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, 269 insertions, 0 deletions

diff --git a/drivers/net/arcnet/capmode.c b/drivers/net/arcnet/capmode.c
new file mode 100644
index 000000000..7a0a79973
--- /dev/null
+++ b/drivers/net/arcnet/capmode.c
@@ -0,0 +1,269 @@
+/*
+ * Linux ARCnet driver - "cap mode" packet encapsulation.
+ * It adds sequence numbers to packets for communicating between a user space
+ * application and the driver. After a transmit it sends a packet with protocol
+ * byte 0 back up to the userspace containing the sequence number of the packet
+ * plus the transmit-status on the ArcNet.
+ *
+ * Written 2002-4 by Esben Nielsen, Vestas Wind Systems A/S
+ * Derived from arc-rawmode.c by Avery Pennarun.
+ * arc-rawmode was in turned based on skeleton.c, see below.
+ *
+ * **********************
+ *
+ * The original copyright of skeleton.c was as follows:
+ *
+ * skeleton.c Written 1993 by Donald Becker.
+ * Copyright 1993 United States Government as represented by the
+ * Director, National Security Agency.  This software may only be used
+ * and distributed according to the terms of the GNU General Public License as
+ * modified by SRC, incorporated herein by reference.
+ *
+ * **********************
+ *
+ * For more details, see drivers/net/arcnet.c
+ *
+ * **********************
+ */
+
+#define pr_fmt(fmt) "arcnet:" KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/gfp.h>
+#include <linux/init.h>
+#include <linux/if_arp.h>
+#include <net/arp.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+
+#include "arcdevice.h"
+
+/* packet receiver */
+static void rx(struct net_device *dev, int bufnum,
+	       struct archdr *pkthdr, int length)
+{
+	struct arcnet_local *lp = netdev_priv(dev);
+	struct sk_buff *skb;
+	struct archdr *pkt;
+	char *pktbuf, *pkthdrbuf;
+	int ofs;
+
+	arc_printk(D_DURING, dev, "it's a raw(cap) packet (length=%d)\n",
+		   length);
+
+	if (length >= MinTU)
+		ofs = 512 - length;
+	else
+		ofs = 256 - length;
+
+	skb = alloc_skb(length + ARC_HDR_SIZE + sizeof(int), GFP_ATOMIC);
+	if (!skb) {
+		dev->stats.rx_dropped++;
+		return;
+	}
+	skb_put(skb, length + ARC_HDR_SIZE + sizeof(int));
+	skb->dev = dev;
+	skb_reset_mac_header(skb);
+	pkt = (struct archdr *)skb_mac_header(skb);
+	skb_pull(skb, ARC_HDR_SIZE);
+
+	/* up to sizeof(pkt->soft) has already been copied from the card
+	 * squeeze in an int for the cap encapsulation
+	 * use these variables to be sure we count in bytes, not in
+	 * sizeof(struct archdr)
+	 */
+	pktbuf = (char *)pkt;
+	pkthdrbuf = (char *)pkthdr;
+	memcpy(pktbuf, pkthdrbuf, ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto));
+	memcpy(pktbuf + ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto) + sizeof(int),
+	       pkthdrbuf + ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto),
+	       sizeof(struct archdr) - ARC_HDR_SIZE - sizeof(pkt->soft.cap.proto));
+
+	if (length > sizeof(pkt->soft))
+		lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
+				      pkt->soft.raw + sizeof(pkt->soft)
+				      + sizeof(int),
+				      length - sizeof(pkt->soft));
+
+	if (BUGLVL(D_SKB))
+		arcnet_dump_skb(dev, skb, "rx");
+
+	skb->protocol = cpu_to_be16(ETH_P_ARCNET);
+	netif_rx(skb);
+}
+
+/* Create the ARCnet hard/soft headers for cap mode.
+ * There aren't any soft headers in cap mode - not even the protocol id.
+ */
+static int build_header(struct sk_buff *skb,
+			struct net_device *dev,
+			unsigned short type,
+			uint8_t daddr)
+{
+	int hdr_size = ARC_HDR_SIZE;
+	struct archdr *pkt = skb_push(skb, hdr_size);
+
+	arc_printk(D_PROTO, dev, "Preparing header for cap packet %x.\n",
+		   *((int *)&pkt->soft.cap.cookie[0]));
+
+	/* Set the source hardware address.
+	 *
+	 * This is pretty pointless for most purposes, but it can help in
+	 * debugging.  ARCnet does not allow us to change the source address in
+	 * the actual packet sent)
+	 */
+	pkt->hard.source = *dev->dev_addr;
+
+	/* see linux/net/ethernet/eth.c to see where I got the following */
+
+	if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
+		/* FIXME: fill in the last byte of the dest ipaddr here to
+		 * better comply with RFC1051 in "noarp" mode.
