RecoTracker/PixelSeeding: array subscript ... is above array bounds in Alpaka/FlexiStorage

[iarspider]

In all IBs, GCC emits the following warnings:

>> Building alpaka/serial edm plugin tmp/el8_amd64_gcc12/src/RecoTracker/PixelSeeding/plugins/RecoTrackerPixelSeedingPortableSerialSync/libRecoTrackerPixelSeedingPortableSerialSync.so
(... gcc invocation ...)
In member function 'operator[]',
    inlined from 'size' at src/HeterogeneousCore/AlpakaInterface/interface/OneToManyAssoc.h:144:55,
    inlined from 'operator()' at src/RecoTracker/PixelSeeding/plugins/alpaka/CAHitNtupletGeneratorKernelsImpl.h:553:42,
    inlined from '__invoke_impl' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/gcc/12.3.1-40d504be6370b5a30e3947a6e575ca28/include/c++/12.3.1/bits/invoke.h:61:36,
    inlined from '__invoke' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/gcc/12.3.1-40d504be6370b5a30e3947a6e575ca28/include/c++/12.3.1/bits/invoke.h:96:40,
    inlined from '__apply_impl' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/gcc/12.3.1-40d504be6370b5a30e3947a6e575ca28/include/c++/12.3.1/tuple:1852:27,
    inlined from 'apply' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/gcc/12.3.1-40d504be6370b5a30e3947a6e575ca28/include/c++/12.3.1/tuple:1863:31,
    inlined from 'operator()' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/kernel/TaskKernelCpuSerial.hpp:92:31,
    inlined from 'ndLoopImpl' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/meta/NdLoop.hpp:25:14,
    inlined from 'ndLoopImpl' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/meta/NdLoop.hpp:44:27,
    inlined from 'ndLoop' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/meta/NdLoop.hpp:71:27,
    inlined from 'ndLoopIncIdx' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/meta/NdLoop.hpp:83:15,
    inlined from 'operator()' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/kernel/TaskKernelCpuSerial.hpp:86:31:
  src/HeterogeneousCore/AlpakaInterface/interface/FlexiStorage.h:15:60: warning: array subscript 262145 is above array bounds of 'const unsigned int[262145]' [-Warray-bounds]
    15 |     constexpr const I& operator[](int i) const { return m_v[i]; }
      |                                                            ^
src/HeterogeneousCore/AlpakaInterface/interface/FlexiStorage.h: In member function 'operator()':
src/HeterogeneousCore/AlpakaInterface/interface/FlexiStorage.h:21:7: note: while referencing 'm_v'
   21 |     I m_v[S];
      |       ^
In member function 'operator[]',
    inlined from 'size' at src/HeterogeneousCore/AlpakaInterface/interface/OneToManyAssoc.h:144:55,
    inlined from 'operator()' at src/RecoTracker/PixelSeeding/plugins/alpaka/CAHitNtupletGeneratorKernelsImpl.h:553:42,
    inlined from '__invoke_impl' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/gcc/12.3.1-40d504be6370b5a30e3947a6e575ca28/include/c++/12.3.1/bits/invoke.h:61:36,
    inlined from '__invoke' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/gcc/12.3.1-40d504be6370b5a30e3947a6e575ca28/include/c++/12.3.1/bits/invoke.h:96:40,
    inlined from '__apply_impl' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/gcc/12.3.1-40d504be6370b5a30e3947a6e575ca28/include/c++/12.3.1/tuple:1852:27,
    inlined from 'apply' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/gcc/12.3.1-40d504be6370b5a30e3947a6e575ca28/include/c++/12.3.1/tuple:1863:31,
    inlined from 'operator()' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/kernel/TaskKernelCpuSerial.hpp:92:31,
    inlined from 'ndLoopImpl' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/meta/NdLoop.hpp:25:14,
    inlined from 'ndLoopImpl' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/meta/NdLoop.hpp:44:27,
    inlined from 'ndLoop' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/meta/NdLoop.hpp:71:27,
    inlined from 'ndLoopIncIdx' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/meta/NdLoop.hpp:83:15,
    inlined from 'operator()' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/kernel/TaskKernelCpuSerial.hpp:86:31:
  src/HeterogeneousCore/AlpakaInterface/interface/FlexiStorage.h:15:60: warning: array subscript 262145 is above array bounds of 'const unsigned int[262145]' [-Warray-bounds]
    15 |     constexpr const I& operator[](int i) const { return m_v[i]; }
      |                                                            ^
src/HeterogeneousCore/AlpakaInterface/interface/FlexiStorage.h: In member function 'operator()':
src/HeterogeneousCore/AlpakaInterface/interface/FlexiStorage.h:21:7: note: while referencing 'm_v'
   21 |     I m_v[S];
      |       ^
In member function 'operator[]',
    inlined from 'size' at src/HeterogeneousCore/AlpakaInterface/interface/OneToManyAssoc.h:144:55,
    inlined from 'operator()' at src/RecoTracker/PixelSeeding/plugins/alpaka/CAHitNtupletGeneratorKernelsImpl.h:553:42,
    inlined from '__invoke_impl' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/gcc/12.3.1-40d504be6370b5a30e3947a6e575ca28/include/c++/12.3.1/bits/invoke.h:61:36,
    inlined from '__invoke' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/gcc/12.3.1-40d504be6370b5a30e3947a6e575ca28/include/c++/12.3.1/bits/invoke.h:96:40,
    inlined from '__apply_impl' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/gcc/12.3.1-40d504be6370b5a30e3947a6e575ca28/include/c++/12.3.1/tuple:1852:27,
    inlined from 'apply' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/gcc/12.3.1-40d504be6370b5a30e3947a6e575ca28/include/c++/12.3.1/tuple:1863:31,
    inlined from 'operator()' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/kernel/TaskKernelCpuSerial.hpp:92:31,
    inlined from 'ndLoopImpl' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/meta/NdLoop.hpp:25:14,
    inlined from 'ndLoopImpl' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/meta/NdLoop.hpp:44:27,
    inlined from 'ndLoop' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/meta/NdLoop.hpp:71:27,
    inlined from 'ndLoopIncIdx' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/meta/NdLoop.hpp:83:15,
    inlined from 'operator()' at /data/cmsbld/jenkins/workspace/build-any-ib/w/el8_amd64_gcc12/external/alpaka/1.1.0-0a6641b4bfdf883c8da5b9e8620be504/include/alpaka/kernel/TaskKernelCpuSerial.hpp:86:31:
  src/HeterogeneousCore/AlpakaInterface/interface/FlexiStorage.h:15:60: warning: array subscript 32769 is above array bounds of 'const unsigned int[32769]' [-Warray-bounds]
    15 |     constexpr const I& operator[](int i) const { return m_v[i]; }
      |                                                            ^
src/HeterogeneousCore/AlpakaInterface/interface/FlexiStorage.h: In member function 'operator()':
src/HeterogeneousCore/AlpakaInterface/interface/FlexiStorage.h:21:7: note: while referencing 'm_v'
   21 |     I m_v[S];
      |       ^

