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, 189 insertions, 0 deletions

diff --git a/Documentation/networking/ipvlan.rst b/Documentation/networking/ipvlan.rst
new file mode 100644
index 000000000..895d0ccfd
--- /dev/null
+++ b/Documentation/networking/ipvlan.rst
@@ -0,0 +1,189 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===================
+IPVLAN Driver HOWTO
+===================
+
+Initial Release:
+	Mahesh Bandewar <maheshb AT google.com>
+
+1. Introduction:
+================
+This is conceptually very similar to the macvlan driver with one major
+exception of using L3 for mux-ing /demux-ing among slaves. This property makes
+the master device share the L2 with its slave devices. I have developed this
+driver in conjunction with network namespaces and not sure if there is use case
+outside of it.
+
+
+2. Building and Installation:
+=============================
+
+In order to build the driver, please select the config item CONFIG_IPVLAN.
+The driver can be built into the kernel (CONFIG_IPVLAN=y) or as a module
+(CONFIG_IPVLAN=m).
+
+
+3. Configuration:
+=================
+
+There are no module parameters for this driver and it can be configured
+using IProute2/ip utility.
+::
+
+    ip link add link <master> name <slave> type ipvlan [ mode MODE ] [ FLAGS ]
+       where
+	 MODE: l3 (default) | l3s | l2
+	 FLAGS: bridge (default) | private | vepa
+
+e.g.
+
+    (a) Following will create IPvlan link with eth0 as master in
+	L3 bridge mode::
+
+	  bash# ip link add link eth0 name ipvl0 type ipvlan
+    (b) This command will create IPvlan link in L2 bridge mode::
+
+	  bash# ip link add link eth0 name ipvl0 type ipvlan mode l2 bridge
+
+    (c) This command will create an IPvlan device in L2 private mode::
+
+	  bash# ip link add link eth0 name ipvlan type ipvlan mode l2 private
+
+    (d) This command will create an IPvlan device in L2 vepa mode::
+
+	  bash# ip link add link eth0 name ipvlan type ipvlan mode l2 vepa
+
+
+4. Operating modes:
+===================
+
+IPvlan has two modes of operation - L2 and L3. For a given master device,
+you can select one of these two modes and all slaves on that master will
+operate in the same (selected) mode. The RX mode is almost identical except
+that in L3 mode the slaves won't receive any multicast / broadcast traffic.
+L3 mode is more restrictive since routing is controlled from the other (mostly)
+default namespace.
+
+4.1 L2 mode:
+------------
+
+In this mode TX processing happens on the stack instance attached to the
+slave device and packets are switched and queued to the master device to send
+out. In this mode the slaves will RX/TX multicast and broadcast (if applicable)
+as well.
+
+4.2 L3 mode:
+------------
+
+In this mode TX processing up to L3 happens on the stack instance attached
+to the slave device and packets are switched to the stack instance of the
+master device for the L2 processing and routing from that instance will be
+used before packets are queued on the outbound device. In this mode the slaves
+will not receive nor can send multicast / broadcast traffic.
+
+4.3 L3S mode:
+-------------
+
+This is very similar to the L3 mode except that iptables (conn-tracking)
+works in this mode and hence it is L3-symmetric (L3s). This will have slightly less
+performance but that shouldn't matter since you are choosing this mode over plain-L3
+mode to make conn-tracking work.
+
+5. Mode flags:
+==============
+
+At this time following mode flags are available
+
+5.1 bridge:
+-----------
+This is the default option. To configure the IPvlan port in this mode,
+user can choose to either add this option on the command-line or don't specify
+anything. This is the traditional mode where slaves can cross-talk among
+themselves apart from talking through the master device.
+
+5.2 private:
+------------
+If this option is added to the command-line, the port is set in private
+mode. i.e. port won't allow cross communication between slaves.
+
+5.3 vepa:
+---------
+If this is added to the command-line, the port is set in VEPA mode.
+i.e. port will offload switching functionality to the external entity as
+described in 802.1Qbg
+Note: VEPA mode in IPvlan has limitations. IPvlan uses the mac-address of the
+master-device, so the packets which are emitted in this mode for the adjacent
+neighbor will have source and destination mac same. This will make the switch /
+router send the redirect message.
+
+6. What to choose (macvlan vs. ipvlan)?
+=======================================
+
+These two devices are very similar in many regards and the specific use
+case could very well define which device to choose. if one of the following
+situations defines your use case then you can choose to use ipvlan:
+
+
+(a) The Linux host that is connected to the external switch / router has
+    policy configured that allows only one mac per port.
+(b) No of virtual devices created on a master exceed the mac capacity and
+    puts the NIC in promiscuous mode and degraded performance is a concern.
+(c) If the slave device is to be put into the hostile / untrusted network
+    namespace where L2 on the slave could be changed / misused.
+
+
+6. Example configuration:
+=========================
+
+::
+
+  +=============================================================+
+  |  Host: host1                                                |
+  |                                                             |
+  |   +----------------------+      +----------------------+    |
+  |   |   NS:ns0             |      |  NS:ns1              |    |
+  |   |                      |      |                      |    |
+  |   |                      |      |                      |    |
+  |   |        ipvl0         |      |         ipvl1        |    |
+  |   +----------#-----------+      +-----------#----------+    |
+  |              #                              #               |
+  |              ################################               |
+  |                              # eth0                         |
+  +==============================#==============================+
+
+
+(a) Create two network namespaces - ns0, ns1::
+
+	ip netns add ns0
+	ip netns add ns1
+
+(b) Create two ipvlan slaves on eth0 (master device)::
+
+	ip link add link eth0 ipvl0 type ipvlan mode l2
+	ip link add link eth0 ipvl1 type ipvlan mode l2
+
+(c) Assign slaves to the respective network namespaces::
+
+	ip link set dev ipvl0 netns ns0
+	ip link set dev ipvl1 netns ns1
+
+(d) Now switch to the namespace (ns0 or ns1) to configure the slave devices
+
+	- For ns0::
+
+		(1) ip netns exec ns0 bash
+		(2) ip link set dev ipvl0 up
+		(3) ip link set dev lo up
+		(4) ip -4 addr add 127.0.0.1 dev lo
+		(5) ip -4 addr add $IPADDR dev ipvl0
+		(6) ip -4 route add default via $ROUTER dev ipvl0
+
+	- For ns1::
+
+		(1) ip netns exec ns1 bash
+		(2) ip link set dev ipvl1 up
+		(3) ip link set dev lo up
+		(4) ip -4 addr add 127.0.0.1 dev lo
+		(5) ip -4 addr add $IPADDR dev ipvl1
+		(6) ip -4 route add default via $ROUTER dev ipvl1