diff options
| author |   Alan Cox <alan@lxorguk.ukuu.org.uk> | 2008-04-30 00:53:31 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-30 08:29:40 -0700 |
| commit | 5d0fdf1e01899805b6c2c0b789a707dcb731b1ea (patch) | |
| tree | 19827c7b3cf365c0b403741ead6c7bc317cad51b | |
| parent | Resume TTY on SUSP and fix CRNL order in N_TTY line discipline (diff) | |
| download | linux-dev-5d0fdf1e01899805b6c2c0b789a707dcb731b1ea.tar.xz linux-dev-5d0fdf1e01899805b6c2c0b789a707dcb731b1ea.zip | |
tty_io: fix remaining pid struct locking
This fixes the last couple of pid struct locking failures I know about.
[oleg@tv-sign.ru: clean up do_task_stat()]
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | drivers/char/tty_io.c | 28 | ||||
| -rw-r--r-- | fs/proc/array.c | 4 | ||||
| -rw-r--r-- | include/linux/tty.h | 1 |
3 files changed, 31 insertions, 2 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index c8aa318eaa18..2460c4c76161 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -3174,6 +3174,27 @@ unlock: } /** + * tty_get_pgrp - return a ref counted pgrp pid + * @tty: tty to read + * + * Returns a refcounted instance of the pid struct for the process + * group controlling the tty. + */ + +struct pid *tty_get_pgrp(struct tty_struct *tty) +{ + unsigned long flags; + struct pid *pgrp; + + spin_lock_irqsave(&tty->ctrl_lock, flags); + pgrp = get_pid(tty->pgrp); + spin_unlock_irqrestore(&tty->ctrl_lock, flags); + + return pgrp; +} +EXPORT_SYMBOL_GPL(tty_get_pgrp); + +/** * tiocgpgrp - get process group * @tty: tty passed by user * @real_tty: tty side of the tty pased by the user if a pty else the tty @@ -3187,13 +3208,18 @@ unlock: static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) { + struct pid *pid; + int ret; /* * (tty == real_tty) is a cheap way of * testing if the tty is NOT a master pty. */ if (tty == real_tty && current->signal->tty != real_tty) return -ENOTTY; - return put_user(pid_vnr(real_tty->pgrp), p); + pid = tty_get_pgrp(real_tty); + ret = put_user(pid_vnr(pid), p); + put_pid(pid); + return ret; } /** diff --git a/fs/proc/array.c b/fs/proc/array.c index b07a71002f2f..c135cbdd9127 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -429,7 +429,9 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, struct signal_struct *sig = task->signal; if (sig->tty) { - tty_pgrp = pid_nr_ns(sig->tty->pgrp, ns); + struct pid *pgrp = tty_get_pgrp(sig->tty); + tty_pgrp = pid_nr_ns(pgrp, ns); + put_pid(pgrp); tty_nr = new_encode_dev(tty_devnum(sig->tty)); } diff --git a/include/linux/tty.h b/include/linux/tty.h index 381085e45cca..2699298b00ef 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -297,6 +297,7 @@ extern int tty_read_raw_data(struct tty_struct *tty, unsigned char *bufp, extern void tty_write_message(struct tty_struct *tty, char *msg); extern int is_current_pgrp_orphaned(void); +extern struct pid *tty_get_pgrp(struct tty_struct *tty); extern int is_ignored(int sig); extern int tty_signal(int sig, struct tty_struct *tty); extern void tty_hangup(struct tty_struct * tty); |