Hi Konstantin/Renato
Remaining failures were due to the way compiler (LLVM) generates code
for accessing shadow memory.
It optimizes the code by Oring shadow offset instead of adding it
thinking that shadow offset is at 1/8 of address space.
On 42 bit VA, default value of 1<<36 is not at 1/8 of address space.
I changed it to
// OR-ing shadow offset if more efficient (at least on x86) if the offset
// is a power of two, but on ppc64 we have to use add since the shadow
// offset is not necessary 1/8-th of the address space.
Mapping.OrShadowOffset = !IsAArch64 && !IsPPC64
&& !(Mapping.Offset & (Mapping.Offset - 1));
Now
Failing Tests (1):
AddressSanitizer-aarch64-linux :: TestCases/throw_invoke_test.cc
Expected Passes : 414
Expected Failures : 6
Unsupported Tests : 129
Unexpected Failures: 1
Failure is due to missing stdc++, I dont have root permission on that machine.
/usr/bin/ld: cannot find -lstdc++
clang-3.7: error: linker command failed with exit code 1 (use -v to
see invocation)
regards,
Venkat.
On 30 March 2015 at 17:23, Venkataramanan Kumar
<[email protected]> wrote:
> Hi Konstantin,
>
> On 26 March 2015 at 18:10, Venkataramanan Kumar
> <[email protected]> wrote:
>> Hi Konstantin,
>>
>> On 26 March 2015 at 03:01, Konstantin Serebryany
>> <[email protected]> wrote:
>>> On Wed, Mar 25, 2015 at 10:23 AM, Venkataramanan Kumar
>>> <[email protected]> wrote:
>>>> Hi Konstantin/Renato,
>>>>
>>>>>> The values that define the location of the shadow are initialized at
>>>>>> startup,
>>>>>> so it should not be a problem.
>>>>>
>>>>> Excellent!
>>>>>
>>>>
>>>> The Shadow offset, I need to set "1<<39" for Aarch64 (42 bit VA) and
>>>> 1<<36 for Aarch64 (39 bit VA).
>>>>
>>>> In asan_mapping.h, it is defined as static const u64
>>>> kAArch64_ShadowOffset64 = 1ULL << 36.
>>>
>>>
>>> Why 1ULL << 36 or some other smaller value will not work for both?
>>>
>>
>> On 42 bit VA, I was trying to use 64 bit allocator.
>>
>> I have to fix the allocator start and size to 0x10000000000. Other
>> wise I got the below an assert failures.
>>
>> COMPILER_CHECK(kSpaceBeg % kSpaceSize == 0)
>> COMPILER_CHECK((kRegionSize) >= (1ULL << (SANITIZER_WORDSIZE / 2)))
>>
>> Putting shadow offset at 2^39 I got HighMemBeg starting at
>> 0x10000000000 which also will not interfere with application,
>> libraries and the stack.
>>
>>
>>>>
>>>> If I understand correctly, I need to initialize this at startup in
>>>> both places, compiler-rt/lib/asan and LLVM 's instrumentation place
>>>> lib/Transforms/Instrumentation/AddressSanitizer.cpp ?
>>>>
>>>>>> The values for Allocator64 have to be compile-time constants for
>>>>>> better performance,
>>>>>> but Allocator64 is not going to work on 39 (and probably on 42) bits
>>>>>> anyway.
>>>>>> We'll need to use Allocator32.
>>>>
>>>> For Aarch64 with 42 VA bit I need to turn on Allocator64
>>> Why?
>>
>> ASAN tests passed with 64 bit allocator and with changes I mentioned above.
>>
>> So I was assuming we can switch 64 bit allocators when we detect 42
>> bit VA. But I agree, as we discussed it is not a good thing to do. It
>> should be uniform across all VA and hence 32 bit allocators should be
>> default.
>>
>>>
>>>> and for 39
>>>> bit VA I need to turn on Allocator32.
>>>> ASAN/TSAN does not work when allocator32 is on for 42bit VA.
>>>
>>> Let's not mix asan and tsan.
>>> What's wrong with asan when "allocator32 is on for 42bit VA"?
>>
>> On 42 bit VA, running a simple stack resuse test case. I got this
>> assert failure.
>>
>> ==24573==AddressSanitizer CHECK failed:
>> /home/venkataramanan.kumar/LLVM/TSAN_port/Source/projects/compiler-rt/lib/sanitizer_common/sanitizer_allocator.h:841
>> "((res)) < ((kNumPossibleRegions))" (0x3ffb56, 0x80000)
>>
>> I am looking it into now,
>
> The "kNumPossibleRegions" is defined as per 39 bit VA machine (juno)
> as 0x8000000000 (max 39 bit VA) / (2^20) = 0x80000.
>
> On 42 bit I get stack memory reference at 0x3ffb5600000. The region id
> computation for the memory is 0x3ffb5600000/(2^20) is "0x3ffb56"
>
> Hence the check "((res)) < ((kNumPossibleRegions))" fails.
>
> I have to change the SANITIZER_MMAP_RANGE_SIZE to 1 <<42.
>
> 0x40000000000 (max 42 bit VA) / (2^20) = 0x3FFFFF
>
> Now I still find 76 cases still failing and looking at them.
>
>
>>
>>
>>>>
>>>> So I also need to detect and switch allocator types based on VA.
>>>>
>>>>
>>>> On 25 March 2015 at 22:21, Renato Golin <[email protected]> wrote:
>>>>> On 25 March 2015 at 16:41, Konstantin Serebryany
>>>>> <[email protected]> wrote:
>>>>>> Is it only 39 and 42, or is there a 3-rd option?
>>>>>
>>>>> As far as I know, only these two.
>>>>>
>>>>>
>>>>>> The values that define the location of the shadow are initialized at
>>>>>> startup,
>>>>>> so it should not be a problem.
>>>>>
>>>>> Excellent!
>>>>>
>>>>>
>>>>>> The values for Allocator64 have to be compile-time constants for
>>>>>> better performance,
>>>>>> but Allocator64 is not going to work on 39 (and probably on 42) bits
>>>>>> anyway.
>>>>>> We'll need to use Allocator32.
>>>>>
>>>>> That's our conclusion, too.
>>>>>
>>>>> I think the next step is to implement the run-time check for AArch64.
>>>>>
>>>>> Thanks for the help!
>>>>>
>>>>> cheers,
>>>>> --renato
>>
>> regards,
>> Venkat,
>
> regards,
> Venkat.
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