Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 428 insertions, 0 deletions

diff --git a/net/rds/cong.c b/net/rds/cong.c
new file mode 100644
index 000000000..f7634ce3f
--- /dev/null
+++ b/net/rds/cong.c
@@ -0,0 +1,428 @@
+/*
+ * Copyright (c) 2007, 2017 Oracle and/or its affiliates. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/rbtree.h>
+#include <linux/bitops.h>
+#include <linux/export.h>
+
+#include "rds.h"
+
+/*
+ * This file implements the receive side of the unconventional congestion
+ * management in RDS.
+ *
+ * Messages waiting in the receive queue on the receiving socket are accounted
+ * against the sockets SO_RCVBUF option value.  Only the payload bytes in the
+ * message are accounted for.  If the number of bytes queued equals or exceeds
+ * rcvbuf then the socket is congested.  All sends attempted to this socket's
+ * address should return block or return -EWOULDBLOCK.
+ *
+ * Applications are expected to be reasonably tuned such that this situation
+ * very rarely occurs.  An application encountering this "back-pressure" is
+ * considered a bug.
+ *
+ * This is implemented by having each node maintain bitmaps which indicate
+ * which ports on bound addresses are congested.  As the bitmap changes it is
+ * sent through all the connections which terminate in the local address of the
+ * bitmap which changed.
+ *
+ * The bitmaps are allocated as connections are brought up.  This avoids
+ * allocation in the interrupt handling path which queues messages on sockets.
+ * The dense bitmaps let transports send the entire bitmap on any bitmap change
+ * reasonably efficiently.  This is much easier to implement than some
+ * finer-grained communication of per-port congestion.  The sender does a very
+ * inexpensive bit test to test if the port it's about to send to is congested
+ * or not.
+ */
+
+/*
+ * Interaction with poll is a tad tricky. We want all processes stuck in
+ * poll to wake up and check whether a congested destination became uncongested.
+ * The really sad thing is we have no idea which destinations the application
+ * wants to send to - we don't even know which rds_connections are involved.
+ * So until we implement a more flexible rds poll interface, we have to make
+ * do with this:
+ * We maintain a global counter that is incremented each time a congestion map
+ * update is received. Each rds socket tracks this value, and if rds_poll
+ * finds that the saved generation number is smaller than the global generation
+ * number, it wakes up the process.
+ */
+static atomic_t		rds_cong_generation = ATOMIC_INIT(0);
+
+/*
+ * Congestion monitoring
+ */
+static LIST_HEAD(rds_cong_monitor);
+static DEFINE_RWLOCK(rds_cong_monitor_lock);
+
+/*
+ * Yes, a global lock.  It's used so infrequently that it's worth keeping it
+ * global to simplify the locking.  It's only used in the following
+ * circumstances:
+ *
+ *  - on connection buildup to associate a conn with its maps
+ *  - on map changes to inform conns of a new map to send
+ *
+ *  It's sadly ordered under the socket callback lock and the connection lock.
+ *  Receive paths can mark ports congested from interrupt context so the
+ *  lock masks interrupts.
+ */
+static DEFINE_SPINLOCK(rds_cong_lock);
+static struct rb_root rds_cong_tree = RB_ROOT;
+
+static struct rds_cong_map *rds_cong_tree_walk(const struct in6_addr *addr,
+					       struct rds_cong_map *insert)
+{
+	struct rb_node **p = &rds_cong_tree.rb_node;
+	struct rb_node *parent = NULL;
+	struct rds_cong_map *map;
+
+	while (*p) {
+		int diff;
+
+		parent = *p;
+		map = rb_entry(parent, struct rds_cong_map, m_rb_node);
+
+		diff = rds_addr_cmp(addr, &map->m_addr);
+		if (diff < 0)
+			p = &(*p)->rb_left;
+		else if (diff > 0)
+			p = &(*p)->rb_right;
+		else
+			return map;
+	}
+
+	if (insert) {
+		rb_link_node(&insert->m_rb_node, parent, p);
+		rb_insert_color(&insert->m_rb_node, &rds_cong_tree);
+	}
+	return NULL;
+}
+
+/*
+ * There is only ever one bitmap for any address.  Connections try and allocate
+ * these bitmaps in the process getting pointers to them.  The bitmaps are only
+ * ever freed as the module is removed after all connections have been freed.
