Messages in this thread Patch in this message | | | Date | Mon, 27 Nov 2017 15:51:04 -0500 (EST) | From | Nicolas Pitre <> | Subject | Re: mm/percpu.c: use smarter memory allocation for struct pcpu_alloc_info (crisv32 hang) |
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On Mon, 27 Nov 2017, Tejun Heo wrote:
> Hello, > > On Mon, Nov 27, 2017 at 03:31:52PM -0500, Nicolas Pitre wrote: > > So IMHO I don't think reverting the commit is the right thing to do. > > That commit is clearly not at fault here. > > It's not about the blame. We just want to avoid breaking boot in a > way which is difficult to debug. Once cris is fixed, we can re-apply > the patch.
In that case I suggest the following instead. No point penalizing everyone for a single architecture's fault. And this will serve as a visible reminder to the cris people that they need to clean up.
----- >8 Subject: percpu: hack to let the CRIS architecture to boot until they clean up
Commit 438a506180 ("percpu: don't forget to free the temporary struct pcpu_alloc_info") uncovered a problem on the CRIS architecture where the bootmem allocator is initialized with virtual addresses. Given it has:
#define __va(x) ((void *)((unsigned long)(x) | 0x80000000))
then things just work out because the end result is the same whether you give this a physical or a virtual address.
Untill you call memblock_free_early(__pa(address)) that is, because values from __pa() don't match with the virtual addresses stuffed in the bootmem allocator anymore.
Avoid freeing the temporary pcpu_alloc_info memory on that architecture until they fix things up to let the kernel boot like it did before.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
diff --git a/mm/percpu.c b/mm/percpu.c index 79e3549cab..50e7fdf840 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -2719,7 +2719,11 @@ void __init setup_per_cpu_areas(void) if (pcpu_setup_first_chunk(ai, fc) < 0) panic("Failed to initialize percpu areas."); +#ifdef CONFIG_CRIS +#warning "the CRIS architecture has physical and virtual addresses confused" +#else pcpu_free_alloc_info(ai); +#endif } #endif /* CONFIG_SMP */
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