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Subject答复: [PATCH][v2] tty: fix race between flu sh to ldisc and tty open
> -----邮件原件-----
> 发件人: Kohli, Gaurav []
> 发送时间: 2019年1月11日 21:57
> 收件人: Li,Rongqing <>;;
> 主题: Re: [PATCH][v2] tty: fix race between flush_to_ldisc and tty_open
> Hi,
> it don't seems to be good idea to put lock on one function and unlock in some
> other function. If in future some one has to call tty_init_dev, how he can track
> the unlocking as well of ldisc lock.
> Regards
> Gaurav

This similar condition has existed for a long time, tty_unlock(tty) must be called in
some other functions who call tty_init_dev, since tty_init_dev hold tty_lock, and does
not release it

so I think it is user responsibility to fully understand tty_init_dev; and I can add some
comments for tty_init_dev if this patch can be acceptable;

or a workaround like below:
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index a42a028a9d4e..2f5ad256b6ad 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -425,7 +425,7 @@ static void flush_to_ldisc(struct work_struct *work)
struct tty_ldisc *disc;

tty = port->itty;
- if (tty == NULL)
+ if (tty == NULL || tty->driver_data == NULL)

disc = tty_ldisc_ref(tty);


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