_uid(u);
-		} else if (S_ISDIR(mode)) {
-			inc_nlink(inode);
-			/* Some things misbehave if size == 0 on a directory */
-			inode->i_size = 2 * DIRENT_SIZE;
-			inode->i_op = &mqueue_dir_inode_operations;
-			inode->i_fop = &simple_dir_operations;
+		mq_bytes = (mq_msg_tblsz +
+			(info->attr.mq_maxmsg * info->attr.mq_msgsize));
+
+		spin_lock(&mq_lock);
+		if (u->mq_bytes + mq_bytes < u->mq_bytes ||
+		    u->mq_bytes + mq_bytes > task_rlimit(p, RLIMIT_MSGQUEUE)) {
+			spin_unlock(&mq_lock);
+			/* mqueue_evict_inode() releases info->messages */
+			ret = -EMFILE;
+			goto out_inode;
 		}
+		u->mq_bytes += mq_bytes;
+		spin_unlock(&mq_lock);
+
+		/* all is ok */
+		info->user = get_uid(u);
+	} else if (S_ISDIR(mode)) {
+		inc_nlink(inode);
+		/* Some things misbehave if size == 0 on a directory */
+		inode->i_size = 2 * DIRENT_SIZE;
+		inode->i_op = &mqueue_dir_inode_operations;
+		inode->i_fop = &simple_dir_operations;
 	}
+
 	return inode;
 out_inode:
 	iput(inode);
-	return NULL;
+err:
+	return ERR_PTR(ret);
 }
 
 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
@@ -194,8 +197,8 @@ static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
 
 	inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO,
 				NULL);
-	if (!inode) {
-		error = -ENOMEM;
+	if (IS_ERR(inode)) {
+		error = PTR_ERR(inode);
 		goto out;
 	}
 
@@ -315,8 +318,8 @@ static int mqueue_create(struct inode *dir, struct dentry *dentry,
 	spin_unlock(&mq_lock);
 
 	inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
-	if (!inode) {
-		error = -ENOMEM;
+	if (IS_ERR(inode)) {
+		error = PTR_ERR(inode);
 		spin_lock(&mq_lock);
 		ipc_ns->mq_queues_count--;
 		goto out_unlock;
diff --git a/ipc/shm.c b/ipc/shm.c
index 27884adb1a90..02ecf2c078fc 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -74,6 +74,7 @@ void shm_init_ns(struct ipc_namespace *ns)
 	ns->shm_ctlmax = SHMMAX;
 	ns->shm_ctlall = SHMALL;
 	ns->shm_ctlmni = SHMMNI;
+	ns->shm_rmid_forced = 0;
 	ns->shm_tot = 0;
 	ipc_init_ids(&shm_ids(ns));
 }
@@ -104,9 +105,16 @@ void shm_exit_ns(struct ipc_namespace *ns)
 }
 #endif
 
-void __init shm_init (void)
+static int __init ipc_ns_init(void)
 {
 	shm_init_ns(&init_ipc_ns);
+	return 0;
+}
+
+pure_initcall(ipc_ns_init);
+
+void __init shm_init (void)
+{
 	ipc_init_proc_interface("sysvipc/shm",
 #if BITS_PER_LONG <= 32
 				"       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime        rss       swap\n",
@@ -130,6 +138,12 @@ static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 	return container_of(ipcp, struct shmid_kernel, shm_perm);
 }
 
+static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
+{
+	rcu_read_lock();
+	spin_lock(&ipcp->shm_perm.lock);
+}
+
 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
 						int id)
 {
@@ -187,6 +201,23 @@ static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 }
 
