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tracing: handle broken names in ftrace filter

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If one filter item (for set_ftrace_filter and set_ftrace_notrace) is being
setup by more than 1 consecutive writes (FTRACE_ITER_CONT flag), it won't
be handled corretly.

I used following program to test/verify:

[snip]
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>

int main(int argc, char **argv)
{
        int fd, i;
        char *file = argv[1];

        if (-1 == (fd = open(file, O_WRONLY))) {
                perror("open failed");
                return -1;
        }

        for(i = 0; i < (argc - 2); i++) {
                int len = strlen(argv[2+i]);
                int cnt, off = 0;

                while(len) {
                        cnt = write(fd, argv[2+i] + off, len);
                        len -= cnt;
                        off += cnt;
                }
        }

        close(fd);
        return 0;
}
[snip]

before change:
sh-4.0# echo > ./set_ftrace_filter
sh-4.0# /test ./set_ftrace_filter "sys" "_open "
sh-4.0# cat ./set_ftrace_filter
#### all functions enabled ####
sh-4.0#

after change:
sh-4.0# echo > ./set_ftrace_notrace
sh-4.0# test ./set_ftrace_notrace "sys" "_open "
sh-4.0# cat ./set_ftrace_notrace
sys_open
sh-4.0#

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <20090811152904.GA26065@jolsa.lab.eng.brq.redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Jiri Olsa 2009-08-11 17:29:04 +02:00 committed by Steven Rostedt
parent f2d84b65b9
commit eda1e32855
1 changed files with 11 additions and 6 deletions
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17
kernel/trace/ftrace.c
View file

@ -2278,7 +2278,11 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
read++;
cnt--;
if (!(iter->flags & ~FTRACE_ITER_CONT)) {
/*
* If the parser haven't finished with the last write,
* continue reading the user input without skipping spaces.
*/
if (!(iter->flags & FTRACE_ITER_CONT)) {
/* skip white space */
while (cnt && isspace(ch)) {
ret = get_user(ch, ubuf++);
@ -2288,8 +2292,9 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
cnt--;
}
/* only spaces were written */
if (isspace(ch)) {
file->f_pos += read;
*ppos += read;
ret = read;
goto out;
}
@ -2319,12 +2324,12 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
if (ret)
goto out;
iter->buffer_idx = 0;
} else
} else {
iter->flags |= FTRACE_ITER_CONT;
iter->buffer[iter->buffer_idx++] = ch;
}
file->f_pos += read;
*ppos += read;
ret = read;
out:
mutex_unlock(&ftrace_regex_lock);