Hi James,
On 11.10.2019 12:38, James Morse wrote:
> Hi guys,
>
> On 11/10/2019 11:05, Sudeep Holla wrote:
>> On Fri, Oct 11, 2019 at 11:26:04AM +0200, Marek Szyprowski wrote:
>>> Recently I've got access to ARM Juno R1 board and did some tests with
>>> current mainline kernel on it. I'm a bit surprised that enabling
>>> CONFIG_PROVE_LOCKING causes a boot failure on this board. After enabling
>>> this Kconfig option, I get no single message from the kernel, although I
>>> have earlycon enabled.
>> I don't have Juno R1 but I tried defconfig + CONFIG_PROVE_LOCKING and
>> it boots fine.
> I just tried this on my r1, v5.4-rc1 with this configuration worked just fine.
>
> My cmdline is:
> | root=/dev/sda6 loglevel=9 earlycon=pl011,0x7ff80000 hugepagesz=2M
> hugepages=512
> | crashkernel=1G console=ttyAMA0 resume=/dev/sda2 no_console_suspend efi=debug
>
That is a bit strange. Here is a boot log from v5.4-rc1 with pure
defconfig: https://paste.debian.net/1105851/
The bisect lead me to the commit
c3bc8fd637a9623f5c507bd18f9677effbddf584 ("tracing: Centralize
preemptirq tracepoints and unify their usage"), which appeared in
v4.19-rc1. It cannot be easily reverted, but kernel built from earlier
versions boots fine here with PROVE_LOCKING enabled. I wonder what I do
in a different way than You...
>>> I've did my test with default defconfig and current linux-next,
>>> v5.4-rc1, v5.3 and v4.19. In all cases the result is the same. I'm
>>> booting kernel using a precompiled uboot from Linaro release and TFTP
>>> download.
>> OK, I use UEFI+GRUB but I don't think that should cause any issue.
> ... same ... this uboot binary looks like the main difference.
> Is it using u-boots UEFI support? Is it possible to turn that off?
>
> It may that lockdep is just perturbing the size of the binary. It adds an
> extra 4MB for me.
The size of the kernel binary doesn't matter. I've successfully booted
larger images, than the once compiled with PROVE_LOCKING enabled.
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
