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14b6320953
7 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Howard Chu
|
7a2fb5619c |
perf trace: Fix iteration of syscall ids in syscalltbl->entries
This is a bug found when implementing pretty-printing for the
landlock_add_rule system call, I decided to send this patch separately
because this is a serious bug that should be fixed fast.
I wrote a test program to do landlock_add_rule syscall in a loop,
yet perf trace -e landlock_add_rule freezes, giving no output.
This bug is introduced by the false understanding of the variable "key"
below:
```
for (key = 0; key < trace->sctbl->syscalls.nr_entries; ++key) {
struct syscall *sc = trace__syscall_info(trace, NULL, key);
...
}
```
The code above seems right at the beginning, but when looking at
syscalltbl.c, I found these lines:
```
for (i = 0; i <= syscalltbl_native_max_id; ++i)
if (syscalltbl_native[i])
++nr_entries;
entries = tbl->syscalls.entries = malloc(sizeof(struct syscall) * nr_entries);
...
for (i = 0, j = 0; i <= syscalltbl_native_max_id; ++i) {
if (syscalltbl_native[i]) {
entries[j].name = syscalltbl_native[i];
entries[j].id = i;
++j;
}
}
```
meaning the key is merely an index to traverse the syscall table,
instead of the actual syscall id for this particular syscall.
So if one uses key to do trace__syscall_info(trace, NULL, key), because
key only goes up to trace->sctbl->syscalls.nr_entries, for example, on
my X86_64 machine, this number is 373, it will end up neglecting all
the rest of the syscall, in my case, everything after `rseq`, because
the traversal will stop at 373, and `rseq` is the last syscall whose id
is lower than 373
in tools/perf/arch/x86/include/generated/asm/syscalls_64.c:
```
...
[334] = "rseq",
[424] = "pidfd_send_signal",
...
```
The reason why the key is scrambled but perf trace works well is that
key is used in trace__syscall_info(trace, NULL, key) to do
trace->syscalls.table[id], this makes sure that the struct syscall returned
actually has an id the same value as key, making the later bpf_prog
matching all correct.
After fixing this bug, I can do perf trace on 38 more syscalls, and
because more syscalls are visible, we get 8 more syscalls that can be
augmented.
before:
perf $ perf trace -vv --max-events=1 |& grep Reusing
Reusing "open" BPF sys_enter augmenter for "stat"
Reusing "open" BPF sys_enter augmenter for "lstat"
Reusing "open" BPF sys_enter augmenter for "access"
Reusing "connect" BPF sys_enter augmenter for "accept"
Reusing "sendto" BPF sys_enter augmenter for "recvfrom"
Reusing "connect" BPF sys_enter augmenter for "bind"
Reusing "connect" BPF sys_enter augmenter for "getsockname"
Reusing "connect" BPF sys_enter augmenter for "getpeername"
Reusing "open" BPF sys_enter augmenter for "execve"
Reusing "open" BPF sys_enter augmenter for "truncate"
Reusing "open" BPF sys_enter augmenter for "chdir"
Reusing "open" BPF sys_enter augmenter for "mkdir"
Reusing "open" BPF sys_enter augmenter for "rmdir"
Reusing "open" BPF sys_enter augmenter for "creat"
Reusing "open" BPF sys_enter augmenter for "link"
Reusing "open" BPF sys_enter augmenter for "unlink"
Reusing "open" BPF sys_enter augmenter for "symlink"
Reusing "open" BPF sys_enter augmenter for "readlink"
Reusing "open" BPF sys_enter augmenter for "chmod"
Reusing "open" BPF sys_enter augmenter for "chown"
Reusing "open" BPF sys_enter augmenter for "lchown"
Reusing "open" BPF sys_enter augmenter for "mknod"
