From: aryabinin@virtuozzo•com (Andrey Ryabinin)
To: linux-arm-kernel@lists•infradead.org
Subject: KASAN issues with idle / hotplug area
Date: Thu, 18 Feb 2016 11:22:24 +0300 [thread overview]
Message-ID: <56C57F40.3050500@virtuozzo.com> (raw)
In-Reply-To: <20160217191643.GK32647@leverpostej>
On 02/17/2016 10:16 PM, Mark Rutland wrote:
> On Wed, Feb 17, 2016 at 05:56:56PM +0000, Mark Rutland wrote:
>> On Wed, Feb 17, 2016 at 05:01:11PM +0000, Mark Rutland wrote:
>>> On Wed, Feb 17, 2016 at 02:39:51PM +0000, Mark Rutland wrote:
>>>> Perhaps the simplest option is to not instrument invoke_psci_fn_* and
>>>> psci_suspend_finisher. Do we have a per-function annotation to avoid
>>>> KASAN instrumentation, like notrace? I need to investigate, but we may
>>>> also need notrace for similar reasons.
>>>
>>> I came up with the patch below, per the reasoning above.
>>>
>>> It _changes_ the KASAN splats (I see errors in tick_program_event rather
>>> than find_busiest_group), but doesn't seem to get rid of them. I'm not
>>> sure if I've missed something, or if we also have another latent issue.
>>>
>>> Ideas?
>>
>> I'd missed annotating __cpu_suspend_save. I've fixed that up locally
>> (along with s/virt_to_phys/__virt_to_phys due to the inlining issue).
>
> Thinking about it more, I shouldn't have to annotate __cpu_suspend_save,
> as it returns (and hence should have cleaned up after itself).
>
Right, we need to no-sanitize only functions that passed to 'cpu_suspend(arg, fn);'
> Looking at the assembly, functions seem to get instrumented regardless
> of the __no_sanitize_address annotation. The assembly of
> __invoke_psci_fn_{smc,hvc} look identical, even if one has the
> annotation and one does not.
>
> In the case below, it looks like __invoke_psci_fn_hvc is storing to the
> shadow area even though it's anotated with __no_sanitize_address. Note
> that the adrp symbol resolution is bogus; psci_to_linux_errno happens to
> be at offset 0 in the as-yet unlinked psci.o object.
>
...
> I also tried using __attribute__((no_sanitize_address)) directly, in
> case there was some header issue, but that doesn't seem to be the case.
>
> I'm using the Linaro 15.08 AArch64 GCC 5.1. Is anyone else able to
> confirm whether they see the same? Does the same happen for x86?
>
Confirming, this happens on every GCC I have (including x86).
It seems that 'no_sanitize_address' in gcc removes only memory access checks
but it doesn't remove stack redzones.
I think this is wrong, e.g. clang removes instrumentation completely. I'll submit a bug.
But we need fix this in kernel.
I see two options here:
* completely disable instrumentation for drivers/firmware/psci.c
* get back to assembly implementation
> Thanks,
> Mark.
>
next prev parent reply other threads:[~2016-02-18 8:22 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-01 10:54 [PATCH v5sub1 0/8] arm64: split linear and kernel mappings Ard Biesheuvel
2016-02-01 10:54 ` [PATCH v5sub1 1/8] of/fdt: make memblock minimum physical address arch configurable Ard Biesheuvel
2016-02-01 10:54 ` [PATCH v5sub1 2/8] arm64: add support for ioremap() block mappings Ard Biesheuvel
2016-02-01 14:10 ` Mark Rutland
2016-02-01 14:56 ` Catalin Marinas
2016-02-01 10:54 ` [PATCH v5sub1 3/8] arm64: introduce KIMAGE_VADDR as the virtual base of the kernel region Ard Biesheuvel
