Messages in this thread Patch in this message | | | Subject | Re: [BUG][2.6.8.1] serial driver hangs SMP kernel, but not the UP kernel | From | Paul Fulghum <> | Date | Fri, 29 Oct 2004 16:08:37 -0500 |
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On Fri, 2004-10-29 at 14:55, Tim_T_Murphy@Dell.com wrote: > Oct 29 13:34:48 racjag-1 chat[3886]: expect (CLIENTSERVER) > Oct 29 13:34:48 racjag-1 kernel: drivers/serial/serial_core.c:102: spin_lock(drivers/serial/serial_core.c:023f2548) already locked by drivers/serial/8250.c/1015 > Oct 29 13:34:48 racjag-1 kernel: drivers/serial/8250.c:1017: spin_unlock(drivers/serial/serial_core.c:023f2548) not locked > Oct 29 13:34:48 racjag-1 chat[3886]: CLIENTSERVER
One way this can happen is a receive interrupt:
serial8250_interrupt(); spin_lock(port->lock); serial8250_handle_port(); receive_chars(); flip.work.func(); /* if FLIP buffer full */ ldisc->receive_buf(); /* N_TTY */ tty->driver->flush_chars(); uart_start(); spin_lock(port->lock); *BANG*
Try the attached patch and report what happens.
-- Paul Fulghum paulkf@microgate.com
--- linux-2.6.8/drivers/serial/8250.c 2004-08-14 00:36:13.000000000 -0500 +++ b/drivers/serial/8250.c 2004-10-29 15:58:28.076014336 -0500 @@ -830,9 +830,13 @@ receive_chars(struct uart_8250_port *up, do { if (unlikely(tty->flip.count >= TTY_FLIPBUF_SIZE)) { - tty->flip.work.func((void *)tty); - if (tty->flip.count >= TTY_FLIPBUF_SIZE) - return; // if TTY_DONT_FLIP is set + /* no room in flip buffer, discard rx FIFO contents to clear IRQ */ + do { + serial_inp(up, UART_RX); + up->port.icount.overrun++; + *status = serial_inp(up, UART_LSR); + } while ((*status & UART_LSR_DR) && (max_count-- > 0)); + return; /* if TTY_DONT_FLIP is set */ } ch = serial_inp(up, UART_RX); *tty->flip.char_buf_ptr = ch;
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