Re: [RFC/PATCH RESEND -next 01/21] Add kernel address sanitizer infrastructure.

From: Andrey Ryabinin
Date: Thu Jul 10 2014 - 15:04:41 EST


2014-07-10 18:02 GMT+04:00 Sasha Levin <sasha.levin@xxxxxxxxxx>:
> On 07/10/2014 09:39 AM, Andrey Ryabinin wrote:
>>> Anyways, the machine won't boot with more than 1GB of RAM, is there a solution to
>>> > get KASAN running on my machine?
>>> >
>> Could you share you .config? I'll try to boot it by myself. It could be that some options conflicting with kasan.
>> Also boot cmdline might help.
>>
>
> Sure. It's the .config I use for fuzzing so it's rather big (attached).
>
> The cmdline is:
>
> [ 0.000000] Command line: noapic noacpi pci=conf1 reboot=k panic=1 i8042.direct=1 i8042.dumbkbd=1 i8042.nopnp=1 console=ttyS0 earlyprintk=serial i8042.noaux=1 numa=fake=32 init=/virt/init zcache ftrace_dump_on_oops debugpat kvm.mmu_audit=1 slub_debug=FZPU rcutorture.rcutorture_runnable=0 loop.max_loop=64 zram.num_devices=4 rcutorture.nreaders=8 oops=panic nr_hugepages=1000 numa_balancing=enable softlockup_all_cpu_backtrace=1 root=/dev/root rw rootflags=rw,trans=virtio,version=9p2000.L rootfstype=9p init=/virt/init
>
> And the memory map:
>
> [ 0.000000] e820: BIOS-provided physical RAM map:
> [ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
> [ 0.000000] BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
> [ 0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000ffffe] reserved
> [ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x00000000cfffffff] usable
> [ 0.000000] BIOS-e820: [mem 0x0000000100000000-0x0000000705ffffff] usable
>
>
> On 07/10/2014 09:50 AM, Andrey Ryabinin wrote:>> Anyways, the machine won't boot with more than 1GB of RAM, is there a solution to
>>> > get KASAN running on my machine?
>>> >
>> It's not boot with the same Failed to allocate error?
>
> I think I misunderstood your question here. With >1GB is triggers a panic() when
> KASAN fails the memblock allocation. With <=1GB it fails a bit later in boot just
> because 1GB isn't enough to load everything - so it fails in some other random
> spot as it runs on out memory.
>
>
> Thanks,
> Sasha

Looks like I found where is a problem. memblock_alloc cannot allocate
accross numa nodes,
therefore kasan fails for numa=fake>=8.
You should succeed with numa=fake=7 or less.


--
Best regards,
Andrey Ryabinin
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