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Commit 31efcebb authored by Al Viro's avatar Al Viro Committed by Richard Weinberger
Browse files

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: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
parent d8c215ad

arch/um/drivers/chan_kern.c

+3 −0
Original line number Original line Diff line number Diff line
@@ -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;

arch/um/drivers/line.c

+26 −28
Original line number Original line Diff line number Diff line
@@ -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")) {

		if (line->valid) {

			line->valid = 0;

			line->valid = 0;

	else {

			kfree(line->init_str);

		line->init_str = init;

			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 @@ int line_setup(char **conf, unsigned int num, char **def, 
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;

		}

	}

	}

}

}