Reusing "open" BPF sys_enter augmenter for "statfs"
Reusing "open" BPF sys_enter augmenter for "pivot_root"
Reusing "open" BPF sys_enter augmenter for "chroot"
Reusing "open" BPF sys_enter augmenter for "acct"
Reusing "open" BPF sys_enter augmenter for "swapon"
Reusing "open" BPF sys_enter augmenter for "swapoff"
Reusing "open" BPF sys_enter augmenter for "delete_module"
Reusing "open" BPF sys_enter augmenter for "setxattr"
Reusing "open" BPF sys_enter augmenter for "lsetxattr"
Reusing "openat" BPF sys_enter augmenter for "fsetxattr"
Reusing "open" BPF sys_enter augmenter for "getxattr"
Reusing "open" BPF sys_enter augmenter for "lgetxattr"
Reusing "openat" BPF sys_enter augmenter for "fgetxattr"
Reusing "open" BPF sys_enter augmenter for "listxattr"
Reusing "open" BPF sys_enter augmenter for "llistxattr"
Reusing "open" BPF sys_enter augmenter for "removexattr"
Reusing "open" BPF sys_enter augmenter for "lremovexattr"
Reusing "fsetxattr" BPF sys_enter augmenter for "fremovexattr"
Reusing "open" BPF sys_enter augmenter for "mq_open"
Reusing "open" BPF sys_enter augmenter for "mq_unlink"
Reusing "fsetxattr" BPF sys_enter augmenter for "add_key"
Reusing "fremovexattr" BPF sys_enter augmenter for "request_key"
Reusing "fremovexattr" BPF sys_enter augmenter for "inotify_add_watch"
Reusing "fremovexattr" BPF sys_enter augmenter for "mkdirat"
Reusing "fremovexattr" BPF sys_enter augmenter for "mknodat"
Reusing "fremovexattr" BPF sys_enter augmenter for "fchownat"
Reusing "fremovexattr" BPF sys_enter augmenter for "futimesat"
Reusing "fremovexattr" BPF sys_enter augmenter for "newfstatat"
Reusing "fremovexattr" BPF sys_enter augmenter for "unlinkat"
Reusing "fremovexattr" BPF sys_enter augmenter for "linkat"
Reusing "open" BPF sys_enter augmenter for "symlinkat"
Reusing "fremovexattr" BPF sys_enter augmenter for "readlinkat"
Reusing "fremovexattr" BPF sys_enter augmenter for "fchmodat"
Reusing "fremovexattr" BPF sys_enter augmenter for "faccessat"
Reusing "fremovexattr" BPF sys_enter augmenter for "utimensat"
Reusing "connect" BPF sys_enter augmenter for "accept4"
Reusing "fremovexattr" BPF sys_enter augmenter for "name_to_handle_at"
Reusing "fremovexattr" BPF sys_enter augmenter for "renameat2"
Reusing "open" BPF sys_enter augmenter for "memfd_create"
Reusing "fremovexattr" BPF sys_enter augmenter for "execveat"
Reusing "fremovexattr" BPF sys_enter augmenter for "statx"
after
perf $ perf trace -vv --max-events=1 |& grep Reusing
Reusing "open" BPF sys_enter augmenter for "stat"
Reusing "open" BPF sys_enter augmenter for "lstat"
Reusing "open" BPF sys_enter augmenter for "access"
Reusing "connect" BPF sys_enter augmenter for "accept"
Reusing "sendto" BPF sys_enter augmenter for "recvfrom"
Reusing "connect" BPF sys_enter augmenter for "bind"
Reusing "connect" BPF sys_enter augmenter for "getsockname"
Reusing "connect" BPF sys_enter augmenter for "getpeername"
Reusing "open" BPF sys_enter augmenter for "execve"
Reusing "open" BPF sys_enter augmenter for "truncate"
Reusing "open" BPF sys_enter augmenter for "chdir"
Reusing "open" BPF sys_enter augmenter for "mkdir"
Reusing "open" BPF sys_enter augmenter for "rmdir"
Reusing "open" BPF sys_enter augmenter for "creat"
Reusing "open" BPF sys_enter augmenter for "link"
Reusing "open" BPF sys_enter augmenter for "unlink"
Reusing "open" BPF sys_enter augmenter for "symlink"
Reusing "open" BPF sys_enter augmenter for "readlink"
Reusing "open" BPF sys_enter augmenter for "chmod"
Reusing "open" BPF sys_enter augmenter for "chown"
