4.20-stable review patch. If anyone has any objections, please let me know.
------------------ From: Paul Fulghum <[email protected]> commit fc01d8c61ce02c034e67378cd3e645734bc18c8c upstream. 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 <[email protected]> Reported-by: syzbot <[email protected]> Cc: Tetsuo Handa <[email protected]> Cc: Alan Cox <[email protected]> Cc: stable <[email protected]> Acked-by: Arnd Bergmann <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/tty/n_hdlc.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/tty/n_hdlc.c +++ b/drivers/tty/n_hdlc.c @@ -597,6 +597,7 @@ static ssize_t n_hdlc_tty_read(struct tt /* 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
