| Date | Wed, 22 Nov 2017 08:43:52 +0100 | From | Ingo Molnar <> | Subject | Re: WARNING: can't dereference registers at ffffc90004dfff60 for ip error_entry+0x7d/0xd0 (Re: [PATCH v2 00/18] Entry stack switching) |
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* Ingo Molnar <mingo@kernel.org> wrote:
> > * Andy Lutomirski <luto@kernel.org> wrote: > > > This sets up stack switching, including for SYSCALL. I think it's > > in decent shape. > > > > Known issues: > > - I think we're going to want a way to turn the stack switching on and > > off either at boot time or at runtime. It should be fairly straightforward > > to make it work. > > > > - I think the ORC unwinder isn't so good at dealing with stack overflows. > > It bails too early (I think), resulting in lots of ? entries. This > > isn't a regression with this series -- it's just something that could > > be improved. > > Note that with the attached config on an Intel testbox I get the following new ORC > unwinder warning during bootup: > > [ 12.200554] calling ghash_pclmulqdqni_mod_init+0x0/0x54 @ 1 > [ 12.209536] WARNING: can't dereference registers at ffffc90004dfff60 for ip error_entry+0x7d/0xd0 > [ 12.231388] initcall ghash_pclmulqdqni_mod_init+0x0/0x54 returned 0 after 23480 usecs > > Thanks,
Also note that the ORC warning goes away if CONFIG_PROVE_LOCKING is disabled.
Thanks,
Ingo
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