+		 */
+		pkt->hard.dest = 0;
+		return hdr_size;
+	}
+	/* otherwise, just fill it in and go! */
+	pkt->hard.dest = daddr;
+
+	return hdr_size;	/* success */
+}
+
+static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
+		      int bufnum)
+{
+	struct arcnet_local *lp = netdev_priv(dev);
+	struct arc_hardware *hard = &pkt->hard;
+	int ofs;
+
+	/* hard header is not included in packet length */
+	length -= ARC_HDR_SIZE;
+	/* And neither is the cookie field */
+	length -= sizeof(int);
+
+	arc_printk(D_DURING, dev, "prepare_tx: txbufs=%d/%d/%d\n",
+		   lp->next_tx, lp->cur_tx, bufnum);
+
+	arc_printk(D_PROTO, dev, "Sending for cap packet %x.\n",
+		   *((int *)&pkt->soft.cap.cookie[0]));
+
+	if (length > XMTU) {
+		/* should never happen! other people already check for this. */
+		arc_printk(D_NORMAL, dev, "Bug!  prepare_tx with size %d (> %d)\n",
+			   length, XMTU);
+		length = XMTU;
+	}
+	if (length > MinTU) {
+		hard->offset[0] = 0;
+		hard->offset[1] = ofs = 512 - length;
+	} else if (length > MTU) {
+		hard->offset[0] = 0;
+		hard->offset[1] = ofs = 512 - length - 3;
+	} else {
+		hard->offset[0] = ofs = 256 - length;
+	}
+
+	arc_printk(D_DURING, dev, "prepare_tx: length=%d ofs=%d\n",
+		   length, ofs);
+
+	/* Copy the arcnet-header + the protocol byte down: */
+	lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
+	lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft.cap.proto,
+			    sizeof(pkt->soft.cap.proto));
+
+	/* Skip the extra integer we have written into it as a cookie
+	 * but write the rest of the message:
+	 */
+	lp->hw.copy_to_card(dev, bufnum, ofs + 1,
+			    ((unsigned char *)&pkt->soft.cap.mes), length - 1);
+
+	lp->lastload_dest = hard->dest;
+
+	return 1;	/* done */
+}
+
+static int ack_tx(struct net_device *dev, int acked)
+{
+	struct arcnet_local *lp = netdev_priv(dev);
+	struct sk_buff *ackskb;
+	struct archdr *ackpkt;
+	int length = sizeof(struct arc_cap);
+
+	arc_printk(D_DURING, dev, "capmode: ack_tx: protocol: %x: result: %d\n",
+		   lp->outgoing.skb->protocol, acked);
+
+	if (BUGLVL(D_SKB))
+		arcnet_dump_skb(dev, lp->outgoing.skb, "ack_tx");
+
+	/* Now alloc a skb to send back up through the layers: */
+	ackskb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC);
+	if (!ackskb)
+		goto free_outskb;
+
+	skb_put(ackskb, length + ARC_HDR_SIZE);
+	ackskb->dev = dev;
+
+	skb_reset_mac_header(ackskb);
+	ackpkt = (struct archdr *)skb_mac_header(ackskb);
+	/* skb_pull(ackskb, ARC_HDR_SIZE); */
+
+	skb_copy_from_linear_data(lp->outgoing.skb, ackpkt,
+				  ARC_HDR_SIZE + sizeof(struct arc_cap));
+	ackpkt->soft.cap.proto = 0; /* using protocol 0 for acknowledge */
+	ackpkt->soft.cap.mes.ack = acked;
+
+	arc_printk(D_PROTO, dev, "Acknowledge for cap packet %x.\n",
+		   *((int *)&ackpkt->soft.cap.cookie[0]));
+
+	ackskb->protocol = cpu_to_be16(ETH_P_ARCNET);
+
+	if (BUGLVL(D_SKB))
+		arcnet_dump_skb(dev, ackskb, "ack_tx_recv");
+	netif_rx(ackskb);
+
+free_outskb:
+	dev_kfree_skb_irq(lp->outgoing.skb);
+	lp->outgoing.proto = NULL;
+			/* We are always finished when in this protocol */
+
+	return 0;
+}
+
+static struct ArcProto capmode_proto = {
+	.suffix		= 'r',
+	.mtu		= XMTU,
+	.rx		= rx,
+	.build_header	= build_header,
+	.prepare_tx	= prepare_tx,
+	.ack_tx		= ack_tx
+};
+
+static int __init capmode_module_init(void)
+{
+	int count;
+
+	pr_info("cap mode (`c') encapsulation support loaded\n");
+
+	for (count = 1; count <= 8; count++)
+		if (arc_proto_map[count] == arc_proto_default)
+			arc_proto_map[count] = &capmode_proto;
+
+	/* for cap mode, we only set the bcast proto if there's no better one */
+	if (arc_bcast_proto == arc_proto_default)
+		arc_bcast_proto = &capmode_proto;
+
+	arc_proto_default = &capmode_proto;
+	arc_raw_proto = &capmode_proto;
+
+	return 0;
+}
+
+static void __exit capmode_module_exit(void)
+{
+	arcnet_unregister_proto(&capmode_proto);
+}
+module_init(capmode_module_init);
+module_exit(capmode_module_exit);
+
+MODULE_DESCRIPTION("ARCnet CAP mode packet interface module");
+MODULE_LICENSE("GPL");