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authorPaul Fulghum <paulkf@microgate.com>2019-01-01 12:28:53 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-01-18 13:27:54 +0100
commitfc01d8c61ce02c034e67378cd3e645734bc18c8c (patch)
tree12229d9297234109fa24748654ea15c908c6073e /drivers/tty
parent352c4cf40c4a7d439fa5d30aa2160f54b394da82 (diff)
downloadlinux-fc01d8c61ce02c034e67378cd3e645734bc18c8c.tar.gz
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@microgate.com>
Reported-by: syzbot <syzbot+c244af085a0159d22879@syzkaller.appspotmail.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: stable <stable@vger.kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/n_hdlc.c1
1 files changed, 1 insertions, 0 deletions
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