scripts/decode_stacktrace.sh: optionally use LLVM utilities

GNU's addr2line can have problems parsing a vmlinux built with LLVM,
particularly when LTO was used. In order to decode the traces correctly
this patch adds the ability to switch to LLVM's utilities readelf and
addr2line. The same approach is followed by Will in [1].

Before:
$ scripts/decode_stacktrace.sh vmlinux < kernel.log
[17716.240635] Call trace:
[17716.240646] skb_cow_data (??:?)
[17716.240654] esp6_input (ld-temp.o:?)
[17716.240666] xfrm_input (ld-temp.o:?)
[17716.240674] xfrm6_rcv (??:?)
[...]

After:
$ LLVM=1 scripts/decode_stacktrace.sh vmlinux < kernel.log
[17716.240635] Call trace:
[17716.240646] skb_cow_data (include/linux/skbuff.h:2172 net/core/skbuff.c:4503)
[17716.240654] esp6_input (net/ipv6/esp6.c:977)
[17716.240666] xfrm_input (net/xfrm/xfrm_input.c:659)
[17716.240674] xfrm6_rcv (net/ipv6/xfrm6_input.c:172)
[...]

Note that one could set CROSS_COMPILE=llvm- instead to hack around this
issue. However, doing so can break the decodecode routine as it will
force the selection of other LLVM utilities down the line e.g. llvm-as.

[1] https://lore.kernel.org/all/20230914131225.13415-3-will@kernel.org/

Link: https://lkml.kernel.org/r/20230929034836.403735-1-cmllamas@google.com
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Elliot Berman <quic_eberman@quicinc.com>
Tested-by: Justin Stitt <justinstitt@google.com>
Cc: Will Deacon <will@kernel.org>
Cc: John Stultz <jstultz@google.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Tom Rix <trix@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

scripts/decode_stacktrace.sh: strip unexpected CR from lines

When the kernel log is acquired over a serial cable it is not uncommon for
the log to contain carriage return characters, in addition to the expected
line feeds.

When this output is feed into decode_stacktrace.sh, handle_line() fails to
strip the trailing ']' off the module name, which results in find_module()
not being able to find the referred to kernel module. This is reported to
the user as:

WARNING! Modules path isn't set, but is needed to parse this symbol

The solution is to reconfigure the serial port, or to strip the carriage
returns from the log, but this isn't obvious from the error reported by
the script.

Instead, make decode_stacktrace.sh more user friendly by stripping the
trailing carriage return.

Link: https://lkml.kernel.org/r/20231225-decode-stacktrace-cr-v1-1-9f306f38cdde@quicinc.com
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

scripts: decode_stacktrace: demangle Rust symbols

Recent versions of both Binutils (`c++filt`) and LLVM (`llvm-cxxfilt`)
provide Rust v0 mangling support.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

scripts/decode_stacktrace.sh: support old bash version

Old bash version don't support associative array variables. Avoid to use
associative array variables to avoid error.

Without this, old bash version will report error as fellowing
[ 15.954042] Kernel panic - not syncing: sysrq triggered crash
[ 15.955252] CPU: 1 PID: 167 Comm: sh Not tainted 5.18.0-rc1-00208-gb7d075db2fd5 #4
[ 15.956472] Hardware name: Hobot J5 Virtual development board (DT)
[ 15.957856] Call trace:
./scripts/decode_stacktrace.sh: line 128: ,dump_backtrace: syntax error: operand expected (error token is ",dump_backtrace")

Link: https://lkml.kernel.org/r/20220409180331.24047-1-schspa@gmail.com
Signed-off-by: Schspa Shi <schspa@gmail.com>
Cc: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

scripts/decode_stacktrace.sh: indicate 'auto' can be used for base path

Add "auto" to the usage message so that it's a little clearer that you can
pass "auto" as the second argument. When passing "auto" the script tries
to find the base path automatically instead of requiring it be passed on
the commandline. Also use [<variable>] to indicate the variable argument
and that it is optional so that we can differentiate from the literal
"auto" that should be passed.

Link: https://lkml.kernel.org/r/20210511003845.2429846-11-swboyd@chromium.org
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Evan Green <evgreen@chromium.org>
Cc: Hsin-Yi Wang <hsinyi@chromium.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/decode_stacktrace.sh: silence stderr messages from addr2line/nm

Sometimes if you're using tools that have linked things improperly or have
new features/sections that older tools don't expect you'll see warnings
printed to stderr. We don't really care about these warnings, so let's
just silence these messages to cleanup output of this script.

