The size of dirent->dt_name is NAME_MAX + 1, but the size for the 'path'
buffer is hard coded at 256, which may truncate it because we also
prepend "/proc/", so that all that into account and thank gcc 7 for this
warning:
/git/linux/tools/perf/util/thread_map.c: In function 'thread_map__new_by_uid':
/git/linux/tools/perf/util/thread_map.c:119:39: error: '%s' directive output may be truncated writing up to 255 bytes into a region of size 250 [-Werror=format-truncation=]
snprintf(path, sizeof(path), "/proc/%s", dirent->d_name);
^~
In file included from /usr/include/stdio.h:939:0,
from /git/linux/tools/perf/util/thread_map.c:5:
/usr/include/bits/stdio2.h:64:10: note: '__builtin___snprintf_chk' output between 7 and 262 bytes into a destination of size 256
return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
__bos (__s), __fmt, __va_arg_pack ());
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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-csy0r8zrvz5efccgd4k12c82@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The readdir() function is thread safe as long as just one thread uses a
DIR, which is the case in thread_map, so, to avoid breaking the build
with glibc-2.23.90 (upcoming 2.24), use it instead of readdir_r().
See: http://man7.org/linux/man-pages/man3/readdir.3.html
"However, in modern implementations (including the glibc implementation),
concurrent calls to readdir() that specify different directory streams
are thread-safe. In cases where multiple threads must read from the
same directory stream, using readdir() with external synchronization is
still preferable to the use of the deprecated readdir_r(3) function."
Noticed while building on a Fedora Rawhide docker container.
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-del8h2a0f40z75j4r42l96l0@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:
New features:
- Allow filtering out of perf's PID via 'perf record --exclude-perf'. (Wang Nan)
- 'perf trace' now supports syscall groups, like strace, i.e:
$ trace -e file touch file
Will expand 'file' into multiple, file related, syscalls. More work needed to
add extra groups for other syscall groups, and also to complement what was
added for the 'file' group, included as a proof of concept. (Arnaldo Carvalho de Melo)
- Add lock_pi stresser to 'perf bench futex', to test the kernel code
related to FUTEX_(UN)LOCK_PI. (Davidlohr Bueso)
User visible fixes:
- Apply --filter to all events in a glob matching, not just the last one. (Wang Nan)
Documentation changes:
- Document setting '-e pmu/period=N/' in the 'perf record' man page. (Kan Liang)
Infrastructure changes:
- 'perf probe' code simplifications and movements to separate files. (Masami Hiramatsu)
- Fix makefile generation under 'dash'. (Sergei Trofimovich)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When we started adding extra stuff per array entry, growing the size of
those entries to more than sizeof(pid_t), we had to convert those sizeof
operations to the more robust sizeof(map->map[0]) idiom, that is future
proof, i.e. if/when we add more stuff to those entries, that expression
will produce the new per-entry size.
And besides that, we need to zero out those extra fields, that sometimes
may not get filled, like when we couldn't care less about the comms,
since we don't need those, but since we will try freeing it at
thread_map__delete(), we better fix it.
That is why a thread_map__realloc() was provided.
But that method wasn't used in thread_map__new_by_uid(), fix it.
Reported-by: Ingo Molnar <mingo@kernel.org>
Fixes: 792402fd5c ("perf thrad_map: Add comm string into array")
Fixes: 9d7e8c3a96 ("perf tools: Add thread_map__(alloc|realloc) helpers")
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-6a0swlm6m8lnu3wpjv284hkb@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The following commit:
b52956c perf tools: Allow multiple threads or processes in record, stat, top
introduced a bug in the thread_map code which caused perf record -a to
not setup system-wide monitoring properly.
$ taskset -c 1 noploop 1000 &
$ perf record -a -C 1 sleep 10
$ perf report -D | tail -20
cycles stats:
TOTAL events: 4413
MMAP events: 4025
COMM events: 340
SAMPLE events: 48
Here I was expecting about 10,000 samples and not 48.
In system-wide mode, the PID passed to perf_event_open() must be -1 and
it was 0. That caused the kernel to setup a per-process event on PID:0.
Consequently, the number of samples captured does not correspond to the
requested measurement.
The following one-liner fixes the problem for me with or without -C.
I would also suggest to change the malloc() to something that matches
the struct definition. thread_map->map[] is declared as int map[] and
not pid_t map[]. If map[] can only contain pids, then change the struct
definition.
Acked-by: David Ahern <dsahern@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120221145424.GA6757@quad
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To untangle it from struct thread handling, that is tied to symbols, etc.
Right now in the python bindings I'm working on I need just a subset of
the util/ files, untangling it allows me to do that.
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
