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, 132 insertions, 0 deletions

diff --git a/Documentation/usb/acm.rst b/Documentation/usb/acm.rst
new file mode 100644
index 000000000..e8bda98e9
--- /dev/null
+++ b/Documentation/usb/acm.rst
@@ -0,0 +1,132 @@
+======================
+Linux ACM driver v0.16
+======================
+
+Copyright (c) 1999 Vojtech Pavlik <vojtech@suse.cz>
+
+Sponsored by SuSE
+
+0. Disclaimer
+~~~~~~~~~~~~~
+This program is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 2 of the License, or (at your option)
+any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+more details.
+
+You should have received a copy of the GNU General Public License along
+with this program; if not, write to the Free Software Foundation, Inc., 59
+Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+Should you need to contact me, the author, you can do so either by e-mail -
+mail your message to <vojtech@suse.cz>, or by paper mail: Vojtech Pavlik,
+Ucitelska 1576, Prague 8, 182 00 Czech Republic
+
+For your convenience, the GNU General Public License version 2 is included
+in the package: See the file COPYING.
+
+1. Usage
+~~~~~~~~
+The drivers/usb/class/cdc-acm.c drivers works with USB modems and USB ISDN terminal
+adapters that conform to the Universal Serial Bus Communication Device Class
+Abstract Control Model (USB CDC ACM) specification.
+
+Many modems do, here is a list of those I know of:
+
+	- 3Com OfficeConnect 56k
+	- 3Com Voice FaxModem Pro
+	- 3Com Sportster
+	- MultiTech MultiModem 56k
+	- Zoom 2986L FaxModem
+	- Compaq 56k FaxModem
+	- ELSA Microlink 56k
+
+I know of one ISDN TA that does work with the acm driver:
+
+	- 3Com USR ISDN Pro TA
+
+Some cell phones also connect via USB. I know the following phones work:
+
+	- SonyEricsson K800i
+
+Unfortunately many modems and most ISDN TAs use proprietary interfaces and
+thus won't work with this drivers. Check for ACM compliance before buying.
+
+To use the modems you need these modules loaded::
+
+	usbcore.ko
+	uhci-hcd.ko ohci-hcd.ko or ehci-hcd.ko
+	cdc-acm.ko
+
+After that, the modem[s] should be accessible. You should be able to use
+minicom, ppp and mgetty with them.
+
+2. Verifying that it works
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The first step would be to check /sys/kernel/debug/usb/devices, it should look
+like this::
+
+  T:  Bus=01 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#=  1 Spd=12  MxCh= 2
+  B:  Alloc=  0/900 us ( 0%), #Int=  0, #Iso=  0
+  D:  Ver= 1.00 Cls=09(hub  ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
+  P:  Vendor=0000 ProdID=0000 Rev= 0.00
+  S:  Product=USB UHCI Root Hub
+  S:  SerialNumber=6800
+  C:* #Ifs= 1 Cfg#= 1 Atr=40 MxPwr=  0mA
+  I:  If#= 0 Alt= 0 #EPs= 1 Cls=09(hub  ) Sub=00 Prot=00 Driver=hub
+  E:  Ad=81(I) Atr=03(Int.) MxPS=   8 Ivl=255ms
+  T:  Bus=01 Lev=01 Prnt=01 Port=01 Cnt=01 Dev#=  2 Spd=12  MxCh= 0
+  D:  Ver= 1.00 Cls=02(comm.) Sub=00 Prot=00 MxPS= 8 #Cfgs=  2
+  P:  Vendor=04c1 ProdID=008f Rev= 2.07
+  S:  Manufacturer=3Com Inc.
+  S:  Product=3Com U.S. Robotics Pro ISDN TA
+  S:  SerialNumber=UFT53A49BVT7
+  C:  #Ifs= 1 Cfg#= 1 Atr=60 MxPwr=  0mA
+  I:  If#= 0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=acm
+  E:  Ad=85(I) Atr=02(Bulk) MxPS=  64 Ivl=  0ms
+  E:  Ad=04(O) Atr=02(Bulk) MxPS=  64 Ivl=  0ms
+  E:  Ad=81(I) Atr=03(Int.) MxPS=  16 Ivl=128ms
+  C:* #Ifs= 2 Cfg#= 2 Atr=60 MxPwr=  0mA
+  I:  If#= 0 Alt= 0 #EPs= 1 Cls=02(comm.) Sub=02 Prot=01 Driver=acm
+  E:  Ad=81(I) Atr=03(Int.) MxPS=  16 Ivl=128ms
+  I:  If#= 1 Alt= 0 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=acm
+  E:  Ad=85(I) Atr=02(Bulk) MxPS=  64 Ivl=  0ms
+  E:  Ad=04(O) Atr=02(Bulk) MxPS=  64 Ivl=  0ms
+
+The presence of these three lines (and the Cls= 'comm' and 'data' classes)
+is important, it means it's an ACM device. The Driver=acm means the acm
+driver is used for the device. If you see only Cls=ff(vend.) then you're out
+of luck, you have a device with vendor specific-interface::
+
+  D:  Ver= 1.00 Cls=02(comm.) Sub=00 Prot=00 MxPS= 8 #Cfgs=  2
+  I:  If#= 0 Alt= 0 #EPs= 1 Cls=02(comm.) Sub=02 Prot=01 Driver=acm
+  I:  If#= 1 Alt= 0 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=acm
+
+In the system log you should see::
+
+  usb.c: USB new device connect, assigned device number 2
+  usb.c: kmalloc IF c7691fa0, numif 1
+  usb.c: kmalloc IF c7b5f3e0, numif 2
+  usb.c: skipped 4 class/vendor specific interface descriptors
+  usb.c: new device strings: Mfr=1, Product=2, SerialNumber=3
+  usb.c: USB device number 2 default language ID 0x409
+  Manufacturer: 3Com Inc.
+  Product: 3Com U.S. Robotics Pro ISDN TA
+  SerialNumber: UFT53A49BVT7
+  acm.c: probing config 1
+  acm.c: probing config 2
+  ttyACM0: USB ACM device
+  acm.c: acm_control_msg: rq: 0x22 val: 0x0 len: 0x0 result: 0
+  acm.c: acm_control_msg: rq: 0x20 val: 0x0 len: 0x7 result: 7
+  usb.c: acm driver claimed interface c7b5f3e0
+  usb.c: acm driver claimed interface c7b5f3f8
+  usb.c: acm driver claimed interface c7691fa0
+
+If all this seems to be OK, fire up minicom and set it to talk to the ttyACM
+device and try typing 'at'. If it responds with 'OK', then everything is
+working.