Link: https://lkml.kernel.org/r/20210511003845.2429846-10-swboyd@chromium.org
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Evan Green <evgreen@chromium.org>
Cc: Hsin-Yi Wang <hsinyi@chromium.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/decode_stacktrace.sh: support debuginfod

Now that stacktraces contain the build ID information we can update this
script to use debuginfod-find to locate the debuginfo for the vmlinux and
modules automatically. This can replace the existing code that requires
specifying a path to vmlinux or tries to find the vmlinux and modules
automatically by using the release number. Work it into the script as a
fallback option if the vmlinux isn't specified on the commandline.

Link: https://lkml.kernel.org/r/20210511003845.2429846-9-swboyd@chromium.org
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Evan Green <evgreen@chromium.org>
Cc: Hsin-Yi Wang <hsinyi@chromium.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/decode_stacktrace.sh: guess path to vmlinux by release name

Add option decode_stacktrace -r <release> to specify only release name.
This is enough to guess standard paths to vmlinux and modules:

$ echo -e 'schedule+0x0/0x0
tap_open+0x0/0x0 [tap]' |
./scripts/decode_stacktrace.sh -r 5.4.0-37-generic
schedule (kernel/sched/core.c:4138)
tap_open (drivers/net/tap.c:502) tap

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Sasha Levin <sashal@kernel.org>
Link: http://lkml.kernel.org/r/159282923334.248444.2399153100007347838.stgit@buzz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/decode_stacktrace.sh: guess path to modules

Try to find module in directory with vmlinux (for fresh build). Then try
standard paths where debuginfo are usually placed. Pick first file which
have elf section '.debug_line'.

Before:

$ echo 'tap_open+0x0/0x0 [tap]' |
./scripts/decode_stacktrace.sh /usr/lib/debug/boot/vmlinux-5.4.0-37-generic
WARNING! Modules path isn't set, but is needed to parse this symbol
tap_open+0x0/0x0 tap

After:

$ echo 'tap_open+0x0/0x0 [tap]' |
./scripts/decode_stacktrace.sh /usr/lib/debug/boot/vmlinux-5.4.0-37-generic
tap_open (drivers/net/tap.c:502) tap

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Sasha Levin <sashal@kernel.org>
Link: http://lkml.kernel.org/r/159282923068.248444.5461337458421616083.stgit@buzz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/decode_stacktrace.sh: guess basepath if not specified

Guess path to kernel sources using known location of symbol "kernel_init".
Make basepath argument optional.

Before:

$ echo 'vfs_open+0x0/0x0' | ./scripts/decode_stacktrace.sh vmlinux ""
vfs_open (home/khlebnikov/src/linux/fs/open.c:912)

After:

$ echo 'vfs_open+0x0/0x0' | ./scripts/decode_stacktrace.sh vmlinux
vfs_open (fs/open.c:912)

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Sasha Levin <sashal@kernel.org>
Link: http://lkml.kernel.org/r/159282922803.248444.2379229451667913634.stgit@buzz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/decode_stacktrace.sh: skip missing symbols

For now script turns missing symbols into '0' and make bogus decode. Skip
them instead. Also simplify parsing output of 'nm'.

Before:

$ echo 'xxx+0x0/0x0' | ./scripts/decode_stacktrace.sh vmlinux ""
xxx (home/khlebnikov/src/linux/./arch/x86/include/asm/processor.h:398)

After:

$ echo 'xxx+0x0/0x0' | ./scripts/decode_stacktrace.sh vmlinux ""
xxx+0x0/0x0

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Sasha Levin <sashal@kernel.org>
Link: http://lkml.kernel.org/r/159282922499.248444.4883465570858385250.stgit@buzz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/decode_stacktrace: strip basepath from all paths

Currently the basepath is removed only from the beginning of the string.
When the symbol is inlined and there's multiple line outputs of
addr2line, only the first line would have basepath removed.

Change to remove the basepath prefix from all lines.

