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From: "iii at linux dot ibm.com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug sanitizer/115461] lsan doesn't work on s390x
Date: Thu, 13 Jun 2024 14:57:57 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D115461

--- Comment #5 from Ilya Leoshkevich <iii at linux dot ibm.com> ---
The LLVM testsuite still passes.

Looking a bit deeper:

$ LSAN_OPTIONS=3Dverbosity=3D1,log_pointers=3D1 ./a.out
[...]
0x508000000000
=3D=3D1522380=3D=3DLeakSanitizer: checking for leaks
[...]
=3D=3D1522381=3D=3DScanning STACK range 0x03ffffffa3d8-0x03ffffffb000.
=3D=3D1522381=3D=3D0x03ffffffa820: found 0x508000000000 pointing into chunk
0x508000000000-0x50800000007b of size 123.

So something spilled the pointer value on stack, and LSan thinks that it's
still referenced. And indeed, turning stack scanning off resolves the issue:

$ LSAN_OPTIONS=3Duse_stacks=3D0 ./a.out
0x508000000000

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
=3D=3D1522412=3D=3DERROR: LeakSanitizer: detected memory leaks

Direct leak of 123 byte(s) in 1 object(s) allocated from:
    #0 0x2aa00045bbd in malloc
[...]/llvm-project/compiler-rt/lib/lsan/lsan_interceptors.cpp:75:3
    #1 0x2aa0004779d in main ([...]/llvm-project/build/a.out+0x4779d)

SUMMARY: LeakSanitizer: 123 byte(s) leaked in 1 allocation(s).=