+ */
+static struct rds_cong_map *rds_cong_from_addr(const struct in6_addr *addr)
+{
+	struct rds_cong_map *map;
+	struct rds_cong_map *ret = NULL;
+	unsigned long zp;
+	unsigned long i;
+	unsigned long flags;
+
+	map = kzalloc_obj(struct rds_cong_map);
+	if (!map)
+		return NULL;
+
+	map->m_addr = *addr;
+	init_waitqueue_head(&map->m_waitq);
+	INIT_LIST_HEAD(&map->m_conn_list);
+
+	for (i = 0; i < RDS_CONG_MAP_PAGES; i++) {
+		zp = get_zeroed_page(GFP_KERNEL);
+		if (zp == 0)
+			goto out;
+		map->m_page_addrs[i] = zp;
+	}
+
+	spin_lock_irqsave(&rds_cong_lock, flags);
+	ret = rds_cong_tree_walk(addr, map);
+	spin_unlock_irqrestore(&rds_cong_lock, flags);
+
+	if (!ret) {
+		ret = map;
+		map = NULL;
+	}
+
+out:
+	if (map) {
+		for (i = 0; i < RDS_CONG_MAP_PAGES && map->m_page_addrs[i]; i++)
+			free_page(map->m_page_addrs[i]);
+		kfree(map);
+	}
+
+	rdsdebug("map %p for addr %pI6c\n", ret, addr);
+
+	return ret;
+}
+
+/*
+ * Put the conn on its local map's list.  This is called when the conn is
+ * really added to the hash.  It's nested under the rds_conn_lock, sadly.
+ */
+void rds_cong_add_conn(struct rds_connection *conn)
+{
+	unsigned long flags;
+
+	rdsdebug("conn %p now on map %p\n", conn, conn->c_lcong);
+	spin_lock_irqsave(&rds_cong_lock, flags);
+	list_add_tail(&conn->c_map_item, &conn->c_lcong->m_conn_list);
+	spin_unlock_irqrestore(&rds_cong_lock, flags);
+}
+
+void rds_cong_remove_conn(struct rds_connection *conn)
+{
+	unsigned long flags;
+
+	rdsdebug("removing conn %p from map %p\n", conn, conn->c_lcong);
+	spin_lock_irqsave(&rds_cong_lock, flags);
+	list_del_init(&conn->c_map_item);
+	spin_unlock_irqrestore(&rds_cong_lock, flags);
+}
+
+int rds_cong_get_maps(struct rds_connection *conn)
+{
+	conn->c_lcong = rds_cong_from_addr(&conn->c_laddr);
+	conn->c_fcong = rds_cong_from_addr(&conn->c_faddr);
+
+	if (!(conn->c_lcong && conn->c_fcong))
+		return -ENOMEM;
+
+	return 0;
+}
+
+void rds_cong_queue_updates(struct rds_cong_map *map)
+{
+	struct rds_connection *conn;
+	unsigned long flags;
+
+	spin_lock_irqsave(&rds_cong_lock, flags);
+
+	list_for_each_entry(conn, &map->m_conn_list, c_map_item) {
+		struct rds_conn_path *cp = &conn->c_path[0];
+
+		rcu_read_lock();
+		if (!test_and_set_bit(0, &conn->c_map_queued) &&
+		    !rds_destroy_pending(cp->cp_conn)) {
+			rds_stats_inc(s_cong_update_queued);
+			/* We cannot inline the call to rds_send_xmit() here
+			 * for two reasons (both pertaining to a TCP transport):
+			 * 1. When we get here from the receive path, we
+			 *    are already holding the sock_lock (held by
+			 *    tcp_v4_rcv()). So inlining calls to
+			 *    tcp_setsockopt and/or tcp_sendmsg will deadlock
+			 *    when it tries to get the sock_lock())
+			 * 2. Interrupts are masked so that we can mark the
+			 *    port congested from both send and recv paths.
