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authorGaurav Kohli <gkohli@codeaurora.org>2018-01-23 13:16:34 +0530
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-01-23 08:57:37 +0100
commitb027e2298bd588d6fa36ed2eda97447fb3eac078 (patch)
tree3b90cee88ac74c2828b90b67d67cf7adf6e9e310 /include/linux/tty.h
parent09df0b3464e528c6a4ca2c48d9ff6d2fd7cbd775 (diff)
tty: fix data race between tty_init_dev and flush of buf
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> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/tty.h')
-rw-r--r--include/linux/tty.h2
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)
{ }