On Sat, Sep 26, 2020 at 11:00:46PM +0000, Mikolaj Kucharski wrote:
> On Wed, Sep 16, 2020 at 09:19:37PM +0000, Mikolaj Kucharski wrote:
> > So time of the crash varies and I guess probably there is no pattern
> > there. Here is new panic report, with some kernel printf()s added.
> >
> > Problem seems to be related that dataphyspage is greater than
> > dataphyslastpage: lastpage=0xa0e0000 page=0xa0e1000 phys=0xa0e1000.
> > The same is observable in all those previous panics.
> >
>
> Here ia nother analysis, without my patches, I think they may be
> confusing. I will show flow of ehci_alloc_sqtd_chain() with values
> of variables which I collected via my debugging effort.
>
> I think I have understanding what is the flow, but not sure what
> code should do in those circumstances.
>
I didn't get any feedback on this so far. I'm running custom kernel
with additional printf()'s to help me understand the flow.
I ended up with following diff, which I think is safe to do,
as code handles situation when curlen == 0 further down in
ehci_alloc_sqtd_chain() function. My machine runs more than
two weeks with below panic() removed and condition of panic
is triggered multiple times during uptime and I didn't notice
any side effects.
However, flow of ehci_alloc_sqtd_chain() is hard to follow. Well, for me
anyway. At this stage I don't know how to improve things, beyond below
diff.
Any feedback would be appreciated. I don't like running custom kernels,
so I would like to drop below M from my source checkout.
Index: ehci.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/ehci.c,v
retrieving revision 1.211
diff -u -p -u -r1.211 ehci.c
--- ehci.c 6 Aug 2020 14:06:12 -0000 1.211
+++ ehci.c 23 Oct 2020 10:00:35 -0000
@@ -2407,10 +2407,6 @@ ehci_alloc_sqtd_chain(struct ehci_softc
curlen -= curlen % mps;
DPRINTFN(1,("ehci_alloc_sqtd_chain: multiple QTDs, "
"curlen=%u\n", curlen));
-#ifdef DIAGNOSTIC
- if (curlen == 0)
- panic("ehci_alloc_std: curlen == 0");
-#endif
}
DPRINTFN(4,("ehci_alloc_sqtd_chain: dataphys=0x%08x "
--
Regards,
Mikolaj
