[llvm-dev] ASan port for Myriad RTEMS

[Kostya Serebryany via llvm-dev]

On RAM...

You chose the 32-byte shadow granularity to reduce the RAM overhead,
but I am afraid this will actually increase it due to extra alignment
requirements,
especially if an average allocation on your typical application is small.

The pointers are 32-bit, right?
Given how RAM-constrained your environment is, maybe you should consider
something more like HWASAN instead of ASAN.
https://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html
But you may not have enough address bits. :(

--kcc



On Fri, May 4, 2018 at 3:10 PM Kostya Serebryany <kcc at google.com> wrote:

> Hi Walter,
>
> I've done a first quick scan.
> Overall looks reasonable, but I'd like to try reducing the number of newly
> introduced platform-specific ifs.
>
> Vitaly, please also take a look (once my initial comments are addressed).
>
> One outstanding issue is your problem with initialization vs checking,
> which requires you to insert so many ifs.
> Is there any chance you can avoid this?
> If you control the OS, surely you can do at least minimal initialization
> of the shadow at a proper moment...
>
> --kcc
>
> On Fri, May 4, 2018 at 2:00 PM Walter Lee via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> I have ported ASan in LLVM to Myriad RTEMS, and I would like to
>> upstream the port.  Below is the design doc.  Feedback welcome.
>>
>>
>> https://docs.google.com/document/d/1oxmk0xUojybDaQDAuTEVpHVMi5xQX74cJPyMJbaSaRM
>>
>> The port is expected to work with modified versions of RTEMS and
>> newlib.  I have a git repo with changes to those projects, that I can
>> make available if there is interest.
>>
>> Here is the patch series:
>> https://reviews.llvm.org/D46451 [asan] Add instrumentation support for
>> Myriad
>> https://reviews.llvm.org/D46452 [sanitizer] Don't add --export-dynamic
>> for
>> Myriad
>> https://reviews.llvm.org/D46453 [sanitizer] Add definitions for Myriad
>> RTEMS platform
>> https://reviews.llvm.org/D46454 [sanitizer] Trivial portion of the port
>> to
>> Myriad RTEMS
>> https://reviews.llvm.org/D46456 [asan] Add support for Myriad RTEMS
>> memory
>> map
>> https://reviews.llvm.org/D46457 [asan] Add a magic shadow value for shadw
>> gap
>> https://reviews.llvm.org/D46459 [asan] On RTEMS, checks for asan_inited
>> before entering ASan run-time
>> https://reviews.llvm.org/D46461 [asan] Set flags appropriately for RTEMS
>> https://reviews.llvm.org/D46462 [sanitizer] Allow Fuchsia symbolizer to
>> be
>> reused by Myriad RTEMS
>> https://reviews.llvm.org/D46463 [sanitizer] On RTEMS, avoid recursion
>> when
>> reporting Mmap failure
>> https://reviews.llvm.org/D46465 [asan] Port asan_malloc_linux.cc to RTEMS
>> https://reviews.llvm.org/D46466 [asan] Add AsanThread::Restart() to
>> support
>> thread restart
>> https://reviews.llvm.org/D46467 [asan] Add argument to allow fake stack
>> to
>> be initialized during thread init
>> https://reviews.llvm.org/D46468 [asan] Add target-specific files for
>> Myriad
>> RTEMS port
>> https://reviews.llvm.org/D46469 [sanitizer] Port fast stack unwinder to
>> sparcv8
>>
>> Thanks,
>>
>> Walter
>> _______________________________________________
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>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>
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