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Date:   Fri, 1 Feb 2019 15:21:09 +0100
From:   "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
To:     Maninder Singh <maninder1.s@samsung.com>
Cc:     "peter@hurleysoftware.com" <peter@hurleysoftware.com>,
        "jslaby@suse.com" <jslaby@suse.com>,
        "keun-o.park@darkmatter.ae" <keun-o.park@darkmatter.ae>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        AMIT SAHRAWAT <a.sahrawat@samsung.com>,
        Vaneet Narang <v.narang@samsung.com>,
        Rohit Thapliyal <r.thapliyal@samsung.com>,
        Ayush Mittal <ayush.m@samsung.com>
Subject: Re: race between flush_to_ldisc and pty_cleanup
Message-ID: <20190201142109.GA3211@kroah.com>
References: <CGME20190201133326epcms5p506416bc4ae22f600ee705f146ca1a599@epcms5p5>
 <20190201133326epcms5p506416bc4ae22f600ee705f146ca1a599@epcms5p5>
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On Fri, Feb 01, 2019 at 07:03:26PM +0530, Maninder Singh wrote:
> Hi,
> 
> 
> There is some race condition between tty_port_put and flush_to_ldisc
> which lead to use after free case:
> (Kernel 4.1)

Wait, 4.1 is _REALLY_ old and obsolete and broken in numerous known
places.

Can you duplicate this on 4.20, or better yet, 5.0-rc4?  Lots of tty and
ldisc fixes has gone into the tree in the past 3 1/2 years since that
kernel was released.

thanks,

greg k-h