[PATCH] ARM: head-common.S: Clear lr before jumping to start_kernel()
From: Nicolas Pitre <hidden>
Date: 2017-10-03 15:37:24
Also in:
linux-renesas-soc, lkml
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 <redacted>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>Good! This fixes another similar case I had but I didn't come around to look at closely yet. Acked-by: Nicolas Pitre <redacted> Please send it to RMK's patch system.
quoted hunk ↗ jump to hunk
--- Commit 9520b1a1b5f7a348 is in arm/for-next. arch/arm/kernel/head-common.S | 1 + 1 file changed, 1 insertion(+)diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S index a25027b87a6024b9..21dde771a7dd8d14 100644 --- a/arch/arm/kernel/head-common.S +++ b/arch/arm/kernel/head-common.S@@ -114,6 +114,7 @@ __mmap_switched: 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)-- 2.7.4