Fixes: 31013836a71e ("scripts/decode_stacktrace: match basepath using shell prefix operator, not regex")
Co-developed-by: Shik Chen <shik@chromium.org>
Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
Signed-off-by: Shik Chen <shik@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Nicolas Boichat <drinkcat@chromium.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Link: http://lkml.kernel.org/r/20200720082709.252805-1-pihsun@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/decode_stacktrace: warn when modpath is needed but is unset

When a user tries to parse a symbol located inside a module he must have
modpath set. Otherwise, decode_stacktrace won't be able to parse the
symbol correctly.

Right now the failure is silent and easily missed by the user. What's
worse is that by the time the user realizes what happened (or someone on
LKML asks him to add the modpath and re-run), he might have already got
rid of the vmlinux/modules.

Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/decode_stacktrace: Accept dash/underscore in modules

The manpage for modprobe mentions that dashes and underscores are
treated interchangeably in module names. The stack trace dumps seem to
print module names with underscores. Use bash to replace _ with the
pattern [-_] so that file names with dashes or underscores can be found.

For example, this line:
[ 27.919759] hda_widget_sysfs_init+0x2b8/0x3a5 [snd_hda_core]

should find a module named snd-hda-core.ko.

Link: http://lkml.kernel.org/r/20190531205926.42474-1-evgreen@chromium.org
Signed-off-by: Evan Green <evgreen@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Evan Green <evgreen@chromium.org>
Cc: Nicolas Boichat <drinkcat@chromium.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Manuel Traut <manut@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/decode_stacktrace: look for modules with .ko.debug extension

In Chromium OS kernel builds, we split the debug information as .ko.debug
files, and that's what decode_stacktrace.sh needs to use.

Relax objfile matching rule to allow any .ko* file to be matched.

[drinkcat@chromium.org: add quotes around name pattern]
Link: http://lkml.kernel.org/r/20190528103346.42720-1-drinkcat@chromium.org
Link: http://lkml.kernel.org/r/20190521234148.64060-1-drinkcat@chromium.org
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/decode_stacktrace: match basepath using shell prefix operator, not regex

The basepath may contain special characters, which would confuse the regex
matcher. ${var#prefix} does the right thing.

Link: http://lkml.kernel.org/r/20190518055946.181563-1-drinkcat@chromium.org
Fixes: 67a28de47faa8358 ("scripts/decode_stacktrace: only strip base path when a prefix of the path")
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/decode_stacktrace.sh: prefix addr2line with $CROSS_COMPILE

At least for ARM64 kernels compiled with the crosstoolchain from
Debian/stretch or with the toolchain from kernel.org the line number is
not decoded correctly by 'decode_stacktrace.sh':

$ echo "[ 136.513051] f1+0x0/0xc [kcrash]" | \
CROSS_COMPILE=/opt/gcc-8.1.0-nolibc/aarch64-linux/bin/aarch64-linux- \
./scripts/decode_stacktrace.sh /scratch/linux-arm64/vmlinux \
/scratch/linux-arm64 \
/nfs/debian/lib/modules/4.20.0-devel
[ 136.513051] f1 (/linux/drivers/staging/kcrash/kcrash.c:68) kcrash

If addr2line from the toolchain is used the decoded line number is correct:

[ 136.513051] f1 (/linux/drivers/staging/kcrash/kcrash.c:57) kcrash

Link: http://lkml.kernel.org/r/20190527083425.3763-1-manut@linutronix.de
Signed-off-by: Manuel Traut <manut@linutronix.de>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/decode_stacktrace.sh: handle RIP address with segment

decode line:

RIP: 0010:khugepaged+0x2a2/0x2280

into

RIP: 0010:khugepaged (mm/khugepaged.c:1885)

Link: http://lkml.kernel.org/r/154660071227.52726.15645307951282727605.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/decode_stacktrace: only strip base path when a prefix of the path

Running something like:

decodecode vmlinux .

leads to interested results where not only the leading "." gets stripped
from the displayed paths, but also anywhere in the string, displaying
something like:

kvm_vcpu_check_block (arch/arm64/kvm/virt/kvm/kvm_mainc:2141)

which doesn't help further processing.

Fix it by only stripping the base path if it is a prefix of the path.

Link: http://lkml.kernel.org/r/20181210174659.31054-3-marc.zyngier@arm.com
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

scripts/decode_stacktrace.sh: Fix address line detection on x86

Kirill reported that the decode_stacktrace.sh script was broken by the
following commit:

bb5e5ce545f2 ("x86/dumpstack: Remove kernel text addresses from stack dump")

Fix it by updating the per-line absolute address check to also check for
function-based address lines like the following:

write_sysrq_trigger+0x51/0x60

I didn't remove the check for absolute addresses because it's still
needed for ARM.

