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2588aba002
pch_uart_interrupt() takes priv->port.lock which leads to two recursive spinlock calls if low_latency==1 or CONFIG_PREEMPT_RT_FULL=y (one otherwise): pch_uart_interrupt spin_lock_irqsave(priv->port.lock, flags) case PCH_UART_IID_RDR_TO (data ready) handle_rx_to push_rx tty_port_tty_get spin_lock_irqsave(&port->lock, flags) <--- already hold this lock ... tty_flip_buffer_push ... flush_to_ldisc spin_lock_irqsave(&tty->buf.lock) spin_lock_irqsave(&tty->buf.lock) disc->ops->receive_buf(tty, char_buf) n_tty_receive_buf tty->ops->flush_chars() uart_flush_chars uart_start spin_lock_irqsave(&port->lock) <--- already hold this lock Avoid this by using a dedicated lock to protect the eg20t_port structure and IO access to its membase. This is more consistent with the 8250 driver. Ensure priv->lock is always take prior to priv->port.lock when taken at the same time. V2: Remove inadvertent whitespace change. V3: Account for oops_in_progress for the private lock in pch_console_write(). Note: Like the 8250 driver, if a printk is introduced anywhere inside the pch_console_write() critical section, the kernel will hang on a recursive spinlock on the private lock. The oops case is handled by using a trylock in the oops_in_progress case. Signed-off-by: Darren Hart <dvhart@linux.intel.com> CC: Tomoya MORINAGA <tomoya.rohm@gmail.com> CC: Feng Tang <feng.tang@intel.com> CC: Alexander Stein <alexander.stein@systec-electronic.com> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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.. | ||
hvc | ||
ipwireless | ||
serial | ||
vt | ||
amiserial.c | ||
bfin_jtag_comm.c | ||
cyclades.c | ||
ehv_bytechan.c | ||
isicom.c | ||
Kconfig | ||
Makefile | ||
moxa.c | ||
moxa.h | ||
mxser.c | ||
mxser.h | ||
n_gsm.c | ||
n_hdlc.c | ||
n_r3964.c | ||
n_tracerouter.c | ||
n_tracesink.c | ||
n_tracesink.h | ||
n_tty.c | ||
nozomi.c | ||
pty.c | ||
rocket_int.h | ||
rocket.c | ||
rocket.h | ||
synclink_gt.c | ||
synclink.c | ||
synclinkmp.c | ||
sysrq.c | ||
tty_audit.c | ||
tty_buffer.c | ||
tty_io.c | ||
tty_ioctl.c | ||
tty_ldisc.c | ||
tty_mutex.c | ||
tty_port.c |