Pull tracing fixes from Steven Rostedt:
 "A few tracing fixes:

   - Remove lockdown from tracefs itself and moved it to the trace
     directory. Have the open functions there do the lockdown checks.

   - Fix a few races with opening an instance file and the instance
     being deleted (Discovered during the lockdown updates). Kept
     separate from the clean up code such that they can be backported to
     stable easier.

   - Clean up and consolidated the checks done when opening a trace
     file, as there were multiple checks that need to be done, and it
     did not make sense having them done in each open instance.

   - Fix a regression in the record mcount code.

   - Small hw_lat detector tracer fixes.

   - A trace_pipe read fix due to not initializing trace_seq"

* tag 'trace-v5.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Initialize iter->seq after zeroing in tracing_read_pipe()
  tracing/hwlat: Don't ignore outer-loop duration when calculating max_latency
  tracing/hwlat: Report total time spent in all NMIs during the sample
  recordmcount: Fix nop_mcount() function
  tracing: Do not create tracefs files if tracefs lockdown is in effect
  tracing: Add locked_down checks to the open calls of files created for tracefs
  tracing: Add tracing_check_open_get_tr()
  tracing: Have trace events system open call tracing_open_generic_tr()
  tracing: Get trace_array reference for available_tracers files
  ftrace: Get a reference counter for the trace_array on filter files
  tracefs: Revert ccbd54ff54e8 ("tracefs: Restrict tracefs when the kernel is locked down")

The removal of the longjmp code in recordmcount.c mistakenly made the return
of make_nop() being negative an exit of nop_mcount(). It should not exit the
routine, but instead just not process that part of the code. By exiting with
an error code, it would cause the update of recordmcount to fail some files
which would fail the build if ftrace function tracing was enabled.

Link: http://lkml.kernel.org/r/20191009110538.5909fec6@gandalf.local.home

Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Fixes: 3f1df12019f3 ("recordmcount: Rewrite error/success handling")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pull module fixes from Jessica Yu:
 "Code cleanups and kbuild/namespace related fixups from Masahiro.

  Most importantly, it fixes a namespace-related modpost issue for
  external module builds

   - Fix broken external module builds due to a modpost bug in
     read_dump(), where the namespace was not being strdup'd and
     sym->namespace would be set to bogus data.

   - Various namespace-related kbuild fixes and cleanups thanks to
     Masahiro Yamada"

* tag 'modules-for-v5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
  doc: move namespaces.rst from kbuild/ to core-api/
  nsdeps: make generated patches independent of locale
  nsdeps: fix hashbang of scripts/nsdeps
  kbuild: fix build error of 'make nsdeps' in clean tree
  module: rename __kstrtab_ns_* to __kstrtabns_* to avoid symbol conflict
  modpost: fix broken sym->namespace for external module builds
  module: swap the order of symbol.namespace
  scripts: add_namespace: Fix coccicheck failed

scripts/nsdeps automatically generates a patch to add MODULE_IMPORT_NS
tags, and what is nicer, it sorts the lines alphabetically with the
'sort' command. However, the output from the 'sort' command depends on
locale.

For example, I got this:

$ { echo usbstorage; echo usb_storage; } | LANG=en_US.UTF-8 sort
usbstorage
usb_storage
$ { echo usbstorage; echo usb_storage; } | LANG=C sort
usb_storage
usbstorage

So, this means people might potentially send different patches.

This kind of issue was reported in the past, for example,
commit f55f2328bb28 ("kbuild: make sorting initramfs contents
independent of locale").

Adding 'LANG=C' is a conventional way of fixing when a deterministic
result is desirable.

I added 'LANG=C' very close to the 'sort' command since changing
locale affects the language of error messages etc. We should respect
users' choice as much as possible.

Reviewed-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>

This script does not use bash-extension. I am guessing this hashbang
was copied from scripts/coccicheck, which really uses bash-extension.

/bin/sh is enough for this script.

Reviewed-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>

Currently, external module builds produce tons of false-positives:

  WARNING: module <mod> uses symbol <sym> from namespace <ns>, but does not import it.

Here, the <ns> part shows a random string.

When you build external modules, the symbol info of vmlinux and
in-kernel modules are read from $(objtree)/Module.symvers, but
read_dump() is buggy in multiple ways:

[1] When the modpost is run for vmlinux and in-kernel modules,
sym_extract_namespace() allocates memory for the namespace. On the
other hand, read_dump() does not, then sym->namespace will point to
somewhere in the line buffer of get_next_line(). The data in the
buffer will be replaced soon, and sym->namespace will end up with
pointing to unrelated data. As a result, check_exports() will show
random strings in the warning messages.