+			 *    (See comment around declaration of rdc_cong_lock).
+			 *    An attempt to get the sock_lock() here will
+			 *    therefore trigger warnings.
+			 * Defer the xmit to rds_send_worker() instead.
+			 */
+			queue_delayed_work(cp->cp_wq, &cp->cp_send_w, 0);
+		}
+		rcu_read_unlock();
+	}
+
+	spin_unlock_irqrestore(&rds_cong_lock, flags);
+}
+
+void rds_cong_map_updated(struct rds_cong_map *map, uint64_t portmask)
+{
+	rdsdebug("waking map %p for %pI4\n",
+	  map, &map->m_addr);
+	rds_stats_inc(s_cong_update_received);
+	atomic_inc(&rds_cong_generation);
+	if (wq_has_sleeper(&map->m_waitq))
+		wake_up(&map->m_waitq);
+	if (wq_has_sleeper(&rds_poll_waitq))
+		wake_up_all(&rds_poll_waitq);
+
+	if (portmask && !list_empty(&rds_cong_monitor)) {
+		unsigned long flags;
+		struct rds_sock *rs;
+
+		read_lock_irqsave(&rds_cong_monitor_lock, flags);
+		list_for_each_entry(rs, &rds_cong_monitor, rs_cong_list) {
+			spin_lock(&rs->rs_lock);
+			rs->rs_cong_notify |= (rs->rs_cong_mask & portmask);
+			rs->rs_cong_mask &= ~portmask;
+			spin_unlock(&rs->rs_lock);
+			if (rs->rs_cong_notify)
+				rds_wake_sk_sleep(rs);
+		}
+		read_unlock_irqrestore(&rds_cong_monitor_lock, flags);
+	}
+}
+EXPORT_SYMBOL_GPL(rds_cong_map_updated);
+
+int rds_cong_updated_since(unsigned long *recent)
+{
+	unsigned long gen = atomic_read(&rds_cong_generation);
+
+	if (likely(*recent == gen))
+		return 0;
+	*recent = gen;
+	return 1;
+}
+
+/*
+ * We're called under the locking that protects the sockets receive buffer
+ * consumption.  This makes it a lot easier for the caller to only call us
+ * when it knows that an existing set bit needs to be cleared, and vice versa.
+ * We can't block and we need to deal with concurrent sockets working against
+ * the same per-address map.
+ */
+void rds_cong_set_bit(struct rds_cong_map *map, __be16 port)
+{
+	unsigned long i;
+	unsigned long off;
+
+	rdsdebug("setting congestion for %pI4:%u in map %p\n",
+	  &map->m_addr, ntohs(port), map);
+
+	i = be16_to_cpu(port) / RDS_CONG_MAP_PAGE_BITS;
+	off = be16_to_cpu(port) % RDS_CONG_MAP_PAGE_BITS;
+
+	set_bit_le(off, (void *)map->m_page_addrs[i]);
+}
+
+void rds_cong_clear_bit(struct rds_cong_map *map, __be16 port)
+{
+	unsigned long i;
+	unsigned long off;
+
+	rdsdebug("clearing congestion for %pI4:%u in map %p\n",
+	  &map->m_addr, ntohs(port), map);
+
+	i = be16_to_cpu(port) / RDS_CONG_MAP_PAGE_BITS;
+	off = be16_to_cpu(port) % RDS_CONG_MAP_PAGE_BITS;
+
+	clear_bit_le(off, (void *)map->m_page_addrs[i]);
+}
+
+static int rds_cong_test_bit(struct rds_cong_map *map, __be16 port)
+{
+	unsigned long i;
+	unsigned long off;
+
+	i = be16_to_cpu(port) / RDS_CONG_MAP_PAGE_BITS;
