Core dump with my debugging symbols and backtrace can be found here: http://bugs.gentoo.org/show_bug.cgi?id=260089
From original Gentoo bug: http://bugs.gentoo.org/show_bug.cgi?id=260089 This was a non-reproducible crash during attach, due to failing assert: linux-nat.c:988: internal-error: linux_nat_attach: Assertion `pid == GET_PID (inferior_ptid) && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP' failed.\nA problem internal to GDB has been detected while executing attach. It is very likely duplicate of the assertion seen here: http://sourceware.org/bugzilla/show_bug.cgi?id=10757#c8 and fixed here: 2009-10-15 Paul Pluzhnikov <ppluzhnikov@google.com> PR gdb/10757 * linux-nat.c (linux_nat_post_attach_wait): Adjust assert. (lin_lwp_attach_lwp, linux_nat_attach): Handle disappearing LWP. *** This bug has been marked as a duplicate of 10757 ***