[2] When there is no namespace, sym_extract_namespace() returns NULL.
On the other hand, read_dump() sets namespace to an empty string "".
(but, it will be later replaced with unrelated data due to bug [1].)
The check_exports() shows a warning unless exp->namespace is NULL,
so every symbol read from read_dump() emits the warning, which is
mostly false positive.

To address [1], sym_add_exported() calls strdup() for s->namespace.
The namespace from sym_extract_namespace() must be freed to avoid
memory leak.

For [2], I changed the if-conditional in check_exports().

This commit also fixes sym_add_exported() to set s->namespace correctly
when the symbol is preloaded.

Reviewed-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>

Currently, EXPORT_SYMBOL_NS(_GPL) constructs the kernel symbol as
follows:

  __ksymtab_SYMBOL.NAMESPACE

The sym_extract_namespace() in modpost allocates memory for the part
SYMBOL.NAMESPACE when '.' is contained. One problem is that the pointer
returned by strdup() is lost because the symbol name will be copied to
malloc'ed memory by alloc_symbol(). No one will keep track of the
pointer of strdup'ed memory.

sym->namespace still points to the NAMESPACE part. So, you can free it
with complicated code like this:

   free(sym->namespace - strlen(sym->name) - 1);

It complicates memory free.

To fix it elegantly, I swapped the order of the symbol and the
namespace as follows:

  __ksymtab_NAMESPACE.SYMBOL

then, simplified sym_extract_namespace() so that it allocates memory
only for the NAMESPACE part.

I prefer this order because it is intuitive and also matches to major
languages. For example, NAMESPACE::NAME in C++, MODULE.NAME in Python.

Reviewed-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>

Now all scripts in scripts/coccinelle to be automatically called
by coccicheck. However new adding add_namespace.cocci does not
support report mode, which make coccicheck failed.
This add "virtual report" to  make the coccicheck go ahead smoothly.

Fixes: eb8305aecb95 ("scripts: Coccinelle script for namespace dependencies.")
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Acked-by: Matthias Maennich <maennich@google.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>

Geert Uytterhoeven reports a strange side-effect of commit 858805b336be
("kbuild: add $(BASH) to run scripts with bash-extension"), which
inserts the contents of a localversion file in the build directory twice.

[Steps to Reproduce]
  $ echo bar > localversion
  $ mkdir build
  $ cd build/
  $ echo foo > localversion
  $ make -s -f ../Makefile defconfig include/config/kernel.release
  $ cat include/config/kernel.release
  5.4.0-rc1foofoobar

This comes down to the behavior change of local variables.

The 'man sh' on my Ubuntu machine, where sh is an alias to dash,
explains as follows:
  When a variable is made local, it inherits the initial value and
  exported and readonly flags from the variable with the same name
  in the surrounding scope, if there is one. Otherwise, the variable
  is initially unset.

[Test Code]

  foo ()
  {
          local res
          echo "res: $res"
  }

  res=1
  foo

[Result]

  $ sh test.sh
  res: 1
  $ bash test.sh
  res:

So, scripts/setlocalversion correctly works only for bash in spite of
its hashbang being #!/bin/sh. Nobody had noticed it before because
CONFIG_SHELL was previously set to bash almost all the time.

Now that CONFIG_SHELL is set to sh, we must write portable and correct
code. I gave the Fixes tag to the commit that uncovered the issue.

Clear the variable 'res' in collect_files() to make it work for sh
(and it also works on distributions where sh is an alias to bash).

Fixes: 858805b336be ("kbuild: add $(BASH) to run scripts with bash-extension")
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

The namespace.pl script does not work properly if objtree is not set to
an absolute path. The do_nm function is run from within the find
function, which changes directories.

Because of this, appending objtree, $File::Find::dir, and $source, will
return a path which is not valid from the current directory.

This used to work when objtree was set to an absolute path when using
"make namespacecheck". It appears to have not worked when calling
./scripts/namespace.pl directly.

This behavior was changed in 7e1c04779efd ("kbuild: Use relative path
for $(objtree)", 2014-05-14)

Rather than fixing the Makefile to set objtree to an absolute path, just
fix namespace.pl to work when srctree and objtree are relative. Also fix
the script to use an absolute path for these by default.

Use the File::Spec module for this purpose. It's been part of perl
5 since 5.005.

The curdir() function is used to get the current directory when the
objtree and srctree aren't set in the environment.

rel2abs() is used to convert possibly relative objtree and srctree
environment variables to absolute paths.

Finally, the catfile() function is used instead of string appending
paths together, since this is more robust when joining paths together.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>