Reusing "open" BPF sys_enter augmenter for "lchown"
Reusing "open" BPF sys_enter augmenter for "mknod"
Reusing "open" BPF sys_enter augmenter for "statfs"
Reusing "open" BPF sys_enter augmenter for "pivot_root"
Reusing "open" BPF sys_enter augmenter for "chroot"
Reusing "open" BPF sys_enter augmenter for "acct"
Reusing "open" BPF sys_enter augmenter for "swapon"
Reusing "open" BPF sys_enter augmenter for "swapoff"
Reusing "open" BPF sys_enter augmenter for "delete_module"
Reusing "open" BPF sys_enter augmenter for "setxattr"
Reusing "open" BPF sys_enter augmenter for "lsetxattr"
Reusing "openat" BPF sys_enter augmenter for "fsetxattr"
Reusing "open" BPF sys_enter augmenter for "getxattr"
Reusing "open" BPF sys_enter augmenter for "lgetxattr"
Reusing "openat" BPF sys_enter augmenter for "fgetxattr"
Reusing "open" BPF sys_enter augmenter for "listxattr"
Reusing "open" BPF sys_enter augmenter for "llistxattr"
Reusing "open" BPF sys_enter augmenter for "removexattr"
Reusing "open" BPF sys_enter augmenter for "lremovexattr"
Reusing "fsetxattr" BPF sys_enter augmenter for "fremovexattr"
Reusing "open" BPF sys_enter augmenter for "mq_open"
Reusing "open" BPF sys_enter augmenter for "mq_unlink"
Reusing "fsetxattr" BPF sys_enter augmenter for "add_key"
Reusing "fremovexattr" BPF sys_enter augmenter for "request_key"
Reusing "fremovexattr" BPF sys_enter augmenter for "inotify_add_watch"
Reusing "fremovexattr" BPF sys_enter augmenter for "mkdirat"
Reusing "fremovexattr" BPF sys_enter augmenter for "mknodat"
Reusing "fremovexattr" BPF sys_enter augmenter for "fchownat"
Reusing "fremovexattr" BPF sys_enter augmenter for "futimesat"
Reusing "fremovexattr" BPF sys_enter augmenter for "newfstatat"
Reusing "fremovexattr" BPF sys_enter augmenter for "unlinkat"
Reusing "fremovexattr" BPF sys_enter augmenter for "linkat"
Reusing "open" BPF sys_enter augmenter for "symlinkat"
Reusing "fremovexattr" BPF sys_enter augmenter for "readlinkat"
Reusing "fremovexattr" BPF sys_enter augmenter for "fchmodat"
Reusing "fremovexattr" BPF sys_enter augmenter for "faccessat"
Reusing "fremovexattr" BPF sys_enter augmenter for "utimensat"
Reusing "connect" BPF sys_enter augmenter for "accept4"
Reusing "fremovexattr" BPF sys_enter augmenter for "name_to_handle_at"
Reusing "fremovexattr" BPF sys_enter augmenter for "renameat2"
Reusing "open" BPF sys_enter augmenter for "memfd_create"
Reusing "fremovexattr" BPF sys_enter augmenter for "execveat"
Reusing "fremovexattr" BPF sys_enter augmenter for "statx"
TL;DR:
These are the new syscalls that can be augmented
Reusing "openat" BPF sys_enter augmenter for "open_tree"
Reusing "openat" BPF sys_enter augmenter for "openat2"
Reusing "openat" BPF sys_enter augmenter for "mount_setattr"
Reusing "openat" BPF sys_enter augmenter for "move_mount"
Reusing "open" BPF sys_enter augmenter for "fsopen"
Reusing "openat" BPF sys_enter augmenter for "fspick"
Reusing "openat" BPF sys_enter augmenter for "faccessat2"
Reusing "openat" BPF sys_enter augmenter for "fchmodat2"
as for the perf trace output:
before
perf $ perf trace -e faccessat2 --max-events=1
[no output]
after
perf $ ./perf trace -e faccessat2 --max-events=1
0.000 ( 0.037 ms): waybar/958 faccessat2(dfd: 40, filename: "uevent") = 0
P.S. The reason why this bug was not found in the past five years is
probably because it only happens to the newer syscalls whose id is
greater, for instance, faccessat2 of id 439, which not a lot of people
care about when using perf trace.
