Be aware of AddressSanitizer’s shadow memory usage

The following is excerpted from AddressSanitizerAlgorithm:

AddressSanitizer maps 8 bytes of the application memory into 1 byte of the shadow memory.

It means if you use ASAN_POISON_MEMORY_REGION/ASAN_UNPOISON_MEMORY_REGION (please refer AddressSanitizerManualPoisoning), you should take shadow memory usage into account if application memory is huge. E.g., my application occupies ~216 GiB, the shadow memory will occupy about 216 / 8 = 27 GiB.

Fix “cannot find libasan_preinit.o” issue in Void Linux

In my Void Linux, using clang with -fsanitize=address option is OK:

$ clang -std=c11 -fsanitize=address test.c
$

Whilst gcc reports following error:

$ gcc -std=c11 -fsanitize=address test.c
/usr/bin/ld: cannot find libasan_preinit.o: No such file or directory
/usr/bin/ld: cannot find -lasan
collect2: error: ld returned 1 exit status

The solution is to install libsanitizer-devel:

$ sudo xbps-install -Su libsanitizer-devel
$ gcc -std=c11 -fsanitize=address test.c
$

Check the linked libraries of executalbe file:

$ ldd a.out
    linux-vdso.so.1 (0x00007fff1a58b000)
    libasan.so.5 => /usr/lib/libasan.so.5 (0x00007fc1f0f02000)
    libc.so.6 => /usr/lib/libc.so.6 (0x00007fc1f0d3f000)
    libdl.so.2 => /usr/lib/../lib/libdl.so.2 (0x00007fc1f0d3a000)
    librt.so.1 => /usr/lib/../lib/librt.so.1 (0x00007fc1f0d2f000)
    libpthread.so.0 => /usr/lib/../lib/libpthread.so.0 (0x00007fc1f0d0e000)
    libstdc++.so.6 => /usr/lib/../lib/libstdc++.so.6 (0x00007fc1f0a99000)
    libm.so.6 => /usr/lib/../lib/libm.so.6 (0x00007fc1f0952000)
    libgcc_s.so.1 => /usr/lib/../lib/libgcc_s.so.1 (0x00007fc1f0938000)
    /lib/ld-linux-x86-64.so.2 (0x00007fc1f193d000)

Reference:
How to use gcc with sanitizers in Void Linux?.