Messages in this thread |  | | Date | Sat, 1 Jun 2019 09:18:36 -0700 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH AUTOSEL 4.4 50/56] tty: pty: Fix race condition between release_one_tty and pty_write |
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On Sat, Jun 01, 2019 at 09:17:07AM -0700, Greg Kroah-Hartman wrote: > On Sat, Jun 01, 2019 at 09:25:54AM -0400, Sasha Levin wrote: > > From: Sahara <keun-o.park@darkmatter.ae> > > > > [ Upstream commit b9ca5f8560af244489b4a1bc1ae88b341f24bc95 ] > > > > Especially when a linked tty is used such as pty, the linked tty > > port's buf works have not been cancelled while master tty port's > > buf work has been cancelled. Since release_one_tty and flush_to_ldisc > > run in workqueue threads separately, when pty_cleanup happens and > > link tty port is freed, flush_to_ldisc tries to access freed port > > and port->itty, eventually it causes a panic. > > This patch utilizes the magic value with holding the tty_mutex to > > check if the tty->link is valid. > > > > Fixes: 2b022ab7542d ("pty: cancel pty slave port buf's work in tty_release") > > Signed-off-by: Sahara <keun-o.park@darkmatter.ae> > > Cc: stable <stable@vger.kernel.org> > > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > Signed-off-by: Sasha Levin <sashal@kernel.org> > > --- > > drivers/tty/pty.c | 7 +++++++ > > drivers/tty/tty_io.c | 3 +++ > > 2 files changed, 10 insertions(+) > > For some reason I did not apply this to the stable kernels, and this > shouldn't only be for 4.4.y, so please drop this.
Ah, I never applied it because it was later reverted, also upstream, 0eae4686a128 ("Revert "tty: pty: Fix race condition between release_one_tty and pty_write""), so I didn't apply both of them to the stable trees as that wouldn't have made sense.
thanks,
greg k-h
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