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 <ard.biesheuvel@linaro.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
str r8, [r2] @ Save atags pointer
cmp r3, #0
strne r10, [r3] @ Save control register values
+ mov lr, #0
b start_kernel
ENDPROC(__mmap_switched)