Reported-by: Kirill A. Shutemov <kirill@shutemov.name>
Tested-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <alexander.levin@verizon.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: bb5e5ce545f2 ("x86/dumpstack: Remove kernel text addresses from stack dump")
Link: http://lkml.kernel.org/r/20161128230635.4n2ofgawltgexgcg@treble
Signed-off-by: Ingo Molnar <mingo@kernel.org>

scripts/decode_stacktrace.sh: handle symbols in modules

scripts/decode_stacktrace.sh presently displays module symbols as

func+0x0ff/0x5153 [module]

Add a third argument: the pathname of a directory where the script
should look for the file module.ko so that the output appears as

func (foo/bar.c:123) module

Without the argument or if the module file isn't found the script prints
such symbols as is without decoding.

Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts: decode_stacktrace: fix ARM architecture decoding

Fix the stack decoder for the ARM architecture.
An ARM stack is designed as :

[ 81.547704] [<c023eb04>] (bucket_find_contain) from [<c023ec88>] (check_sync+0x40/0x4f8)
[ 81.559668] [<c023ec88>] (check_sync) from [<c023f8c4>] (debug_dma_sync_sg_for_cpu+0x128/0x194)
[ 81.571583] [<c023f8c4>] (debug_dma_sync_sg_for_cpu) from [<c0327dec>] (__videobuf_s

The current script doesn't expect the symbols to be bound by
parenthesis, and triggers the following errors :

awk: cmd. line:1: error: Unmatched ( or \(: / (check_sync$/
[ 81.547704] (bucket_find_contain) from (check_sync+0x40/0x4f8)

Fix it by chopping starting and ending parenthesis from the each symbol
name.

As a side note, this probably comes from the function
dump_backtrace_entry(), which is implemented differently for each
architecture. That makes a single decoding script a bit a challenge.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

decode_stacktrace: make stack dump output useful again

Right now when people try to report issues in the kernel they send stack
dumps to eachother, which looks something like this:

[ 6.906437] [<ffffffff811f0e90>] ? backtrace_test_irq_callback+0x20/0x20
[ 6.907121] [<ffffffff84388ce8>] dump_stack+0x52/0x7f
[ 6.907640] [<ffffffff811f0ec8>] backtrace_regression_test+0x38/0x110
[ 6.908281] [<ffffffff813596a0>] ? proc_create_data+0xa0/0xd0
[ 6.908870] [<ffffffff870a8040>] ? proc_modules_init+0x22/0x22
[ 6.909480] [<ffffffff810020c2>] do_one_initcall+0xc2/0x1e0
[...]

However, most of the text you get is pure garbage.

The only useful thing above is the function name. Due to the amount of
different kernel code versions and various configurations being used,
the kernel address and the offset into the function are not really
helpful in determining where the problem actually occured.

Too often the result of someone looking at a stack dump is asking the
person who sent it for a translation for one or more 'addr2line'
translations. Which slows down the entire process of debugging the
issue (and really annoying).

The decode_stacktrace script is an attempt to make the output more
useful and easy to work with by translating all kernel addresses in the
stack dump into line numbers. Which means that the stack dump would
look like this:

[ 635.148361] dump_stack (lib/dump_stack.c:52)
[ 635.149127] warn_slowpath_common (kernel/panic.c:418)
[ 635.150214] warn_slowpath_null (kernel/panic.c:453)
[ 635.151031] _oalloc_pages_slowpath+0x6a/0x7d0
[ 635.152171] ? zone_watermark_ok (mm/page_alloc.c:1728)
[ 635.152988] ? get_page_from_freelist (mm/page_alloc.c:1939)
[ 635.154766] __alloc_pages_nodemask (mm/page_alloc.c:2766)

It's pretty obvious why this is better than the previous stack dump
before.

Usage is pretty simple:

./decode_stacktrace.sh [vmlinux] [base path]

Where vmlinux is the vmlinux to extract line numbers from and base path
is the path that points to the root of the build tree, for example:

./decode_stacktrace.sh vmlinux /home/sasha/linux/ < input.log > output.log

The stack trace should be piped through it (I, for example, just pipe
the output of the serial console of my KVM test box through it).

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>