talos-op-linux/tools/perf/jvmti, branch master

perf jvmti: Link against tools/lib/ctype.h to have weak strlcpy()

2019-10-15T14:47:38+00:00

The build of file libperf-jvmti.so succeeds but the resulting object fails to load: # ~/linux/tools/perf/perf record -k mono -- java \ -XX:+PreserveFramePointer \ -agentpath:/root/linux/tools/perf/libperf-jvmti.so \ hog 100000 123450 Error occurred during initialization of VM Could not find agent library /root/linux/tools/perf/libperf-jvmti.so in absolute path, with error: /root/linux/tools/perf/libperf-jvmti.so: undefined symbol: _ctype Add the missing _ctype symbol into the build script. Fixes: 79743bc927f6 ("perf jvmti: Link against tools/lib/string.o to have weak strlcpy()") Signed-off-by: Thomas Richter Cc: Heiko Carstens Cc: Vasily Gorbik Link: http://lore.kernel.org/lkml/20191008093841.59387-1-tmricht@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo

perf jvmti: Link against tools/lib/string.o to have weak strlcpy()

2019-09-20T12:18:45+00:00

That is needed in systems such some S/390 distros. $ readelf -s /tmp/build/perf/jvmti/jvmti-in.o | grep strlcpy 452: 0000000000002990 125 FUNC WEAK DEFAULT 119 strlcpy $ Thanks to Jiri Olsa for fixing up my initial stab at this, I forgot how Makefiles are picky about spaces versus tabs. Reported-by: Thomas Richter Cc: Adrian Hunter Cc: Andreas Krebbel Cc: Jiri Olsa Cc: Namhyung Kim Cc: Sergey Melnikov Link: https://lkml.kernel.org/n/tip-x8vg9sffgb2t1tzqmhkrulh7@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

tools build: Check if gettid() is available before providing helper

2019-06-17T18:57:19+00:00

Laura reported that the perf build failed in fedora when we got a glibc that provides gettid(), which I reproduced using fedora rawhide with the glibc-devel-2.29.9000-26.fc31.x86_64 package. Add a feature check to avoid providing a gettid() helper in such systems. On a fedora rawhide system with this patch applied we now get: [root@7a5f55352234 perf]# grep gettid /tmp/build/perf/FEATURE-DUMP feature-gettid=1 [root@7a5f55352234 perf]# cat /tmp/build/perf/feature/test-gettid.make.output [root@7a5f55352234 perf]# ldd /tmp/build/perf/feature/test-gettid.bin linux-vdso.so.1 (0x00007ffc6b1f6000) libc.so.6 => /lib64/libc.so.6 (0x00007f04e0a74000) /lib64/ld-linux-x86-64.so.2 (0x00007f04e0c47000) [root@7a5f55352234 perf]# nm /tmp/build/perf/feature/test-gettid.bin | grep -w gettid U gettid@@GLIBC_2.30 [root@7a5f55352234 perf]# While on a fedora:29 system: [acme@quaco perf]$ grep gettid /tmp/build/perf/FEATURE-DUMP feature-gettid=0 [acme@quaco perf]$ cat /tmp/build/perf/feature/test-gettid.make.output test-gettid.c: In function ‘main’: test-gettid.c:8:9: error: implicit declaration of function ‘gettid’; did you mean ‘getgid’? [-Werror=implicit-function-declaration] return gettid(); ^~~~~~ getgid cc1: all warnings being treated as errors [acme@quaco perf]$ Reported-by: Laura Abbott Tested-by: Laura Abbott Acked-by: Jiri Olsa Cc: Adrian Hunter Cc: Florian Weimer Cc: Namhyung Kim Cc: Stephane Eranian Link: https://lkml.kernel.org/n/tip-yfy3ch53agmklwu9o7rlgf9c@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf jvmti: Address gcc string overflow warning for strncpy()

2019-06-05T12:51:26+00:00

We are getting false positive gcc warning when we compile with gcc9 (9.1.1): CC jvmti/libjvmti.o In file included from /usr/include/string.h:494, from jvmti/libjvmti.c:5: In function ‘strncpy’, inlined from ‘copy_class_filename.constprop’ at jvmti/libjvmti.c:166:3: /usr/include/bits/string_fortified.h:106:10: error: ‘__builtin_strncpy’ specified bound depends on the length of the source argument [-Werror=stringop-overflow=] 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ jvmti/libjvmti.c: In function ‘copy_class_filename.constprop’: jvmti/libjvmti.c:165:26: note: length computed here 165 | size_t file_name_len = strlen(file_name); | ^~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors As per Arnaldo's suggestion use strlcpy(), which does the same thing and keeps gcc silent. Suggested-by: Arnaldo Carvalho de Melo Signed-off-by: Jiri Olsa Cc: Alexander Shishkin Cc: Ben Gainey Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/r/20190531131321.GB1281@krava Signed-off-by: Arnaldo Carvalho de Melo

perf jvmti: Separate jvmti cmlr check

2018-11-22T01:39:58+00:00

The Compiled Method Load Record (cmlr) is JDK specific interface to access JVM stack info. This makes the jvmti agent code not compile under another jdk, which does not support that. Separating jvmti cmlr check into special feature check, and adding HAVE_JVMTI_CMLR macro to indicate that. Mark cmlr code in jvmti/libjvmti.c with HAVE_JVMTI_CMLR, so we can compile it on system without cmlr support. This change makes the jvmti compile with java-1.8.0-ibm package. It's without the line numbers support, but the rest works. Adding NO_JVMTI_CMLR compile variable for testing. Signed-off-by: Jiri Olsa Cc: Alexander Shishkin Cc: Ben Gainey Cc: Gustavo Luiz Duarte Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/r/20181121154341.21521-1-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix undefined symbol scnprintf in libperf-jvmti.so