2016-02-01 10:54 ` [PATCH v5sub1 4/8] arm64: pgtable: implement static [pte|pmd|pud]_offset variants Ard Biesheuvel
2016-02-01 10:54 ` [PATCH v5sub1 5/8] arm64: decouple early fixmap init from linear mapping Ard Biesheuvel
2016-02-01 10:54 ` [PATCH v5sub1 6/8] arm64: kvm: deal with kernel symbols outside of " Ard Biesheuvel
2016-02-01 10:54 ` [PATCH v5sub1 7/8] arm64: move kernel image to base of vmalloc area Ard Biesheuvel
2016-02-01 12:24 ` Catalin Marinas
2016-02-01 12:27 ` Ard Biesheuvel
2016-02-01 13:41 ` Catalin Marinas
2016-02-01 14:32 ` Mark Rutland
2016-02-12 14:58 ` Catalin Marinas
2016-02-12 15:02 ` Ard Biesheuvel
2016-02-12 15:10 ` Catalin Marinas
2016-02-12 15:17 ` Ard Biesheuvel
2016-02-12 15:26 ` Catalin Marinas
2016-02-12 15:38 ` Sudeep Holla
2016-02-12 16:06 ` Catalin Marinas
2016-02-12 16:44 ` Ard Biesheuvel
2016-02-15 14:28 ` Andrey Ryabinin
2016-02-15 14:35 ` Mark Rutland
2016-02-15 18:59 ` Catalin Marinas
2016-02-16 12:59 ` Andrey Ryabinin
2016-02-16 14:12 ` Mark Rutland
2016-02-16 14:29 ` Mark Rutland
2016-02-16 15:17 ` Ard Biesheuvel
2016-02-16 15:36 ` Andrey Ryabinin
2016-02-16 16:42 ` Mark Rutland
2016-02-17 9:15 ` Andrey Ryabinin
2016-02-17 10:10 ` James Morse
2016-02-17 10:19 ` Catalin Marinas
2016-02-17 10:36 ` Catalin Marinas
2016-02-17 10:18 ` Catalin Marinas
2016-02-17 10:48 ` Mark Rutland
2016-02-17 14:39 ` Mark Rutland
2016-02-17 16:31 ` Andrey Ryabinin
2016-02-17 19:35 ` Mark Rutland
2016-02-17 17:01 ` KASAN issues with idle / hotplug area (was: Re: [PATCH v5sub1 7/8] arm64: move kernel image to base of vmalloc area) Mark Rutland
2016-02-17 17:56 ` Mark Rutland
2016-02-17 19:16 ` Mark Rutland
2016-02-18 8:06 ` Ard Biesheuvel
2016-02-18 8:22 ` Andrey Ryabinin [this message]
2016-02-18 8:42 ` KASAN issues with idle / hotplug area Andrey Ryabinin
2016-02-18 9:38 ` Andrey Ryabinin
2016-02-18 11:34 ` Mark Rutland
2016-02-18 9:39 ` Lorenzo Pieralisi
2016-02-18 11:38 ` Mark Rutland
2016-02-18 11:45 ` Andrey Ryabinin
2016-02-18 11:15 ` Mark Rutland
2016-02-18 11:46 ` Andrey Ryabinin
2016-02-18 12:08 ` Mark Rutland
2016-02-12 17:47 ` [PATCH v5sub1 7/8] arm64: move kernel image to base of vmalloc area James Morse
2016-02-12 18:01 ` Ard Biesheuvel
2016-02-01 10:54 ` [PATCH v5sub1 8/8] arm64: allow kernel Image to be loaded anywhere in physical memory Ard Biesheuvel
2016-02-01 14:50 ` Mark Rutland
2016-02-01 16:28 ` Fu Wei
2016-02-16 8:55 ` Fu Wei
2016-02-01 15:06 ` Catalin Marinas
2016-02-01 15:13 ` Ard Biesheuvel
2016-02-01 16:31 ` Ard Biesheuvel
2016-02-01 17:31 ` Catalin Marinas
2016-02-01 17:57 ` Ard Biesheuvel
2016-02-01 18:02 ` Catalin Marinas
2016-02-01 18:30 ` [PATCH] arm64: move back to generic memblock_enforce_memory_limit() Ard Biesheuvel
2016-02-02 10:19 ` Catalin Marinas
2016-02-02 10:28 ` Ard Biesheuvel
2016-02-02 10:44 ` Catalin Marinas
2016-02-12 19:45 ` [PATCH v5sub1 0/8] arm64: split linear and kernel mappings Matthias Brugger
2016-02-12 19:47 ` Ard Biesheuvel
2016-02-12 20:10 ` Matthias Brugger
2016-02-12 20:37 ` Ard Biesheuvel
2016-02-13 14:28 ` Ard Biesheuvel
2016-02-15 13:29 ` Matthias Brugger
2016-02-15 13:40 ` Will Deacon
2016-02-15 14:58 ` Ard Biesheuvel
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