This is a note to let you know that I've just added the patch titled
tty/n_hdlc: fix __might_sleep warning
to my tty git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From fc01d8c61ce02c034e67378cd3e645734bc18c8c Mon Sep 17 00:00:00 2001
From: Paul Fulghum <paulkf@xxxxxxxxxxxxx>
Date: Tue, 1 Jan 2019 12:28:53 -0800
Subject: tty/n_hdlc: fix __might_sleep warning
Fix __might_sleep warning[1] in tty/n_hdlc.c read due to copy_to_user
call while current is TASK_INTERRUPTIBLE. This is a false positive
since the code path does not depend on current state remaining
TASK_INTERRUPTIBLE. The loop breaks out and sets TASK_RUNNING after
calling copy_to_user.
This patch supresses the warning by setting TASK_RUNNING before calling
copy_to_user.
[1] https://syzkaller.appspot.com/bug?id=17d5de7f1fcab794cb8c40032f893f52de899324
Signed-off-by: Paul Fulghum <paulkf@xxxxxxxxxxxxx>
Reported-by: syzbot <syzbot+c244af085a0159d22879@xxxxxxxxxxxxxxxxxxxxxxxxx>
Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Acked-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/n_hdlc.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c
index 4164414d4c64..8bdf42bc8fc8 100644
--- a/drivers/tty/n_hdlc.c
+++ b/drivers/tty/n_hdlc.c
@@ -597,6 +597,7 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file,
/* too large for caller's buffer */
ret = -EOVERFLOW;
} else {
+ __set_current_state(TASK_RUNNING);
if (copy_to_user(buf, rbuf->buf, rbuf->count))
ret = -EFAULT;
else
--
2.20.1