+	off = be16_to_cpu(port) % RDS_CONG_MAP_PAGE_BITS;
+
+	return test_bit_le(off, (void *)map->m_page_addrs[i]);
+}
+
+void rds_cong_add_socket(struct rds_sock *rs)
+{
+	unsigned long flags;
+
+	write_lock_irqsave(&rds_cong_monitor_lock, flags);
+	if (list_empty(&rs->rs_cong_list))
+		list_add(&rs->rs_cong_list, &rds_cong_monitor);
+	write_unlock_irqrestore(&rds_cong_monitor_lock, flags);
+}
+
+void rds_cong_remove_socket(struct rds_sock *rs)
+{
+	unsigned long flags;
+	struct rds_cong_map *map;
+
+	write_lock_irqsave(&rds_cong_monitor_lock, flags);
+	list_del_init(&rs->rs_cong_list);
+	write_unlock_irqrestore(&rds_cong_monitor_lock, flags);
+
+	/* update congestion map for now-closed port */
+	spin_lock_irqsave(&rds_cong_lock, flags);
+	map = rds_cong_tree_walk(&rs->rs_bound_addr, NULL);
+	spin_unlock_irqrestore(&rds_cong_lock, flags);
+
+	if (map && rds_cong_test_bit(map, rs->rs_bound_port)) {
+		rds_cong_clear_bit(map, rs->rs_bound_port);
+		rds_cong_queue_updates(map);
+	}
+}
+
+int rds_cong_wait(struct rds_cong_map *map, __be16 port, int nonblock,
+		  struct rds_sock *rs)
+{
+	if (!rds_cong_test_bit(map, port))
+		return 0;
+	if (nonblock) {
+		if (rs && rs->rs_cong_monitor) {
+			unsigned long flags;
+
+			/* It would have been nice to have an atomic set_bit on
+			 * a uint64_t. */
+			spin_lock_irqsave(&rs->rs_lock, flags);
+			rs->rs_cong_mask |= RDS_CONG_MONITOR_MASK(ntohs(port));
+			spin_unlock_irqrestore(&rs->rs_lock, flags);
+
+			/* Test again - a congestion update may have arrived in
+			 * the meantime. */
+			if (!rds_cong_test_bit(map, port))
+				return 0;
+		}
+		rds_stats_inc(s_cong_send_error);
+		return -ENOBUFS;
+	}
+
+	rds_stats_inc(s_cong_send_blocked);
+	rdsdebug("waiting on map %p for port %u\n", map, be16_to_cpu(port));
+
+	return wait_event_interruptible(map->m_waitq,
+					!rds_cong_test_bit(map, port));
+}
+
+void rds_cong_exit(void)
+{
+	struct rb_node *node;
+	struct rds_cong_map *map;
+	unsigned long i;
+
+	while ((node = rb_first(&rds_cong_tree))) {
+		map = rb_entry(node, struct rds_cong_map, m_rb_node);
+		rdsdebug("freeing map %p\n", map);
+		rb_erase(&map->m_rb_node, &rds_cong_tree);
+		for (i = 0; i < RDS_CONG_MAP_PAGES && map->m_page_addrs[i]; i++)
+			free_page(map->m_page_addrs[i]);
+		kfree(map);
+	}
+}
+
+/*
+ * Allocate a RDS message containing a congestion update.
+ */
+struct rds_message *rds_cong_update_alloc(struct rds_connection *conn)
+{
+	struct rds_cong_map *map = conn->c_lcong;
+	struct rds_message *rm;
+
+	rm = rds_message_map_pages(map->m_page_addrs, RDS_CONG_MAP_BYTES);
+	if (!IS_ERR(rm))
+		rm->m_inc.i_hdr.h_flags = RDS_FLAG_CONG_BITMAP;
+
+	return rm;
+}