# Tcmalloc error in device that does not has 48 bit virtual address space size **URL:** \ **Category:** Mojo\ **Created:** [September 20, 2026, 3:02am UTC](https://forum.modular.com/t/tcmalloc-error-in-device-that-does-not-has-48-bit-virtual-address-space-size/3514 "2026-09-20T03:02:37Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Fuji](https://avatars.discourse-cdn.com/v4/letter/f/a9a28c/32.png) [@Fuji](https://forum.modular.com/u/Fuji)\ **Post date:** [September 20, 2026, 3:02am UTC](https://forum.modular.com/t/tcmalloc-error-in-device-that-does-not-has-48-bit-virtual-address-space-size/3514/1 "2026-09-20T03:02:38Z")
Hello, I get this error in Mojo after fresh install [dev@localhost ~]# uv init mojo\_tes Initialized project `mojo-tes` at `/dev/mojo_tes` [dev@localhost ~]# cd mojo\_tes [dev@localhost mojo\_tes]# uv run python --version Using CPython 3.12.14 Creating virtual environment at: .venv Built mojo-tes @ file:///dev/mojo\_tes Installed 1 package in 137ms Python 3.12.14 [dev@localhost mojo\_tes]# uv add mojo Using CPython 3.12.14 Removed virtual environment at: .venv Creating virtual environment at: .venv Resolved 10 packages in 1.79s Built mojo-tes @ file:///dev/mojo\_tes Prepared 10 packages in 2m 22s Installed 10 packages in 3.23s + click==8.5.0 + mblack==26.6.0 + mojo==1.1.0 + mojo-compiler==1.1.0 + mojo-compiler-mojo-libs==1.1.0 + mojo-lldb-libs==1.1.0 + mojo-tes==0.1.0 (from file:///dev/mojo\_tes) + mypy-extensions==1.1.0 + pathspec==1.1.1 + platformdirs==4.11.11 [dev@localhost mojo\_tes]# uv run mojo Using CPython 3.12.14 Removed virtual environment at: .venv Creating virtual environment at: .venv Installed 10 packages in 255ms /dev/mojo\_tes/.venv/bin/mojo: error while loading shared libraries: libMSupportGlobals.so: cannot open shared object file: No such file or directory [dev@localhost mojo\_tes]# find /dev/mojo\_tes/.venv -name ‘libMSupportGlobals.so’ 2\>/dev/null /dev/mojo\_tes/.venv/lib/python3.12/site-packages/modular/lib/libMSupportGlobals.so [dev@localhost mojo\_tes]# find /dev/mojo\_tes/.venv -name ‘libMSupportGlobals.so’ 2\>/dev/null /dev/mojo\_tes/.venv/lib/python3.12/site-packages/modular/lib/libMSupportGlobals.so [dev@localhost mojo\_tes]# export LD\_LIBRARY\_PATH=/dev/mojo\_tes/.venv/lib/python3.12/site-packages/modular/lib:$LD\_LIBRARY\_PATH [dev@localhost mojo\_tes]# uv run mojo Using CPython 3.12.14 Removed virtual environment at: .venv Creating virtual environment at: .venv Installed 10 packages in 603ms 26653 external/tcmalloc+/tcmalloc/internal/system\_allocator.h:585] MmapAligned() failed - unable to allocate with tag (hint=0x4e9e40000000, size=1073741824, alignment=1073741824) - is something limiting address placement? 26653 external/tcmalloc+/tcmalloc/internal/system\_allocator.h:592] Note: the allocation may have failed because TCMalloc assumes a 48-bit virtual address space size; you may need to rebuild TCMalloc with TCMALLOC\_ADDRESS\_BITS defined to your system’s virtual address space size 26653 external/tcmalloc+/tcmalloc/arena.cc:59] CHECK in Alloc: FATAL ERROR: Out of memory trying to allocate internal tcmalloc data (bytes=131072, object-size=16384); is something preventing mmap from succeeding (sandbox, VSS limitations)? How to fix it? Thank you ---
**Author:** ![Ehsan](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/ehsan/32/142_2.png) [@Ehsan](https://forum.modular.com/u/Ehsan)\ **Post date:** [September 20, 2026, 3:09am UTC](https://forum.modular.com/t/tcmalloc-error-in-device-that-does-not-has-48-bit-virtual-address-space-size/3514/2 "2026-09-20T03:09:12Z")
Please check the [system requirements](https://mojolang.org/docs/requirements/). ---
**Author:** ![Fuji](https://avatars.discourse-cdn.com/v4/letter/f/a9a28c/32.png) [@Fuji](https://forum.modular.com/u/Fuji)\ **Post date:** [September 20, 2026, 3:25am UTC](https://forum.modular.com/t/tcmalloc-error-in-device-that-does-not-has-48-bit-virtual-address-space-size/3514/3 "2026-09-20T03:25:48Z")
Thank you for the response, my system should able to run it. The origin of the error is not from Mojo, but Tcmalloc. I encountered exact same error message from Tcmalloc in another project in the past. It seems that Tcmalloc is not portable, is there a way to change it to a more portable allocator like Mimalloc?