diff options
author | Al Viro <viro@zeniv.linux.org.uk> | 2011-09-09 23:14:02 (GMT) |
---|---|---|
committer | Richard Weinberger <richard@nod.at> | 2012-03-24 23:29:53 (GMT) |
commit | 31efcebb7d7196adcee73027f513d7c0bf572b47 (patch) | |
tree | c3064342091568bd66f1f5cd85b3c1972ed697da /arch/um/drivers | |
parent | d8c215adbf3901aa7d00a0f17f08d77be689f838 (diff) | |
download | linux-31efcebb7d7196adcee73027f513d7c0bf572b47.tar.xz |
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>
Diffstat (limited to 'arch/um/drivers')
-rw-r--r-- | arch/um/drivers/chan_kern.c | 3 | ||||
-rw-r--r-- | arch/um/drivers/line.c | 54 |
2 files changed, 29 insertions, 28 deletions
diff --git a/arch/um/drivers/chan_kern.c b/arch/um/drivers/chan_kern.c index 420e2c8..3a95498 100644 --- a/arch/um/drivers/chan_kern.c +++ b/arch/um/drivers/chan_kern.c @@ -551,6 +551,9 @@ int parse_chan_pair(char *str, struct line *line, int device, INIT_LIST_HEAD(chans); } + if (!str) + return 0; + out = strchr(str, ','); if (out != NULL) { in = str; diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c index dc7e216..1a8d659 100644 --- a/arch/um/drivers/line.c +++ b/arch/um/drivers/line.c @@ -482,7 +482,7 @@ void close_lines(struct line *lines, int nlines) } 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]; int err = -EINVAL; @@ -494,13 +494,28 @@ static int setup_one_line(struct line *lines, int n, char *init, goto out; } - if (!strcmp(init, "none")) - line->valid = 0; - else { - line->init_str = init; + if (!strcmp(init, "none")) { + if (line->valid) { + line->valid = 0; + 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; + err = parse_chan_pair(new, line, n, opts, error_out); + if (err) { + line->init_str = NULL; + line->valid = 0; + kfree(new); + } } - err = 0; out: mutex_unlock(&line->count_lock); return err; @@ -549,10 +564,8 @@ out: int line_config(struct line *lines, unsigned int num, char *str, const struct chan_opts *opts, char **error_out) { - struct line *line; - char *new; char *end; - int n, err; + int n; if (*str == '=') { *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; } - new = kstrdup(end, GFP_KERNEL); - 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); + return setup_one_line(lines, n, end, opts, error_out); } 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"; 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, @@ -688,15 +692,9 @@ void lines_init(struct line *lines, int nlines, struct chan_opts *opts) if (line->init_str == NULL) continue; - line->init_str = kstrdup(line->init_str, GFP_KERNEL); - if (line->init_str == NULL) - 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 " + if (setup_one_line(lines, i, line->init_str, opts, &error)) + printk(KERN_ERR "setup_one_line failed for " "device %d : %s\n", i, error); - line->valid = 0; - } } } |