v2 of this patch was sent (rebased on top of recent sources). On Thu, Apr 30, 2015 at 6:28 PM, Semen Protsenko <semen.protsenko@xxxxxxxxxxxxxxx> wrote: > There is pm_qos_add_request() being executed on serial_omap_probe(), > which stores "&up->pm_qos_request" from omap-serial driver to > "pm_qos_array[PM_QOS_CPU_DMA_LATENCY]->constraints". If > serial_omap_probe() fails after pm_qos_add_request() (e.g. on > uart_add_one_port() call), pm_qos_array still keeping pm_qos_request > struct from omap-serial driver, which is not valid anymore (since driver > failed). This leads further to kernel crash on pm_qos_update_target(), > executing from some completely different driver. > > We were observing this while trying to run audio playback while having > one of omap-serial driver instances failed on uart_add_one_port() call: > Unable to handle kernel paging request at virtual address fffffffc > Backtrace: > (plist_add) from (pm_qos_update_target) > (pm_qos_update_target) from (pm_qos_add_request) > (pm_qos_add_request) from (snd_pcm_hw_params) > (snd_pcm_hw_params) from (snd_pcm_common_ioctl1) > (snd_pcm_common_ioctl1) from (snd_pcm_playback_ioctl1) > (snd_pcm_playback_ioctl1) from (snd_pcm_playback_ioctl) > (snd_pcm_playback_ioctl) from (do_vfs_ioctl) > (do_vfs_ioctl) from (SyS_ioctl) > (SyS_ioctl) from (ret_fast_syscall) > > This patch adds pm_qos_remove_request() on fail path in > serial_omap_probe() in order to fix this issue. While at it, free the > wakeup settings on fail path as well, just like it's done in > serial_omap_remove(). > > Signed-off-by: Semen Protsenko <semen.protsenko@xxxxxxxxxxxxxxx> > --- > drivers/tty/serial/omap-serial.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c > index d55714d..8d03486 100644 > --- a/drivers/tty/serial/omap-serial.c > +++ b/drivers/tty/serial/omap-serial.c > @@ -1761,6 +1761,8 @@ static int serial_omap_probe(struct platform_device *pdev) > err_add_port: > pm_runtime_put(&pdev->dev); > pm_runtime_disable(&pdev->dev); > + pm_qos_remove_request(&up->pm_qos_request); > + device_init_wakeup(up->dev, false); > err_rs485: > err_port_line: > dev_err(&pdev->dev, "[UART%d]: failure [%s]: %d\n", > -- > 1.7.9.5 > -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
