Messages in this thread | | | Date | Fri, 7 Jan 2022 10:53:54 +0000 | From | Catalin Marinas <> | Subject | Re: [PATCH v3] arm64/mm: avoid fixmap race condition when create pud mapping |
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On Fri, Jan 07, 2022 at 09:10:57AM +0000, Jianyong Wu wrote: > I roughly find the root cause. > alloc_init_pud will be called at the very beginning of kernel boot in > create_mapping_noalloc where no memory allocator is initialized. But > lockdep check may need allocate memory. So, kernel take exception > when acquire lock.(I have not found the exact code that cause this > issue) that's say we may not be able to use a lock so early.
I couldn't find an slab or page allocation place either. It would be nice to get to the root cause rather than just avoiding the mutex on the early boot path.
-- Catalin
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