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From: Samuel Thibault <samuel.thibault@ens-lyon.org>
To: Matthias Reichl <hias@horus.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>,
	speakup@linux-speakup.org, linux-serial@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: Crash when specifying non-existent serial port in speakup / tty_kopen
Date: Wed, 4 Nov 2020 22:30:05 +0100	[thread overview]
Message-ID: <20201104213005.khivjvcwkaz7kz4g@function> (raw)
In-Reply-To: <20201104211504.GA20012@lenny.lan>

Matthias Reichl, le mer. 04 nov. 2020 22:15:05 +0100, a ecrit:
> > This looks like only a warning, did it actually crash?
> 
> Yes, scroll down a bit, the null pointer oops followed almost
> immediately after that
> 
> [   49.979043] BUG: kernel NULL pointer dereference, address: 0000000000000090

Ah, [   50.102938]  tty_init_dev+0xb5/0x1d0

probably the trailing release_tty call that does

tty->port->itty = NULL;
(itty is after a struct tty_bufhead + the tty pointer, that looks
plausible).

so probably an if (tty->port) in release_tty could help?

Samuel

  reply	other threads:[~2020-11-04 21:30 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-04 14:57 Crash when specifying non-existent serial port in speakup / tty_kopen Matthias Reichl
2020-11-04 20:13 ` Samuel Thibault
2020-11-04 21:15   ` Matthias Reichl
2020-11-04 21:30     ` Samuel Thibault [this message]
2020-11-05 12:21       ` Matthias Reichl

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