2018-11-05T19:28:00+00:00

Currently jvmti agent can not be used because function scnprintf is not present in the agent libperf-jvmti.so. As a result the JVM when using such agent to record JITed code profiling information will fail on looking up scnprintf: java: symbol lookup error: lib/libperf-jvmti.so: undefined symbol: scnprintf This commit fixes that by reverting to the use of snprintf, that can be looked up, instead of scnprintf, adding a proper check for the returned value in order to print a better error message when the jitdump file pathname is too long. Checking the returned value also helps to comply with some recent gcc versions, like gcc8, which will fail due to truncated writing checks related to the -Werror=format-truncation= flag. Signed-off-by: Gustavo Romero Acked-by: Jiri Olsa LPU-Reference: 1541117601-18937-2-git-send-email-gromero@linux.vnet.ibm.com Link: https://lkml.kernel.org/n/tip-mvpxxxy7wnzaj74cq75muw3f@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix compilation errors on gcc8

2018-07-11T13:39:57+00:00

We are getting following warnings on gcc8 that break compilation: $ make CC jvmti/jvmti_agent.o jvmti/jvmti_agent.c: In function ‘jvmti_open’: jvmti/jvmti_agent.c:252:35: error: ‘/jit-’ directive output may be truncated \ writing 5 bytes into a region of size between 1 and 4096 [-Werror=format-truncation=] snprintf(dump_path, PATH_MAX, "%s/jit-%i.dump", jit_path, getpid()); There's no point in checking the result of snprintf call in jvmti_open, the following open call will fail in case the name is mangled or too long. Using tools/lib/ function scnprintf that touches the return value from the snprintf() calls and thus get rid of those warnings. $ make DEBUG=1 CC arch/x86/util/perf_regs.o arch/x86/util/perf_regs.c: In function ‘arch_sdt_arg_parse_op’: arch/x86/util/perf_regs.c:229:4: error: ‘strncpy’ output truncated before terminating nul copying 2 bytes from a string of the same length [-Werror=stringop-truncation] strncpy(prefix, "+0", 2); ^~~~~~~~~~~~~~~~~~~~~~~~ Using scnprintf instead of the strncpy (which we know is safe in here) to get rid of that warning. Signed-off-by: Jiri Olsa Cc: Alexander Shishkin Cc: David Ahern Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20180702134202.17745-1-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf jvmti: Generate correct debug information for inlined code

2017-12-18T14:54:08+00:00

tools/perf/jvmti is broken in so far as it generates incorrect debug information. Specifically it attributes all debug lines to the original method being output even in the case that some code is being inlined from elsewhere. This patch fixes the issue. To test (from within linux/tools/perf): export JDIR=/usr/lib/jvm/java-8-openjdk-amd64/ make cat << __EOF > Test.java public class Test { private StringBuilder b = new StringBuilder(); private void loop(int i, String... args) { for (String a : args) b.append(a); long hc = b.hashCode() * System.nanoTime(); b = new StringBuilder(); b.append(hc); System.out.printf("Iteration %d = %d\n", i, hc); } public void run(String... args) { for (int i = 0; i < 10000; ++i) { loop(i, args); } } public static void main(String... args) { Test t = new Test(); t.run(args); } } __EOF $JDIR/bin/javac Test.java ./perf record -F 10000 -g -k mono $JDIR/bin/java -agentpath:`pwd`/libperf-jvmti.so Test ./perf inject --jit -i perf.data -o perf.data.jitted ./perf annotate -i perf.data.jitted --stdio | grep Test\.java: | sort -u Before this patch, Test.java line numbers get reported that are greater than the number of lines in the Test.java file. They come from the source file of the inlined function, e.g. java/lang/String.java:1085. For further validation one can examine those lines in the JDK source distribution and confirm that they map to inlined functions called by Test.java. After this patch, the filename of the inlined function is output rather than the incorrect original source filename. Signed-off-by: Ben Gainey Tested-by: Arnaldo Carvalho de Melo Tested-by: Stephane Eranian Cc: Alexander Shishkin Cc: Ben Gainey Cc: Colin King Cc: Darren Hart Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: 598b7c6919c7 ("perf jit: add source line info support") Link: http://lkml.kernel.org/r/20171122182541.d25599a3eb1ada3480d142fa@arm.com Signed-off-by: Kim Phillips Signed-off-by: Arnaldo Carvalho de Melo

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

2017-11-02T10:10:55+00:00

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 jit: fix typo: "incalid" -> "invalid"

2017-06-27T14:55:06+00:00

Trivial fix to typo in jvmti_close() warnx warning message. Signed-off-by: Colin King Cc: Alexander Shishkin Cc: Dan Carpenter Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/r/20170627124917.19151-1-colin.king@canonical.com Signed-off-by: Arnaldo Carvalho de Melo