Re: [PATCH v2] tty: serial: meson: hard LOCKUP on crtscts mode

From: Greg Kroah-Hartman
Date: Thu Oct 12 2023 - 09:30:11 EST


On Thu, Oct 12, 2023 at 01:22:41PM +0000, pkrasavin@xxxxxxxxxx wrote:
> There might be hard lockup if we set crtscts mode on port without RTS/CTS configured:
>
> # stty -F /dev/ttyAML6 crtscts; echo 1 > /dev/ttyAML6; echo 2 > /dev/ttyAML6
> [ 95.890386] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
> [ 95.890857] rcu: 3-...0: (201 ticks this GP) idle=e33c/1/0x4000000000000000 softirq=5844/5846 fqs=4984
> [ 95.900212] rcu: (detected by 2, t=21016 jiffies, g=7753, q=296 ncpus=4)
> [ 95.906972] Task dump for CPU 3:
> [ 95.910178] task:bash state:R running task stack:0 pid:205 ppid:1 flags:0x00000202
> [ 95.920059] Call trace:
> [ 95.922485] __switch_to+0xe4/0x168
> [ 95.925951] 0xffffff8003477508
> [ 95.974379] watchdog: Watchdog detected hard LOCKUP on cpu 3
> [ 95.974424] Modules linked in: 88x2cs(O) rtc_meson_vrtc
>
> Possible solution would be to not allow to setup crtscts on such port.
>
> Tested on S905X3 based board.
>
> Signed-off-by: Pavel Krasavin <pkrasavin@xxxxxxxxxxx>


Hi,

This is the friendly patch-bot of Greg Kroah-Hartman. You have sent him
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