 /*
+ * shm_may_destroy - identifies whether shm segment should be destroyed now
+ *
+ * Returns true if and only if there are no active users of the segment and
+ * one of the following is true:
+ *
+ * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
+ *
+ * 2) sysctl kernel.shm_rmid_forced is set to 1.
+ */
+static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
+{
+	return (shp->shm_nattch == 0) &&
+	       (ns->shm_rmid_forced ||
+		(shp->shm_perm.mode & SHM_DEST));
+}
+
+/*
  * remove the attach descriptor vma.
  * free memory for segment if it is marked destroyed.
  * The descriptor has already been removed from the current->mm->mmap list
@@ -206,14 +237,90 @@ static void shm_close(struct vm_area_struct *vma)
 	shp->shm_lprid = task_tgid_vnr(current);
 	shp->shm_dtim = get_seconds();
 	shp->shm_nattch--;
-	if(shp->shm_nattch == 0 &&
-	   shp->shm_perm.mode & SHM_DEST)
+	if (shm_may_destroy(ns, shp))
 		shm_destroy(ns, shp);
 	else
 		shm_unlock(shp);
 	up_write(&shm_ids(ns).rw_mutex);
 }
 
+/* Called with ns->shm_ids(ns).rw_mutex locked */
+static int shm_try_destroy_current(int id, void *p, void *data)
+{
+	struct ipc_namespace *ns = data;
+	struct kern_ipc_perm *ipcp = p;
+	struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
+
+	if (shp->shm_creator != current)
+		return 0;
+
+	/*
+	 * Mark it as orphaned to destroy the segment when
+	 * kernel.shm_rmid_forced is changed.
+	 * It is noop if the following shm_may_destroy() returns true.
+	 */
+	shp->shm_creator = NULL;
+
+	/*
+	 * Don't even try to destroy it.  If shm_rmid_forced=0 and IPC_RMID
+	 * is not set, it shouldn't be deleted here.
+	 */
+	if (!ns->shm_rmid_forced)
+		return 0;
+
+	if (shm_may_destroy(ns, shp)) {
+		shm_lock_by_ptr(shp);
+		shm_destroy(ns, shp);
+	}
+	return 0;
+}
+
+/* Called with ns->shm_ids(ns).rw_mutex locked */
+static int shm_try_destroy_orphaned(int id, void *p, void *data)
+{
+	struct ipc_namespace *ns = data;
+	struct kern_ipc_perm *ipcp = p;
+	struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
+
+	/*
+	 * We want to destroy segments without users and with already
+	 * exit'ed originating process.
+	 *
+	 * As shp->* are changed under rw_mutex, it's safe to skip shp locking.
+	 */
+	if (shp->shm_creator != NULL)
+		return 0;
+
+	if (shm_may_destroy(ns, shp)) {
+		shm_lock_by_ptr(shp);
+		shm_destroy(ns, shp);
+	}
+	return 0;
+}
+
+void shm_destroy_orphaned(struct ipc_namespace *ns)
+{
+	down_write(&shm_ids(ns).rw_mutex);
+	if (shm_ids(ns).in_use)
+		idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
+	up_write(&shm_ids(ns).rw_mutex);
+}
+
+
+void exit_shm(struct task_struct *task)
+{
+	struct ipc_namespace *ns = task->nsproxy->ipc_ns;
+
+	if (shm_ids(ns).in_use == 0)
+		return;
+
+	/* Destroy all already created segments, but not mapped yet */
+	down_write(&shm_ids(ns).rw_mutex);
+	if (shm_ids(ns).in_use)
+		idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
+	up_write(&shm_ids(ns).rw_mutex);
+}
+
 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	struct file *file = vma->vm_file;
@@ -404,6 +511,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 	shp->shm_segsz = size;
 	shp->shm_nattch = 0;
 	shp->shm_file = file;
+	shp->shm_creator = current;
 	/*
 	 * shmid gets reported as "inode#" in /proc/pid/maps.
 	 * proc-ps tools use this. Changing this will break them.
@@ -950,8 +1058,7 @@ out_nattch:
 	shp = shm_lock(ns, shmid);
 	BUG_ON(IS_ERR(shp));
 	shp->shm_nattch--;
-	if(shp->shm_nattch == 0 &&
-	   shp->shm_perm.mode & SHM_DEST)
+	if (shm_may_destroy(ns, shp))
 		shm_destroy(ns, shp);
 	else
 		shm_unlock(shp);