Description:
Hey! During a regular image update in our upstream systemd CI, the ASan+UBSan job started complaining about a possible memory leak when running `getent ahostsv4 -s mymachines ...`. After some digging I can reproduce it even without systemd involvement:

# LD_PRELOAD=/usr/lib64/libasan.so.8 getent ahostsv4 localhost
127.0.0.1 STREAM localhost
127.0.0.1 DGRAM
127.0.0.1 RAW

=================================================================
==179818==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 10 byte(s) in 1 object(s) allocated from:
#0 0x7f15ebee1359 in __interceptor_malloc /usr/src/debug/gcc/gcc/libsanitizer/asan/asan_malloc_linux.cpp:69
#1 0x7f15ebcc13de in __strdup (/usr/lib/libc.so.6+0xa33de) (BuildId: 023ea16fd6c04ef9cf094507024e6ecdb35e02ca)
#2 0x7f15eabf0073 (<unknown module>)

SUMMARY: AddressSanitizer: 10 byte(s) leaked in 1 allocation(s).

This is reproducible only with glibc 2.38-4. With glibc 2.38-3 everything seems to work as expected:

# LD_PRELOAD=/usr/lib64/libasan.so.8 getent ahostsv4 localhost
127.0.0.1 STREAM localhost
127.0.0.1 DGRAM
127.0.0.1 RAW

Since the stack trace is not complete, I can't tell for sure if it's an actual issue or not, but it's definitely something new that was introduced in 2.38-4.

Additional info:
* package version(s)
glibc 2.38-4