[Arnaldo]: notes
That and the fact that the BPF code was hidden before having to use -e,
that got changed kinda recently when we switched to using BPF skels for
augmenting syscalls in 'perf trace':
⬢[acme@toolbox perf-tools-next]$ git log --oneline tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c
|
||
Arnaldo Carvalho de Melo
|
db6b8cc891 |
perf trace: Remove union from syscalltbl, all the fields are needed
When we moved to a syscalltbl generated from the kernel syscall tables (arch/..../syscall*.tbl) the idea was to either use it, when having the generator (e.g. tools/perf/arch/x86/entry/syscalls/syscalltbl.sh), or falling back to the previous audit-libs based way of mapping syscall ids to strings and the other way around. At first we just needed the audit_detect_machine() return to then use it to the str->id/id->str, or the other fields for the now used by default in the most well developed arches method of using the syscall table generator. The problem is that then the libaudit code fell into disrepair, and architectures where it is the method used are not working. Now, with NO_SYSCALL_TABLE=1 being possible to pass on the make command line we can automate the testing of that method even on x86-64, arm64, etc. And doing it I noted that we actually use fields in both entries in the union, oops, so ditch the union, as we need all those fields at the same time. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
||
|
Arnaldo Carvalho de Melo
|
30a910d7d3 |
perf trace: Preallocate the syscall table
We'll continue reading its details from tracefs as we need it, but preallocate the whole thing otherwise we may realloc and end up with pointers to the previous buffer. I.e. in an upcoming algorithm we'll look for syscalls that have function signatures that are similar to a given syscall to see if we can reuse its BPF augmenter, so we may be at syscall 42, having a 'struct syscall' pointing to that slot in trace->syscalls.table[] and try to read the slot for an yet unread syscall, which would realloc that table to read the info for syscall 43, say, which would trigger a realoc of trace->syscalls.table[], and then the pointer we had for syscall 42 would be pointing to the previous block of memory. b00m. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Link: https://lkml.kernel.org/n/tip-m3cjzzifibs13imafhkk77a0@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
||
Greg Kroah-Hartman
|
b24413180f |
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> |
||
|
Arnaldo Carvalho de Melo
|
89be3f8ab7 |
perf syscalltbl: Support glob matching on syscall names
With two new methods, one to find the first match, returning its syscall id and its index in whatever internal database it keeps the syscall into, then one to find the next match, if any. Implemented only on arches where we actually read the syscall table from the kernel sources, i.e. x86-64 for now, all the others use the libaudit method for which this returns -1, i.e. just stubs were added, with the actual implementation using whatever libaudit functions for matching that may be available. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/n/tip-i0sj4rxk1a63pfe9gl8z8irs@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
||
|
Arnaldo Carvalho de Melo
|
5af56fab2b |
perf tools: Allow generating per-arch syscall table arrays
Tools should use a mechanism similar to arch/x86/entry/syscalls/ to
generate a header file with the definitions for two variables:
static const char *syscalltbl_x86_64[] = {
[0] = "read",
[1] = "write",
<SNIP>
[324] = "membarrier",
[325] = "mlock2",
[326] = "copy_file_range",
};
static const int syscalltbl_x86_64_max_id = 326;
In a per arch file that should then be included in
tools/perf/util/syscalltbl.c.
First one will be for x86_64.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-02uuamkxgccczdth8komspgp@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Arnaldo Carvalho de Melo
|
fd0db10268 |
perf trace: Move syscall table id <-> name routines to separate class
We're using libaudit for doing name to id and id to syscall name translations, but that makes 'perf trace' to have to wait for newer libaudit versions supporting recently added syscalls, such as "userfaultfd" at the time of this changeset. We have all the information right there, in the kernel sources, so move this code to a separate place, wrapped behind functions that will progressively use the kernel source files to extract the syscall table for use in 'perf trace'. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/n/tip-i38opd09ow25mmyrvfwnbvkj@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |