Messages in this thread | | | Date | Mon, 29 Aug 2022 12:36:24 +0300 (EEST) | From | Ilpo Järvinen <> | Subject | Re: 6.0 tty regression, NULL pointer deref in flush_to_ldisc |
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On Mon, 29 Aug 2022, Hans de Goede wrote:
> Hi All, > > This weekend I noticed that on various Bay Trail based systems which have > their bluetooth HCI connected over an uart (using hci_uart driver / > using the drivers/tty/serial bus) there is a NULL pointer deref in > flush_to_ldisc, see below for the full backtrace. > > I *suspect* that this is caused by commit 6bb6fa6908eb > ("tty: Implement lookahead to process XON/XOFF timely"). > > I can cleanly revert this by reverting the following commits: > > ab24a01b2765 ("tty: Add closing marker into comment in tty_ldisc.h") > 65534736d9a5 ("tty: Use flow-control char function on closing path") > 6bb6fa6908eb ("tty: Implement lookahead to process XON/XOFF timely") > > ATM I don't have one of the affected systems handy. I will give > a 6.0-rc3 kernel with these 3 commits reverted a try tonight (CEST) > and I'll let you know the results. > > Note I can NOT confirm yet that these reverts fix things, so please > don't revert anything yet. I just wanted to give people a headsup > about this issue. > > Also maybe we can fix the new lookahead code instead of reverting. > I would be happy to add a patch adding some debugging prints the > systems run fine after the backtrace as long as I don't suspend them > so gathering logs is easy.
I guess this will help:
https://lore.kernel.org/linux-kernel/20220818115026.2237893-1-vincent.whitchurch@axis.com/
-- i.
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