diff options
| author | Gaurav Kohli <gkohli@codeaurora.org> | 2018-01-23 13:16:34 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-02-03 17:58:37 +0100 |
| commit | 3e1995ed770e780b423b31b160570bff2d4769d3 (patch) | |
| tree | 19ddf1d21ebf1521fead9ac93a195166ab4caea7 /include/linux | |
| parent | e880bc8b35f8874ad406f13f2701a104834a7b83 (diff) | |
tty: fix data race between tty_init_dev and flush of buf
commit b027e2298bd588d6fa36ed2eda97447fb3eac078 upstream.
There can be a race, if receive_buf call comes before
tty initialization completes in n_tty_open and tty->disc_data
may be NULL.
CPU0 CPU1
---- ----
000|n_tty_receive_buf_common() n_tty_open()
-001|n_tty_receive_buf2() tty_ldisc_open.isra.3()
-002|tty_ldisc_receive_buf(inline) tty_ldisc_setup()
Using ldisc semaphore lock in tty_init_dev till disc_data
initializes completely.
Signed-off-by: Gaurav Kohli <gkohli@codeaurora.org>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/tty.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/tty.h b/include/linux/tty.h index 7ac8ba208b1f..0a6c71e0ad01 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -405,6 +405,8 @@ extern const char *tty_name(const struct tty_struct *tty); extern struct tty_struct *tty_kopen(dev_t device); extern void tty_kclose(struct tty_struct *tty); extern int tty_dev_name_to_number(const char *name, dev_t *number); +extern int tty_ldisc_lock(struct tty_struct *tty, unsigned long timeout); +extern void tty_ldisc_unlock(struct tty_struct *tty); #else static inline void tty_kref_put(struct tty_struct *tty) { } |