Segmentation fault on info level logging

[Aufar Gilbran]

Hello,

I'm trying to run hello on the test directory with mallocwatch.so and info level logging. It gave me segmentation fault.

$ LD_PRELOAD=x86_64-pc-linux-gnu/mallocwatch.so PREENY_INFO=1 tests/hello
[1]    6269 segmentation fault (core dumped)  LD_PRELOAD=x86_64-pc-linux-gnu/mallocwatch.so PREENY_INFO=1 tests/hello

But running without PREENY_INFO=1 results in successful execution.

$ LD_PRELOAD=x86_64-pc-linux-gnu/mallocwatch.so tests/hello 
Hello world!

After some code modification on mallocwatch.c and logging.c, I found that it's because it segfaults because it tries to call vprintf and printf from libc. Removing the vprintf and printf from preeny_info works (without logging too). I'm not sure why though.

$ gcc -v
gcc (GCC) 8.2.1 20180831
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ ldd --version
ldd (GNU libc) 2.28
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Written by Roland McGrath and Ulrich Drepper.