perf ctf: Convert invalid chars in a string before set value
We observed some crazy apps on Android set their comm to unprintable
string. For example:
# cat /proc/10607/task/*/comm
tencent.qqmusic
...
Binder_2
日志输出线 <-- Chinese word 'log output thread'
WifiManager
...
'perf data convert' fails to convert perf.data with such string to CTF format.
For example:
# cat << EOF > ./badguy.c
#include <sys/prctl.h>
int main(int argc, char *argv[])
{
prctl(PR_SET_NAME, "\xe6\x97\xa5\xe5\xbf\x97\xe8\xbe\x93\xe5\x87\xba\xe7\xba\xbf");
while(1)
sleep(1);
return 0;
}
EOF
# gcc ./badguy.c
# perf record -e sched:* ./a.out
# perf data convert --to-ctf ./bad.ctf
CTF stream 4 flush failed
[ perf data convert: Converted 'perf.data' into CTF data './bad.ctf' ]
[ perf data convert: Converted and wrote 0.008 MB (78 samples) ]
# babeltrace ./bad.ctf/
[error] Packet size (18446744073709551615 bits) is larger than remaining file size (262144 bits).
[error] Stream index creation error.
[error] Open file stream error.
[warning] [Context] Cannot open_trace of format ctf at path ./bad.ctf.
[warning] [Context] cannot open trace "./bad.ctf" from ./bad.ctf/ for reading.
[error] Cannot open any trace for reading.
[error] opening trace "./bad.ctf/" for reading.
[error] none of the specified trace paths could be opened.
This patch converts unprintable characters to hexadecimal word.
After applying this patch the above test works correctly:
# ~/perf data convert --to-ctf ./good.ctf
[ perf data convert: Converted 'perf.data' into CTF data './good.ctf' ]
[ perf data convert: Converted and wrote 0.008 MB (78 samples) ]
# babeltrace ./good.ctf
..
[23:14:35.491665268] (+0.000001100) sched:sched_wakeup: { cpu_id = 4 }, { perf_ip = 0xFFFFFFFF810AEF33, perf_tid = 0, perf_pid = 0, perf_id = 5123, perf_period = 1, common_type = 270, common_flags = 45, common_preempt_count = 4, common_pid = 0, comm = "\xe6\x97\xa5\xe5\xbf\x97\xe8\xbe\x93\xe5\x87\xba\xe7\xba\xbf", pid = 1057, prio = 120, success = 1, target_cpu = 4 }
[23:14:35.491666230] (+0.000000962) sched:sched_wakeup: { cpu_id = 4 }, { perf_ip = 0xFFFFFFFF810AEF33, perf_tid = 0, perf_pid = 0, perf_id = 5122, perf_period = 1, common_type = 270, common_flags = 45, common_preempt_count = 4, common_pid = 0, comm = "\xe6\x97\xa5\xe5\xbf\x97\xe8\xbe\x93\xe5\x87\xba\xe7\xba\xbf", pid = 1057, prio = 120, success = 1, target_cpu = 4 }
..
Committer note:
To build perf with libabeltrace, use:
$ mkdir -p /tmp/build/perf
$ make LIBBABELTRACE=1 LIBBABELTRACE_DIR=/usr/local O=/tmp/build/perf -C tools/perf install-bin
Or equivalent (no O=, fixup LIBBABELTRACE_DIR, etc).
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1464348951-179595-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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