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, 163 insertions, 0 deletions

diff --git a/Documentation/process/kernel-enforcement-statement.rst b/Documentation/process/kernel-enforcement-statement.rst
new file mode 100644
index 000000000..dc2d813b2
--- /dev/null
+++ b/Documentation/process/kernel-enforcement-statement.rst
@@ -0,0 +1,163 @@
+.. _process_statement_kernel:
+
+Linux Kernel Enforcement Statement
+----------------------------------
+
+As developers of the Linux kernel, we have a keen interest in how our software
+is used and how the license for our software is enforced.  Compliance with the
+reciprocal sharing obligations of GPL-2.0 is critical to the long-term
+sustainability of our software and community.
+
+Although there is a right to enforce the separate copyright interests in the
+contributions made to our community, we share an interest in ensuring that
+individual enforcement actions are conducted in a manner that benefits our
+community and do not have an unintended negative impact on the health and
+growth of our software ecosystem.  In order to deter unhelpful enforcement
+actions, we agree that it is in the best interests of our development
+community to undertake the following commitment to users of the Linux kernel
+on behalf of ourselves and any successors to our copyright interests:
+
+    Notwithstanding the termination provisions of the GPL-2.0, we agree that
+    it is in the best interests of our development community to adopt the
+    following provisions of GPL-3.0 as additional permissions under our
+    license with respect to any non-defensive assertion of rights under the
+    license.
+
+	However, if you cease all violation of this License, then your license
+	from a particular copyright holder is reinstated (a) provisionally,
+	unless and until the copyright holder explicitly and finally
+	terminates your license, and (b) permanently, if the copyright holder
+	fails to notify you of the violation by some reasonable means prior to
+	60 days after the cessation.
+
+	Moreover, your license from a particular copyright holder is
+	reinstated permanently if the copyright holder notifies you of the
+	violation by some reasonable means, this is the first time you have
+	received notice of violation of this License (for any work) from that
+	copyright holder, and you cure the violation prior to 30 days after
+	your receipt of the notice.
+
+Our intent in providing these assurances is to encourage more use of the
+software.  We want companies and individuals to use, modify and distribute
+this software.  We want to work with users in an open and transparent way to
+eliminate any uncertainty about our expectations regarding compliance or
+enforcement that might limit adoption of our software.  We view legal action
+as a last resort, to be initiated only when other community efforts have
+failed to resolve the problem.
+
+Finally, once a non-compliance issue is resolved, we hope the user will feel
+welcome to join us in our efforts on this project.  Working together, we will
+be stronger.
+
+Except where noted below, we speak only for ourselves, and not for any company
+we might work for today, have in the past, or will in the future.
+
+  - Laura Abbott
+  - Bjorn Andersson (Linaro)
+  - Andrea Arcangeli
+  - Neil Armstrong
+  - Jens Axboe
+  - Pablo Neira Ayuso
+  - Khalid Aziz
+  - Ralf Baechle
+  - Felipe Balbi
+  - Arnd Bergmann
+  - Ard Biesheuvel
+  - Tim Bird
+  - Paolo Bonzini
+  - Christian Borntraeger
+  - Mark Brown (Linaro)
+  - Paul Burton
+  - Javier Martinez Canillas
+  - Rob Clark
+  - Kees Cook (Google)
+  - Jonathan Corbet
+  - Dennis Dalessandro
+  - Vivien Didelot (Savoir-faire Linux)
+  - Hans de Goede
+  - Mel Gorman (SUSE)
+  - Sven Eckelmann
+  - Alex Elder (Linaro)
+  - Fabio Estevam
+  - Larry Finger
+  - Bhumika Goyal
+  - Andy Gross
+  - Juergen Gross
+  - Shawn Guo
+  - Ulf Hansson
+  - Stephen Hemminger (Microsoft)
+  - Tejun Heo
+  - Rob Herring
+  - Masami Hiramatsu
+  - Michal Hocko
+  - Simon Horman
+  - Johan Hovold (Hovold Consulting AB)
+  - Christophe JAILLET
+  - Olof Johansson
+  - Lee Jones (Linaro)
+  - Heiner Kallweit
+  - Srinivas Kandagatla
+  - Jan Kara
+  - Shuah Khan (Samsung)
+  - David Kershner
+  - Jaegeuk Kim
+  - Namhyung Kim
+  - Colin Ian King
+  - Jeff Kirsher
+  - Greg Kroah-Hartman (Linux Foundation)
+  - Christian König
+  - Vinod Koul
+  - Krzysztof Kozlowski
+  - Viresh Kumar
+  - Aneesh Kumar K.V
+  - Julia Lawall
+  - Doug Ledford
+  - Chuck Lever (Oracle)
+  - Daniel Lezcano
+  - Shaohua Li
+  - Xin Long
+  - Tony Luck
+  - Catalin Marinas (Arm Ltd)
+  - Mike Marshall
+  - Chris Mason
+  - Paul E. McKenney
+  - Arnaldo Carvalho de Melo
+  - David S. Miller
+  - Ingo Molnar
+  - Kuninori Morimoto
+  - Trond Myklebust
+  - Martin K. Petersen (Oracle)
+  - Borislav Petkov
+  - Jiri Pirko
+  - Josh Poimboeuf
+  - Sebastian Reichel (Collabora)
+  - Guenter Roeck
+  - Joerg Roedel
+  - Leon Romanovsky
+  - Steven Rostedt (VMware)
+  - Frank Rowand
+  - Ivan Safonov
+  - Anna Schumaker
+  - Jes Sorensen
+  - K.Y. Srinivasan
+  - David Sterba (SUSE)
+  - Heiko Stuebner
+  - Jiri Kosina (SUSE)
+  - Willy Tarreau
+  - Dmitry Torokhov
+  - Linus Torvalds
+  - Thierry Reding
+  - Rik van Riel
+  - Luis R. Rodriguez
+  - Geert Uytterhoeven (Glider bvba)
+  - Eduardo Valentin (Amazon.com)
+  - Daniel Vetter
+  - Linus Walleij
+  - Richard Weinberger
+  - Dan Williams
+  - Rafael J. Wysocki
+  - Arvind Yadav
+  - Masahiro Yamada
+  - Wei Yongjun
+  - Lv Zheng
+  - Marc Zyngier (Arm Ltd)