bisecting fixing commit since 12cd844a39ed16aa183a820a54fe6f9a0bb4cd14
building syzkaller on 749688d22abef3f3cb9a0480e15c19a3f2ed8e13
testing commit 12cd844a39ed16aa183a820a54fe6f9a0bb4cd14
compiler: gcc version 8.4.1 20210217 (GCC)
kernel signature: f64157de8c65c3478fd1b6f8e3375ee761de7050194580fb5dc9a4884941fd88
all runs: crashed: WARNING in ipvlan_unregister_nf_hook
testing current HEAD c01d4d1b885d96a7c8c27d629abeb918ca897dbe
testing commit c01d4d1b885d96a7c8c27d629abeb918ca897dbe
compiler: gcc version 8.4.1 20210217 (GCC)
kernel signature: d9780aec8b364d5cc8f5ab873b23ec26e7d823ccb807a7372bf19bc03be30b3f
all runs: crashed: unregister_netdevice: waiting for DEV to become free
revisions tested: 2, total time: 29m54.076682583s (build: 21m47.378184761s, test: 6m39.246673218s)
the crash still happens on HEAD
commit msg: Linux 4.14.257
crash: unregister_netdevice: waiting for DEV to become free
unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1