kernel/tools/perf/util/cgroup.c, branch linux-4.15.y

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

2017-11-02T10:10:55Z

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 Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

perf cgroup: Fix refcount usage

2017-07-25T14:23:50Z

When converting from atomic_t to refcount_t we didn't follow the usual step of initializing it to one before taking any new reference, which trips over checking if taking a reference for a freed refcount_t, fix it. Brendan's report: --- It's 4.12-rc7, with node v4.4.1. I'm building 4.13-rc1 now, as I hit what I think is another unrelated perf bug and I'm starting to wonder what else is broken on that version: (root) /mnt/src/linux-4.12-rc7/tools/perf # ./perf record -F 99 -a -e cpu-clock --cgroup=docker/f9e9d5df065b14646e8a11edc837a13877fd90c171137b2ba3feb67a0201cb65 -g perf: /mnt/src/linux-4.12-rc7/tools/include/linux/refcount.h:108: refcount_inc: Assertion `!(!refcount_inc_not_zero(r))' failed. Aborted that used to work... --- Testing it: Before: # perf stat -e cycles -C 0 --cgroup / perf: /home/acme/git/linux/tools/include/linux/refcount.h:108: refcount_inc: Assertion `!(!refcount_inc_not_zero(r))' failed. Aborted (core dumped) # After: # perf stat -e cycles -C 0 --cgroup / ^C Performance counter stats for 'CPU(s) 0': 132,081,393 cycles / 2.492942763 seconds time elapsed # Reported-by: Brendan Gregg Acked-by: Elena Reshetova Cc: Alexander Shishkin Cc: David Ahern Cc: David Carrillo-Cisneros Cc: Kees Kook Cc: Krister Johansen Cc: Paul Turner Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Sudeep Holla Cc: Thomas-Mich Richter Cc: Wang Nan Fixes: 79c5fe6db8c7 ("perf cgroup: Convert cgroup_sel.refcnt from atomic_t to refcount_t") Link: http://lkml.kernel.org/n/tip-l7ovfblq14ip2i08m1g0fkhv@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Replace STR() calls with __stringify()

2017-04-19T16:01:47Z

Both do the same thing, the later is the one we get from linux/stringify.h, i.e. we now use the same function name/practice as the kernel sources. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-w2sxa5o4bfx7fjrd5mu4zmke@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf cgroup: Convert cgroup_sel.refcnt from atomic_t to refcount_t

2017-03-03T22:07:14Z

The refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova Signed-off-by: David Windsor Signed-off-by: Hans Liljestrand Signed-off-by: Kees Kook Tested-by: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: alsa-devel@alsa-project.org Cc: Andrew Morton Cc: David Windsor Cc: Greg Kroah-Hartman Cc: Hans Liljestrand Cc: Jiri Olsa Cc: Kees Kook Cc: Mark Rutland Cc: Matija Glavinic Pecotic Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1487691303-31858-2-git-send-email-elena.reshetova@intel.com Signed-off-by: Arnaldo Carvalho de Melo

cgroup, perf_event: make perf_event controller work on cgroup2 hierarchy

2017-02-02T18:47:02Z

perf_event is a utility controller whose primary role is identifying cgroup membership to filter perf events; however, because it also tracks some per-css state, it can't be replaced by pure cgroup membership test. Mark the controller as implicitly enabled on the default hierarchy so that perf events can always be filtered based on cgroup v2 path as long as the controller is not mounted on a legacy hierarchy. "perf record" is updated accordingly so that it searches for both v1 and v2 hierarchies. A v1 hierarchy is used if perf_event is mounted on it; otherwise, it uses the v2 hierarchy. v2: Doc updated to reflect more flexible rebinding behavior. Signed-off-by: Tejun Heo Acked-by: Peter Zijlstra Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo

perf evlist: Rename for_each() macros to for_each_entry()

2016-06-23T14:26:15Z

To match the semantics for list.h in the kernel, that are used to implement those macros. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Milian Wolff Cc: Namhyung Kim Cc: Taeung Song Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-qbcjlgj0ffxquxscahbpddi3@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf subcmd: Create subcmd library

2015-12-17T17:27:14Z

Move the subcommand-related files from perf to a new library named libsubcmd.a. Since we're moving files anyway, go ahead and rename 'exec_cmd.*' to 'exec-cmd.*' to be consistent with the naming of all the other files. Signed-off-by: Josh Poimboeuf Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/c0a838d4c878ab17fee50998811612b2281355c1.1450193761.git.jpoimboe@redhat.com Signed-off-by: Arnaldo Carvalho de Melo

perf cgroup: Use atomic.h for refcounting

2015-05-15T19:12:20Z

Now that we have atomic.h, we should convert all of the existing refcounts to use it. Cc: Adrian Hunter Cc: Borislav Petkov Cc: David Ahern Cc: Don Zickus Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Namhyung Kim Cc: Stephane Eranian Link: http://lkml.kernel.org/n/tip-t3v2uma5digcj2tpkrs3m84u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf evlist: Introduce evlist__for_each() & friends

2014-01-13T13:06:25Z

For the common evsel list traversal, so that it becomes more compact. Use the opportunity to start ditching the 'perf_' from 'perf_evlist__', as discussed, as the whole conversion touches a lot of places, lets do it piecemeal when we have the chance due to other work, like in this case. Cc: Adrian Hunter Cc: David Ahern Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Mike Galbraith Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/n/tip-qnkx7dzm2h6m6uptkfk03ni6@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Use zfree to help detect use after free bugs

2013-12-27T20:08:19Z

Several areas already used this technique, so do some audit to consistently use it elsewhere. Cc: Adrian Hunter Cc: David Ahern Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Mike Galbraith Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/n/tip-9sbere0kkplwe45ak6rk4a1f@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo