Panic on reloading a driver with same DEVICE_PROBE() return value

[Sreekanth Reddy]

On Mon, Feb 8, 2016 at 11:58 PM, John Baldwin <jhb at freebsd.org> wrote:
> On Monday, February 08, 2016 08:13:26 PM Sreekanth Reddy wrote:
>> sc->facts = malloc(sizeof(MPI2_IOC_FACTS_REPLY), M_MPR, M_ZERO|M_NOWAIT);
>
> M_NOWAIT can fail with NULL.  Normally in an attach routine you should use a
> blocking malloc (M_WAITOK) which will not fail with NULL.

Yes I agree that in an attach routine we should to use a blocking
malloc (M_WAITOK) flag.

But, here I am observing same page fault even with (M_WAITOK) flag.

Here, page fault is occurring inside the malloc function and driver is
not receiving any NULL or any other value.

>
>> * How can I reload the modified driver with return same device_probe()
>> value as the one which has loaded during the OS boot time. I observed
>> that whenever I try to load this modified driver using "kldload
>> ./mpr.ko" command then I see that driver in the /boot/kernel/ path has
>> executed.
>
> At runtime you can use the devctl(8) command on HEAD (it will be included
> in 10.3) to force a device to detach/attach to force a re-probe.
>
> e.g.
>
> devctl detach mpr0
>
> # note that the device won't be named mpr0, you will need to use its PCI
> # location for this next:
>
> devctl attach pci0:4:0:0

I have started downloading the current kernel. I will verify this
today/tomorrow.


>
> --
> John Baldwin