[ASan] [AArch64] Simple program crashes on startup with `mmap` failure in ASan runtime on Clang 20

[happyme531]

Description:

When compiling a minimal C++ "Hello, World!" program with -fsanitize=address on AArch64 with a recent Clang 20 development build, the resulting executable fails immediately upon execution.

The error message indicates an "out of memory" failure when the AddressSanitizer runtime attempts to mmap its shadow memory at 0x040000000000. The program crashes before main() is called, and the stack trace is empty, suggesting a failure very early in the runtime initialization process.

Environment:

• Clang Version:

  Debian clang version 20.1.7 (++20250613123054+9ba132be8eea-1~exp1~20250613003154.130)
  Target: aarch64-unknown-linux-gnu
  Thread model: posix
  InstalledDir: /usr/lib/llvm-20/bin
  

• Operating System:

lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description: Debian GNU/Linux 11 (bullseye)
Release: 11
Codename: bullseye

ulimit -a
Maximum size of core files created (kB, -c) 0
Maximum size of a process’s data segment (kB, -d) unlimited
Control of maximum nice priority (-e) 0
Maximum size of files created by the shell (kB, -f) unlimited
Maximum number of pending signals (-i) 126000
Maximum size that may be locked into memory (kB, -l) 4033516
Maximum resident set size (kB, -m) unlimited
Maximum number of open file descriptors (-n) 1048576
Maximum bytes in POSIX message queues (kB, -q) 800
Maximum realtime scheduling priority (-r) 0
Maximum stack size (kB, -s) 8192
Maximum amount of CPU time in seconds (seconds, -t) unlimited
Maximum number of processes available to current user (-u) 126000
Maximum amount of virtual memory available to each process (kB, -v) unlimited
Maximum contiguous realtime CPU time (-y) unlimited
```

• Hardware: Rockchip RK3588 development board, with 32GB RAM.

Steps to Reproduce:

1. Create the following C++ file (test.cpp):

   #include <iostream>
   
   int main() {
     std::cout << "Hello, World!" << std::endl;
     return 0;
   }

2. Compile it with Clang 20 and AddressSanitizer enabled:

   clang++-20 ./test.cpp -fsanitize=address

3. Run the resulting executable:

   ./a.out

Actual Result:

The program crashes immediately with the following error from the AddressSanitizer runtime:

==843770==ERROR: AddressSanitizer: out of memory: failed to allocate 0x2000 (8192) bytes of memory at address 0x040000000000 (error code: 12)
==843770==Process memory map follows:
        0x000ffffff000-0x001200000000
        0x001200000000-0x001400000000
        0x001400000000-0x002000000000
        0x00556ef70000-0x00556f0bf000   /tmp/a.out
        0x00556f0cf000-0x00556f0d3000   /tmp/a.out
        0x00556f0d3000-0x00556f0d6000   /tmp/a.out
        0x00556f0d6000-0x00556fa6a000
        0x007f9c200000-0x007f9c300000
        0x007f9c400000-0x007f9c500000
        0x007f9c572000-0x007f9ca00000
        0x007f9cb00000-0x007f9cc00000
        0x007f9cca3000-0x007f9ccb3000
        0x007f9ccb3000-0x007f9ce0f000   /usr/lib/aarch64-linux-gnu/libc-2.31.so
        0x007f9ce0f000-0x007f9ce1e000   /usr/lib/aarch64-linux-gnu/libc-2.31.so
        0x007f9ce1e000-0x007f9ce22000   /usr/lib/aarch64-linux-gnu/libc-2.31.so
        0x007f9ce22000-0x007f9ce24000   /usr/lib/aarch64-linux-gnu/libc-2.31.so
