According to Oracle's Multithreaded Programming Guide, fork() should be safe-to-use inside signal handlers. But my process got stuck inside signal handler with to following back trace:
#0 __lll_lock_wait_private () at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:95
#1 0x00007f86e6a9990d in _L_lock_48 () from /lib/x86_64-linux- gnu/libc.so.6
#2 0x00007f86e6a922ec in ptmalloc_lock_all () at arena.c:242
#3 0x00007f86e6ad5e82 in __libc_fork () at ./nptl/sysdeps/unix/sysv/linux/x86_64/../fork.c:95
#4 0x00007f86e7d9f125 in __fork () at ./nptl/sysdeps/unix/sysv/linux/pt-fork.c:25
....
#7 signal handler called
So as malloc is not safe to be use in signal handler how fork can be?
Thanks in advance.
This is now listed as a bug by RedHat:
Bug 1422161 - glibc: fork is not async-signal-safe
...
+++ This bug was initially created as a clone of Bug #1422159 +++
POSIX requires that fork is async-signal-safe. Our current implementation is not.