Hi John,
On Thu, Nov 13, 2025 at 06:12:57PM +0106, John Ogness wrote:
I assume the problem you are seeing is with the PREEMPT_RT patches applied (i.e. with the 8250-NBCON included). If that is the case, note that recent versions of the 8250 driver introduce its own irq_work that is also problematic. I am currently reworking the 8250-NBCON series so that it does not introduce irq_work.
IIRC the aforementioned scenario was just recently tested with an rc5 kernel from Torvalds' tree. Sorry for any confusion
Since you probably are not doing anything related to modem control, maybe you could test with the following hack (assuming you are using a v6.14 or later PREEMPT_RT patched kernel).
I'll give this a shot as a follow up, thanks for the suggestion
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 96d32db9f8872..2ad0f91ad467a 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -3459,7 +3459,7 @@ void serial8250_console_write(struct uart_8250_port *up, * may be a context that does not permit waking up tasks. */ if (is_atomic)
irq_work_queue(&up->modem_status_work);
;//irq_work_queue(&up->modem_status_work);[0] https://github.com/Linutronix/linux/commit/ae173249d9028ef159fba040bdab260d8...
John