        0x007f9ce24000-0x007f9ce27000
        0x007f9ce27000-0x007f9ce3a000   /usr/lib/aarch64-linux-gnu/libgcc_s.so.1
        0x007f9ce3a000-0x007f9ce49000   /usr/lib/aarch64-linux-gnu/libgcc_s.so.1
        0x007f9ce49000-0x007f9ce4a000   /usr/lib/aarch64-linux-gnu/libgcc_s.so.1
        0x007f9ce4a000-0x007f9ce4b000   /usr/lib/aarch64-linux-gnu/libgcc_s.so.1
        0x007f9ce4b000-0x007f9ce5e000   /usr/lib/aarch64-linux-gnu/libresolv-2.31.so
        0x007f9ce5e000-0x007f9ce6e000   /usr/lib/aarch64-linux-gnu/libresolv-2.31.so
        0x007f9ce6e000-0x007f9ce6f000   /usr/lib/aarch64-linux-gnu/libresolv-2.31.so
        0x007f9ce6f000-0x007f9ce70000   /usr/lib/aarch64-linux-gnu/libresolv-2.31.so
        0x007f9ce70000-0x007f9ce72000
        0x007f9ce72000-0x007f9ce75000   /usr/lib/aarch64-linux-gnu/libdl-2.31.so
        0x007f9ce75000-0x007f9ce84000   /usr/lib/aarch64-linux-gnu/libdl-2.31.so
        0x007f9ce84000-0x007f9ce85000   /usr/lib/aarch64-linux-gnu/libdl-2.31.so
        0x007f9ce85000-0x007f9ce86000   /usr/lib/aarch64-linux-gnu/libdl-2.31.so
        0x007f9ce86000-0x007f9ce8d000   /usr/lib/aarch64-linux-gnu/librt-2.31.so
        0x007f9ce8d000-0x007f9ce9c000   /usr/lib/aarch64-linux-gnu/librt-2.31.so
        0x007f9ce9c000-0x007f9ce9d000   /usr/lib/aarch64-linux-gnu/librt-2.31.so
        0x007f9ce9d000-0x007f9ce9e000   /usr/lib/aarch64-linux-gnu/librt-2.31.so
        0x007f9ce9e000-0x007f9ceba000   /usr/lib/aarch64-linux-gnu/libpthread-2.31.so
        0x007f9ceba000-0x007f9cec9000   /usr/lib/aarch64-linux-gnu/libpthread-2.31.so
        0x007f9cec9000-0x007f9ceca000   /usr/lib/aarch64-linux-gnu/libpthread-2.31.so
        0x007f9ceca000-0x007f9cecb000   /usr/lib/aarch64-linux-gnu/libpthread-2.31.so
        0x007f9cecb000-0x007f9cecf000
        0x007f9cecf000-0x007f9cf68000   /usr/lib/aarch64-linux-gnu/libm-2.31.so
        0x007f9cf68000-0x007f9cf78000   /usr/lib/aarch64-linux-gnu/libm-2.31.so
        0x007f9cf78000-0x007f9cf79000   /usr/lib/aarch64-linux-gnu/libm-2.31.so
        0x007f9cf79000-0x007f9cf7a000   /usr/lib/aarch64-linux-gnu/libm-2.31.so
        0x007f9cf7a000-0x007f9d131000   /usr/lib/aarch64-linux-gnu/libstdc++.so.6.0.28
        0x007f9d131000-0x007f9d141000   /usr/lib/aarch64-linux-gnu/libstdc++.so.6.0.28
        0x007f9d141000-0x007f9d14c000   /usr/lib/aarch64-linux-gnu/libstdc++.so.6.0.28
        0x007f9d14c000-0x007f9d14f000   /usr/lib/aarch64-linux-gnu/libstdc++.so.6.0.28
        0x007f9d14f000-0x007f9d175000
        0x007f9d175000-0x007f9d196000   /usr/lib/aarch64-linux-gnu/ld-2.31.so
        0x007f9d196000-0x007f9d1a3000
        0x007f9d1a3000-0x007f9d1a5000   [vvar]
        0x007f9d1a5000-0x007f9d1a6000   [vdso]
        0x007f9d1a6000-0x007f9d1a7000   /usr/lib/aarch64-linux-gnu/ld-2.31.so
        0x007f9d1a7000-0x007f9d1a9000   /usr/lib/aarch64-linux-gnu/ld-2.31.so
        0x007fc451a000-0x007fc453b000   [stack]
==843770==End of process memory map.
AddressSanitizer: CHECK failed: sanitizer_common.cpp:61 "((0 && "unable to mmap")) != (0)" (0x0, 0x0) (tid=843770)
    <empty stack>

Expected Result:

The program should execute successfully, print "Hello, World!" to the console, and exit with status 0.

Hello, World!

Additional Notes:

Older Clang versions will also crash but with another (looks related) issue: #65144 (comment)