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um: fix races between line_open() and line_config() 

Pull parse_chan_pair() call into setup_one_line(), under the mutex.
We really don't want open() to succeed before parse_chan_pair() had
been done (or after it has failed, BTW).  We also want "remove con<n>"
to free irqs, etc., same as "config con<n>=none".

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Al Viro 2011-09-09 19:14:02 -04:00 committed by Richard Weinberger
parent d8c215adbf
commit 31efcebb7d
2 changed files with 29 additions and 28 deletions
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3
arch/um/drivers/chan_kern.c
View File

@ -551,6 +551,9 @@ int parse_chan_pair(char *str, struct line *line, int device,
INIT_LIST_HEAD(chans); INIT_LIST_HEAD(chans);
} }
if (!str)
return 0;
out = strchr(str, ','); out = strchr(str, ',');
if (out != NULL) { if (out != NULL) {
in = str; in = str;

54
arch/um/drivers/line.c
View File

@ -482,7 +482,7 @@ void close_lines(struct line *lines, int nlines)
} }
static int setup_one_line(struct line *lines, int n, char *init, static int setup_one_line(struct line *lines, int n, char *init,
char **error_out) const struct chan_opts *opts, char **error_out)
{ {
struct line *line = &lines[n]; struct line *line = &lines[n];
int err = -EINVAL; int err = -EINVAL;
@ -494,13 +494,28 @@ static int setup_one_line(struct line *lines, int n, char *init,
goto out; goto out;
} }
if (!strcmp(init, "none")) if (!strcmp(init, "none")) {
line->valid = 0; if (line->valid) {
else { line->valid = 0;
line->init_str = init; kfree(line->init_str);
parse_chan_pair(NULL, line, n, opts, error_out);
err = 0;
}
} else {
char *new = kstrdup(init, GFP_KERNEL);
if (!new) {
*error_out = "Failed to allocate memory";
return -ENOMEM;
}
line->init_str = new;
line->valid = 1; line->valid = 1;
err = parse_chan_pair(new, line, n, opts, error_out);
if (err) {
line->init_str = NULL;
line->valid = 0;
kfree(new);
}
} }
err = 0;
out: out:
mutex_unlock(&line->count_lock); mutex_unlock(&line->count_lock);
return err; return err;
@ -549,10 +564,8 @@ out:
int line_config(struct line *lines, unsigned int num, char *str, int line_config(struct line *lines, unsigned int num, char *str,
const struct chan_opts *opts, char **error_out) const struct chan_opts *opts, char **error_out)
{ {
struct line *line;
char *new;
char *end; char *end;
int n, err; int n;
if (*str == '=') { if (*str == '=') {
*error_out = "Can't configure all devices from mconsole"; *error_out = "Can't configure all devices from mconsole";
@ -569,16 +582,7 @@ int line_config(struct line *lines, unsigned int num, char *str,
return -EINVAL; return -EINVAL;
} }
new = kstrdup(end, GFP_KERNEL); return setup_one_line(lines, n, end, opts, error_out);
if (new == NULL) {
*error_out = "Failed to allocate memory";
return -ENOMEM;
}
err = setup_one_line(lines, n, new, error_out);
if (err)
return err;
line = &lines[n];
return parse_chan_pair(line->init_str, line, n, opts, error_out);
} }
int line_get_config(char *name, struct line *lines, unsigned int num, char *str, int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
@ -633,7 +637,7 @@ int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
*error_out = "Device number out of range"; *error_out = "Device number out of range";
return -EINVAL; return -EINVAL;
} }
return setup_one_line(lines, n, "none", error_out); return setup_one_line(lines, n, "none", NULL, error_out);
} }
struct tty_driver *register_lines(struct line_driver *line_driver, struct tty_driver *register_lines(struct line_driver *line_driver,
@ -688,15 +692,9 @@ void lines_init(struct line *lines, int nlines, struct chan_opts *opts)
if (line->init_str == NULL) if (line->init_str == NULL)
continue; continue;
line->init_str = kstrdup(line->init_str, GFP_KERNEL); if (setup_one_line(lines, i, line->init_str, opts, &error))
if (line->init_str == NULL) printk(KERN_ERR "setup_one_line failed for "
printk(KERN_ERR "lines_init - kstrdup returned NULL\n");
if (parse_chan_pair(line->init_str, line, i, opts, &error)) {
printk(KERN_ERR "parse_chan_pair failed for "
"device %d : %s\n", i, error); "device %d : %s\n", i, error);
line->valid = 0;
}
} }
} }