ich hab erstmal wieder die version 5.5.4-1 drauf, also kein stress. nur vll. hilft das backtrace jemanden der sich damit auskennt.

*** glibc detected *** dhcpcd: double free or corruption (fasttop): 0x091669d8 ***
======= Backtrace: =========
/lib/libc.so.6(+0x73842)[0xb7670842]
dhcpcd[0x8054a54]
dhcpcd[0x8056395]
dhcpcd[0x8051000]
dhcpcd[0x80525b9]
dhcpcd[0x804a005]
/lib/libc.so.6(__libc_start_main+0xf3)[0xb7616483]
dhcpcd[0x804a501]
======= Memory map: ========
08048000-08061000 r-xp 00000000 fe:01 918644 /sbin/dhcpcd
08061000-08062000 r--p 00018000 fe:01 918644 /sbin/dhcpcd
08062000-08063000 rw-p 00019000 fe:01 918644 /sbin/dhcpcd
08063000-08064000 rw-p 00000000 00:00 0
09163000-09185000 rw-p 00000000 00:00 0 [heap]
b75b2000-b75ce000 r-xp 00000000 fe:01 789029 /usr/lib/libgcc_s.so.1
b75ce000-b75cf000 rw-p 0001b000 fe:01 789029 /usr/lib/libgcc_s.so.1
b75e0000-b75e2000 rw-p 00000000 00:00 0
b75e2000-b75f9000 r-xp 00000000 fe:01 917524 /lib/libpthread-2.15.so
b75f9000-b75fa000 r--p 00016000 fe:01 917524 /lib/libpthread-2.15.so
b75fa000-b75fb000 rw-p 00017000 fe:01 917524 /lib/libpthread-2.15.so
b75fb000-b75fd000 rw-p 00000000 00:00 0
b75fd000-b7799000 r-xp 00000000 fe:01 918652 /lib/libc-2.15.so
b7799000-b779b000 r--p 0019c000 fe:01 918652 /lib/libc-2.15.so
b779b000-b779c000 rw-p 0019e000 fe:01 918652 /lib/libc-2.15.so
b779c000-b779f000 rw-p 00000000 00:00 0
b779f000-b77a6000 r-xp 00000000 fe:01 917529 /lib/librt-2.15.so
b77a6000-b77a7000 r--p 00006000 fe:01 917529 /lib/librt-2.15.so
b77a7000-b77a8000 rw-p 00007000 fe:01 917529 /lib/librt-2.15.so
b77b8000-b77ba000 rw-p 00000000 00:00 0
b77ba000-b77bb000 r-xp 00000000 00:00 0 [vdso]
b77bb000-b77db000 r-xp 00000000 fe:01 921992 /lib/ld-2.15.so
b77db000-b77dc000 r--p 0001f000 fe:01 921992 /lib/ld-2.15.so
b77dc000-b77dd000 rw-p 00020000 fe:01 921992 /lib/ld-2.15.so
bff70000-bff91000 rw-p 00000000 00:00 0 [stack]

Lg VanHaze
Google meint dass folgendes vor dem dhcpcd Aufruf hilft: 
export MALLOC_CHECK_=0
da bei neueren Versionen der glibc ein doppelter Aufruf von free() nicht mehr toleriert wird:
http://www.linuxquestions.org/questions/linux-newbie-8/dhcpd-double-free-or-corruption-732331/ schriebRecent versions of Linux libc (later than 5.4.23) and GNU libc (2.x) include a malloc implementation which is tunable via environment variables. When MALLOC_CHECK_ is set, a special (less efficient) implementation is used which is designed to be tolerant against simple errors, such as double calls of free() with the same argument, or overruns of a single byte (off-by-one bugs). Not all such errors can be protected against, however, and memory leaks can result. If MALLOC_CHECK_ is set to 0, any detected heap corruption is silently ignored and an error message is not generated; if set to 1, the error message is printed on stderr, but the program is not aborted; if set to 2, abort() is called immediately, but the error message is not generated; if set to 3, the error message is printed on stderr and program is aborted. This can be useful because otherwise a crash may happen much later, and the true cause for the problem is then very hard to track down.
Und es gibt schon nen Bugreport: https://bugs.archlinux.org/task/29200