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SubjectRe: [PATCH] ARM: head-common.S: Clear lr before jumping to start_kernel()
On Tue, Oct 3, 2017 at 5:37 PM, Nicolas Pitre <> wrote:
> On Tue, 3 Oct 2017, Geert Uytterhoeven wrote:
>> If CONFIG_DEBUG_LOCK_ALLOC=y, the kernel log is spammed with a few
>> hundred identical messages:
>> unwind: Unknown symbol address c0800300
>> unwind: Index not found c0800300
>> c0800300 is the return address from the last subroutine call (to
>> __memzero()) in __mmap_switched(). Apparently having this address in
>> the link register confuses the unwinder.
>> To fix this, reset the link register to zero before jumping to
>> start_kernel().
>> Fixes: 9520b1a1b5f7a348 ("ARM: head-common.S: speed up startup code")
>> Suggested-by: Ard Biesheuvel <>
>> Signed-off-by: Geert Uytterhoeven <>
> Good! This fixes another similar case I had but I didn't come around to
> look at closely yet.
> Acked-by: Nicolas Pitre <>


> Please send it to RMK's patch system.

Done (I hope so ;-)



Geert Uytterhoeven -- There's lots of Linux beyond ia32 --

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

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