[cmsbuild]

cms-bot internal usage

[cmsbuild]

A new Issue was created by @iarspider.

@antoniovilela, @smuzaffar, @makortel, @rappoccio, @sextonkennedy, @Dr15Jones can you please review it and eventually sign/assign? Thanks.

cms-bot commands are listed here

[iarspider]

assign HeterogeneousCore/AlpakaInterface,RecoTracker/PixelSeeding

[cmsbuild]

New categories assigned: heterogeneous,reconstruction

@fwyzard,@jfernan2,@makortel,@mandrenguyen you have been requested to review this Pull request/Issue and eventually sign? Thanks

[iarspider]

First occurrence in CMSSW_14_1_X_2024-06-05-2300

[slava77]

@AdrianoDee
in case you haven't received this already

[Dr15Jones]

This is probably not a real issue. [I think I was wrong initially]

cmssw/RecoTracker/PixelSeeding/plugins/alpaka/CAHitNtupletGeneratorKernelsImpl.h

Lines 552 to 553 in 64d4f3b

	for (auto idx : cms::alpakatools::uniform_elements(acc, tracks_view.hitIndices().nOnes())) {
	if (tracks_view.hitIndices().size(idx) == 0)

with the final line calls

cmssw/HeterogeneousCore/AlpakaInterface/interface/OneToManyAssoc.h

Line 144 in 64d4f3b

constexpr auto size(uint32_t b) const { return off[b + 1] - off[b]; }

notice the b+1. The documentation for uniform_elements has

cmssw/HeterogeneousCore/AlpakaInterface/interface/workdivision.h

Lines 254 to 255 in 64d4f3b

	* `uniform_elements(acc [, first], extent)` returns a one-dimensional iteratable range that spans the element indices
	* from `first` (inclusive) to `extent` (exlusive).

so the b+1 will be the size of the container so off[b+1] at first glance seems to be off the end of the container.

However, looking at the definition of nOnes()

cmssw/HeterogeneousCore/CUDAUtilities/interface/OneToManyAssoc.h

Line 167 in 64d4f3b

constexpr auto nOnes() const { return totOnes() - 1; }

and

cmssw/HeterogeneousCore/CUDAUtilities/interface/OneToManyAssoc.h

Line 166 in 64d4f3b

constexpr auto totOnes() const { return off.capacity(); }

then assuming capacity is the true size of the container, than off[b+1] for the end condition should be off[ (nOnes()-1) +1] ==off[( (totOnes()-1)-1 ) +1 ] == off[totOnes() -1]

[fwyzard]

@Dr15Jones thanks for looking into this issue 👍🏻

[VinInn]

yep. All that was indeed intentional (at least in the CUDA version).