bisecting cause commit starting from 770fbb32d34e5d6298cc2be590c9d2fd6069aa17 building syzkaller on 78267cec1aaa5e066d66e6a6c76fea1753e51b46 testing commit 770fbb32d34e5d6298cc2be590c9d2fd6069aa17 with gcc (GCC) 8.1.0 kernel signature: 937eec0dcf7acf9361173078a626845552e651bf3a993308fc5e3d4dc84558dd run #0: crashed: KASAN: null-ptr-deref Write in kvm_put_kvm run #1: crashed: no output from test machine run #2: crashed: no output from test machine run #3: crashed: no output from test machine run #4: crashed: no output from test machine run #5: crashed: no output from test machine run #6: crashed: no output from test machine run #7: crashed: no output from test machine run #8: crashed: no output from test machine run #9: crashed: no output from test machine testing release v5.5 testing commit d5226fa6dbae0569ee43ecfc08bdcd6770fc4755 with gcc (GCC) 8.1.0 kernel signature: 7d2ba05e31d3b766ef913936c617fea5da89598edaa4868f8b378ccaee71431b all runs: crashed: no output from test machine testing release v5.4 testing commit 219d54332a09e8d8741c1e1982f5eae56099de85 with gcc (GCC) 8.1.0 kernel signature: 252d267e2fdc93f77605dc6593db74c3483623e2617d23e1eda512001fac10c9 run #0: crashed: unexpected kernel reboot run #1: crashed: unexpected kernel reboot run #2: crashed: unexpected kernel reboot run #3: crashed: unexpected kernel reboot run #4: crashed: unexpected kernel reboot run #5: crashed: unexpected kernel reboot run #6: crashed: unexpected kernel reboot run #7: crashed: unexpected kernel reboot run #8: crashed: unexpected kernel reboot run #9: crashed: no output from test machine testing release v5.3 testing commit 4d856f72c10ecb060868ed10ff1b1453943fc6c8 with gcc (GCC) 8.1.0 kernel signature: 40ad4e1b8641c7d35c07715b2c0e9c36ce200a047ab5a25ffb26af10e4ab12b2 all runs: crashed: unexpected kernel reboot testing release v5.2 testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.1.0 kernel signature: 1d5d608eac72cfd1c257a41aebe93982e8d25331e580efd1538b34d9054d0fde run #0: crashed: unexpected kernel reboot run #1: crashed: unexpected kernel reboot run #2: crashed: unexpected kernel reboot run #3: crashed: unexpected kernel reboot run #4: crashed: unexpected kernel reboot run #5: crashed: unexpected kernel reboot run #6: crashed: unexpected kernel reboot run #7: crashed: unexpected kernel reboot run #8: crashed: no output from test machine run #9: crashed: no output from test machine testing release v5.1 testing commit e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd with gcc (GCC) 8.1.0 kernel signature: 808758a4a9683e78b8dc48d598778d43bb0d81522f702137cd0ab39d7c965321 run #0: crashed: unexpected kernel reboot run #1: crashed: unexpected kernel reboot run #2: crashed: unexpected kernel reboot run #3: crashed: unexpected kernel reboot run #4: crashed: unexpected kernel reboot run #5: crashed: unexpected kernel reboot run #6: crashed: unexpected kernel reboot run #7: crashed: unexpected kernel reboot run #8: crashed: unexpected kernel reboot run #9: crashed: no output from test machine testing release v5.0 testing commit 1c163f4c7b3f621efff9b28a47abb36f7378d783 with gcc (GCC) 8.1.0 kernel signature: 808e29c87ecf35ccc1c208d9cddf56874774efec3e964f988dbdd3e072179800 run #0: crashed: unexpected kernel reboot run #1: crashed: unexpected kernel reboot run #2: crashed: unexpected kernel reboot run #3: crashed: unexpected kernel reboot run #4: crashed: unexpected kernel reboot run #5: crashed: unexpected kernel reboot run #6: crashed: unexpected kernel reboot run #7: crashed: unexpected kernel reboot run #8: crashed: no output from test machine run #9: crashed: no output from test machine testing release v4.20 testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.1.0 kernel signature: d280b189f85acf6094a8506256873e85912f026039e96bd2ce58049c39724543 run #0: crashed: unexpected kernel reboot run #1: crashed: unexpected kernel reboot run #2: crashed: unexpected kernel reboot run #3: crashed: unexpected kernel reboot run #4: crashed: unexpected kernel reboot run #5: crashed: unexpected kernel reboot run #6: crashed: unexpected kernel reboot run #7: crashed: unexpected kernel reboot run #8: crashed: unexpected kernel reboot run #9: crashed: no output from test machine testing release v4.19 testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.1.0 kernel signature: 1226e9da71868a26f2e106554c4d1085933ab1870f4afffe2b4c775a7bdc9cc8 run #0: crashed: unexpected kernel reboot run #1: crashed: unexpected kernel reboot run #2: crashed: unexpected kernel reboot run #3: crashed: unexpected kernel reboot run #4: crashed: unexpected kernel reboot run #5: crashed: unexpected kernel reboot run #6: crashed: unexpected kernel reboot run #7: crashed: unexpected kernel reboot run #8: crashed: unexpected kernel reboot run #9: crashed: no output from test machine testing release v4.18 testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.1.0 kernel signature: 4f7e0dc9148a3357283826ab8bd276adb8bee4dfdc37d82bba96843e2611e46f all runs: crashed: unexpected kernel reboot testing release v4.17 testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.1.0 kernel signature: 5b6d91c587ee2e42b21734f721d7e46a90f2295cdca308ef8c312b35f0bbd650 all runs: crashed: unexpected kernel reboot testing release v4.16 testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.1.0 kernel signature: 68dfc09379a5df03c45ed7a4f2b909b592a04591f0f49f3922ce9208c7d98007 all runs: crashed: unexpected kernel reboot testing release v4.15 testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.1.0 kernel signature: 22e77add8970d0697947d6f8b62a060ff667ba4afb4d617258cccaf3069ac603 run #0: crashed: unexpected kernel reboot run #1: crashed: unexpected kernel reboot run #2: crashed: unexpected kernel reboot run #3: crashed: unexpected kernel reboot run #4: crashed: unexpected kernel reboot run #5: crashed: unexpected kernel reboot run #6: crashed: unexpected kernel reboot run #7: crashed: unexpected kernel reboot run #8: crashed: unexpected kernel reboot run #9: crashed: no output from test machine testing release v4.14 testing commit bebc6082da0a9f5d47a1ea2edc099bf671058bd4 with gcc (GCC) 8.1.0 kernel signature: a6546335911ddf941f23a7eac86aa0301d7d8988c231da279aca880c375a3ef8 all runs: crashed: unexpected kernel reboot testing release v4.13 testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.1.0 kernel signature: 443dfffd97e174b8a922e65bfd6895abf7299be285e45faa4bdcba1da8d93efe all runs: crashed: unexpected kernel reboot testing release v4.12 testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.1.0 kernel signature: 7e549b482fb0d8aa52a8cadf3abbcc6f043a7cff1cfe0444fa99b33a955fc339 all runs: crashed: BUG: sleeping function called from invalid context in tap_get_minor testing release v4.11 testing commit a351e9b9fc24e982ec2f0e76379a49826036da12 with gcc (GCC) 7.3.0 kernel signature: 84e717b96f2d3d12efffd3972d3b5e0698c8f7b4daee7a69ec6289827641537d all runs: crashed: BUG: sleeping function called from invalid context in tap_get_minor testing release v4.10 testing commit c470abd4fde40ea6a0846a2beab642a578c0b8cd with gcc (GCC) 5.5.0 kernel signature: 0c8b1007aa7e3b555695dd920215933c5500539a26a4e24d909779a4af7e39fe all runs: crashed: unexpected kernel reboot testing release v4.9 testing commit 69973b830859bc6529a7a0468ba0d80ee5117826 with gcc (GCC) 5.5.0 kernel signature: 