It seems somewhat easy to crash qemu with slirp if we queue multiple packets. I didn't investigate further yet so I don't know if this is a regression. Anyone knowledgeable about slirp wants to take a look?
/home/mst/qemu-test/bin/qemu-system-x86_64 -enable-kvm -m 1G -drive file=/home/mst/rhel6.qcow2 -netdev user,id=bar -net nic,netdev=bar,model=e1000,macaddr=52:54:00:12:34:57 -redir tcp:8022::22 -vnc :1 -monitor stdio While guest is booting, quickly do this ssh localhost -p 8022 CTRL-C ssh localhost -p 8022 CTRL-C ssh localhost -p 8022 CTRL-C ssh localhost -p 8022 CTRL-C When guest triest to bring up link, qemu crashes: Program received signal SIGSEGV, Segmentation fault. 0x00007ffff7e4f8a7 in slirp_insque (a=0x0, b=0x7ffff91681f0) at slirp/misc.c:27 27 element->qh_link = head->qh_link; (gdb) where #0 0x00007ffff7e4f8a7 in slirp_insque (a=0x0, b=0x7ffff91681f0) at slirp/misc.c:27 #1 0x00007ffff7e4ddd8 in if_start (slirp=0x7ffff8b0e4f0) at slirp/if.c:194 #2 0x00007ffff7e51290 in slirp_select_poll (readfds=0x7fffffffdfe0, writefds= 0x7fffffffdf60, xfds=0x7fffffffdee0, select_error=0) at slirp/slirp.c:588 #3 0x00007ffff7e114c3 in main_loop_wait (nonblocking=<value optimized out>) at main-loop.c:466 #4 0x00007ffff7e09ed4 in main_loop (argc=<value optimized out>, argv=<value optimized out>, envp=<value optimized out>) at /home/mst/scm/qemu/vl.c:1482 #5 main (argc=<value optimized out>, argv=<value optimized out>, envp=<value optimized out>) at /home/mst/scm/qemu/vl.c:3525 (gdb) p element $1 = (struct quehead *) 0x0 -- MST