On Tue, Jun 11, 2013 at 4:15 PM, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > On Tue, Jun 11, 2013 at 04:03:07PM -0700, Stéphane Marchesin wrote: >> When quickly restarting X servers, we can run into a situation where >> one X server quits while another one starts on the same tty. For a >> while, two X servers share the tty, and when the old X server >> eventually quits, the tty layer hangs up the tty, which among other >> things stubs out the tty's ioctl functions. Later on, the new X >> server (which shares the tty functions) tries to call some ioctls >> on the tty and fails because they have been replaced with the hungup >> versions. This in turn causes the new X server to abort. >> >> This patch checks the tty->count to make sure we're the last >> consumer before hanging up a tty. >> >> Signed-off-by: Stéphane Marchesin <marcheu@xxxxxxxxxxxx> >> --- >> drivers/tty/tty_io.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c >> index 6464029..62a0f02 100644 >> --- a/drivers/tty/tty_io.c >> +++ b/drivers/tty/tty_io.c >> @@ -619,6 +619,9 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session) >> if (!tty) >> return; >> >> + /* Don't hangup if there are other users */ >> + if (tty->count > 1) >> + return; > > What happens when you have a "real" tty that was hungup because it was > disconnected physically from the system yet userspace had a tty open? > You want those ttys to be hungup properly, right? Doesn't this change > break that? My understanding was that they'd have a different tty_struct. Is that not the case? If so how would you recommend fixing the problem I described? Stéphane -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