81f27346446f87517a0f8ce7c7bc5ca186ec4cda2846ed47ee73a521c8040e19 all runs: crashed: unexpected kernel reboot testing release v4.8 testing commit c8d2bc9bc39ebea8437fd974fdbc21847bb897a3 with gcc (GCC) 5.5.0 kernel signature: 6ea1736467bd15754df0d093c5452561606561c9349d1e129ddc0ae219f1177e all runs: crashed: unexpected kernel reboot testing release v4.7 testing commit 523d939ef98fd712632d93a5a2b588e477a7565e with gcc (GCC) 5.5.0 kernel signature: fa1605cac64a71a84a983752824210b240fdadb6a186d9bb7f195b1a80a4ec46 run #0: crashed: general protection fault in rt6_score_route run #1: crashed: INFO: trying to register non-static key in addrconf_verify_rtnl run #2: crashed: general protection fault in ipv6_chk_addr_and_flags run #3: crashed: unexpected kernel reboot run #4: crashed: general protection fault in ipv6_add_addr run #5: crashed: general protection fault in check_lifetime run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in nf_hook_slow run #7: crashed: general protection fault in ipv6_get_ifaddr run #8: crashed: unexpected kernel reboot run #9: crashed: general protection fault in netprio_prio testing release v4.6 testing commit 2dcd0af568b0cf583645c8a317dd12e344b1c72a with gcc (GCC) 5.5.0 kernel signature: 3e9221b080659c693c6aed6c19328903274686907b41e8fe9a4de1f63c40fdcf all runs: crashed: WARNING in sysfs_warn_dup revisions tested: 22, total time: 3h59m33.354676048s (build: 1h57m53.523692208s, test: 1h58m49.836077975s) the crash already happened on the oldest tested release commit msg: Linux 4.6 crash: WARNING in sysfs_warn_dup IPv6: ADDRCONF(NETDEV_UP): bridge_slave_0: link is not ready IPv6: ADDRCONF(NETDEV_UP): bridge0: link is not ready bond0: Enslaving bond_slave_1 as an active interface with an up link IPv6: ADDRCONF(NETDEV_UP): bridge_slave_1: link is not ready ------------[ cut here ]------------ WARNING: CPU: 0 PID: 7458 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x7b/0xa0 fs/sysfs/dir.c:30 sysfs: cannot create duplicate filename '/class/macvtap/tap50' Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 7458 Comm: syz-executor.1 Not tainted 4.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 1ffffffff0d95756 ffff8800b312efb0 ffffffff82c74fc6 ffffffff85c81040 ffff8800b312f088 ffffffff85d2bac0 ffffffff81922ccb ffff8800b312f078 ffffffff8160cf4e 0000000041b58ab3 ffffffff868f1f61 ffffffff8160cd9f Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xe6/0x120 lib/dump_stack.c:51 [] ? sysfs_warn_dup+0x7b/0xa0 fs/sysfs/dir.c:30 [] panic+0x1af/0x348 kernel/panic.c:152 [] ? set_ti_thread_flag+0xf/0xf include/linux/thread_info.h:73 [] ? sysfs_warn_dup+0x7b/0xa0 fs/sysfs/dir.c:30 [] __warn+0x18d/0x1b0 kernel/panic.c:504 [] warn_slowpath_fmt+0x92/0xb0 kernel/panic.c:527 [] ? __warn+0x1b0/0x1b0 kernel/panic.c:494 [] ? spin_unlock_irqrestore include/linux/spinlock.h:362 [inline] [] ? kernfs_path_from_node+0x4a/0x60 fs/kernfs/dir.c:234 [] sysfs_warn_dup+0x7b/0xa0 fs/sysfs/dir.c:30 [] sysfs_do_create_link_sd.isra.2+0xd1/0xf0 fs/sysfs/symlink.c:51 [] sysfs_do_create_link fs/sysfs/symlink.c:80 [inline] [] sysfs_create_link+0x43/0xb0 fs/sysfs/symlink.c:92 [] device_add_class_symlinks drivers/base/core.c:891 [inline] [] device_add+0x689/0x1360 drivers/base/core.c:1086 [] ? kfree_const+0x1d/0x20 mm/util.c:35 [] ? device_private_init+0x180/0x180 drivers/base/core.c:996 [] ? kfree_const+0x1d/0x20 mm/util.c:35 [] ? kobject_set_name_vargs+0xb4/0x130 lib/kobject.c:285 [] device_create_groups_vargs+0x1c8/0x220 drivers/base/core.c:1709 [] device_create_vargs drivers/base/core.c:1749 [inline] [] device_create+0x88/0xa0 drivers/base/core.c:1785 [] ? device_create_vargs+0x20/0x20 drivers/base/core.c:1751 [] ? macvlan_set_mac_address+0x150/0x150 drivers/net/macvlan.c:697 [] macvtap_device_event+0x1c4/0x2a0 drivers/net/macvtap.c:1298 [] notifier_call_chain+0x8b/0x170 kernel/notifier.c:93 [] __raw_notifier_call_chain kernel/notifier.c:394 [inline] [] raw_notifier_call_chain+0x11/0x20 kernel/notifier.c:401 [] call_netdevice_notifiers_info+0x47/0x80 net/core/dev.c:1643 [] call_netdevice_notifiers net/core/dev.c:1659 [inline] [] register_netdevice+0x88a/0xce0 net/core/dev.c:7027 [] ? netdev_change_features+0x80/0x80 net/core/dev.c:6801 [] ? dev_get_nest_level+0x10c/0x1a0 net/core/dev.c:5974 [] macvlan_common_newlink+0x8b9/0x1090 drivers/net/macvlan.c:1316 [] macvtap_newlink+0xbf/0x110 drivers/net/macvtap.c:471 [] ? __netlink_ns_capable+0xc7/0xf0 net/netlink/af_netlink.c:783 [] rtnl_newlink+0xd4b/0x1230 net/core/rtnetlink.c:2466 [] ? rtnl_link_ops_get+0x5d/0x90 net/core/rtnetlink.c:284 [] ? rtnl_newlink+0x319/0x1230 net/core/rtnetlink.c:2322 [] ? rtnl_setlink+0x2f0/0x2f0 net/core/rtnetlink.c:2067 [] ? debug_lockdep_rcu_enabled+0x77/0x90 kernel/rcu/update.c:261 [] ? lookup_chain_cache kernel/locking/lockdep.c:2133 [inline] [] ? validate_chain kernel/locking/lockdep.c:2231 [inline] [] ? __lock_acquire+0x1a38/0x5560 kernel/locking/lockdep.c:3329 [] ? debug_check_no_locks_freed+0x3c0/0x3c0 include/linux/sched.h:1954 [] ? __netlink_ns_capable+0xc7/0xf0 net/netlink/af_netlink.c:783 [] rtnetlink_rcv_msg+0x222/0x680 net/core/rtnetlink.c:3513 [] ? __trace_hardirqs_on_caller kernel/locking/lockdep.c:2680 [inline] [] ? trace_hardirqs_on_caller+0x44c/0x5e0 kernel/locking/lockdep.c:2727 [] ? rtnetlink_rcv+0x30/0x30 net/core/rtnetlink.c:3521 [] ? __mutex_lock_common kernel/locking/mutex.c:601 [inline] [] ? mutex_lock_nested+0x638/0xb30 kernel/locking/mutex.c:618 [] ? rtnl_lock net/core/rtnetlink.c:70 [inline] [] ? rtnetlink_rcv+0x16/0x30 net/core/rtnetlink.c:3518 [] ? rcu_read_lock include/linux/rcupdate.h:871 [inline] [] ? netlink_lookup+0xd4/0x630 net/netlink/af_netlink.c:457 [] netlink_rcv_skb+0x242/0x350 net/netlink/af_netlink.c:2277 [] ? rtnetlink_rcv+0x30/0x30 net/core/rtnetlink.c:3521 [] rtnetlink_rcv+0x25/0x30 net/core/rtnetlink.c:3519 [] netlink_unicast_kernel net/netlink/af_netlink.c:1214 [inline] [] netlink_unicast+0x455/0x660 net/netlink/af_netlink.c:1240 [] ? netlink_deliver_tap_kernel net/netlink/af_netlink.c:275 [inline] [] ? netlink_unicast_kernel net/netlink/af_netlink.c:1213 [inline] [] ? netlink_unicast+0x3b5/0x660 net/netlink/af_netlink.c:1240 [] ? netlink_attachskb+0x730/0x730 include/linux/sched.h:2918 [] netlink_sendmsg+0x893/0xb40 net/netlink/af_netlink.c:1786 [] ? netlink_unicast+0x660/0x660 include/net/sock.h:1975 [] ? __might_fault+0xf1/0x1b0 mm/memory.c:3876 [] ? netlink_unicast+0x660/0x660 include/net/sock.h:1975 [] sock_sendmsg_nosec net/socket.c:612 [inline] [] sock_sendmsg+0xb5/0xf0 net/socket.c:622 [] SYSC_sendto+0x1c9/0x300 net/socket.c:1648 [] ? SYSC_connect+0x2a0/0x2a0 net/socket.c:1540 [] ? rcu_read_unlock include/linux/rcupdate.h:922 [inline] [] ? mntput_no_expire+0xb1/0x600 fs/namespace.c:1095 [] ? rcu_lock_release include/linux/rcupdate.h:491 [inline] [] ? rcu_read_unlock include/linux/rcupdate.h:926 [inline] [] ? mntput_no_expire+0xce/0x600 fs/namespace.c:1095 [] ? mnt_get_count+0x1c0/0x1c0 fs/namespace.c:184 [] ? mntput+0x52/0x70 fs/namespace.c:1143 [] ? ___might_sleep+0x331/0x440 kernel/sched/core.c:7435 [] ? __trace_hardirqs_on_caller kernel/locking/lockdep.c:2680 [inline] [] ? trace_hardirqs_on_caller+0x44c/0x5e0 kernel/locking/lockdep.c:2727 [] ? trace_hardirqs_on_thunk+0x1b/0x1d [] SyS_sendto+0x9/0x10 net/socket.c:1616 [] entry_SYSCALL_64_fastpath+0x23/0xc1 Kernel Offset: disabled