bisecting cause commit starting from 7b287a5c6ac518c415a258f2aa7b1ebb25c263d2 building syzkaller on 8df85ed9883abc2a200858f44f22c11c602d218a testing commit 7b287a5c6ac518c415a258f2aa7b1ebb25c263d2 with gcc (GCC) 8.1.0 kernel signature: 911b3d5fec2e23a117941c6f9590a24d84c122d95d2710b5806c412930624f07 all runs: crashed: WARNING in ipvlan_unregister_nf_hook testing release v5.7 testing commit 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162 with gcc (GCC) 8.1.0 kernel signature: 6bdf7558d189378ea33568b7f9a6015e7194873df3a633502b0922bb0f1af66c all runs: crashed: WARNING in ipvlan_unregister_nf_hook testing release v5.6 testing commit 7111951b8d4973bda27ff663f2cf18b663d15b48 with gcc (GCC) 8.1.0 kernel signature: db7aa4ab6bc8a5a1dc9dccce5f51cb5f2d2852f25d5032b7533d6aca8a9b8256 all runs: crashed: WARNING in ipvlan_unregister_nf_hook testing release v5.5 testing commit d5226fa6dbae0569ee43ecfc08bdcd6770fc4755 with gcc (GCC) 8.1.0 kernel signature: 0077e0b6786db84c5723f0e7cda334e7f4d515379603736aa05a24ea6ec47f08 all runs: crashed: WARNING in ipvlan_unregister_nf_hook testing release v5.4 testing commit 219d54332a09e8d8741c1e1982f5eae56099de85 with gcc (GCC) 8.1.0 kernel signature: 16dbb6101cedaaad4bd4af428c7ba9f1fe3bcfe0bb37d19cf9ff9b4b32aea8ae all runs: crashed: WARNING in ipvlan_unregister_nf_hook testing release v5.3 testing commit 4d856f72c10ecb060868ed10ff1b1453943fc6c8 with gcc (GCC) 8.1.0 kernel signature: d6148a204aae5684af6792a69f05ef418df3c14b7c0dc4a6502119c4b49fbdd4 all runs: crashed: WARNING in ipvlan_unregister_nf_hook testing release v5.2 testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.1.0 kernel signature: 46276fe9ef481d66250e3585fd600d47b165c5bfaded195a139dd741a5f78956 all runs: crashed: WARNING in ipvlan_unregister_nf_hook testing release v5.1 testing commit e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd with gcc (GCC) 8.1.0 kernel signature: 4641418aef198ee4a185537b39556d3b5b1307c3e50a02095e06f0ee1605769c all runs: crashed: WARNING in ipvlan_unregister_nf_hook testing release v5.0 testing commit 1c163f4c7b3f621efff9b28a47abb36f7378d783 with gcc (GCC) 8.1.0 kernel signature: f44bfea772d8a7bab4a092cff5a8b590c9080d98abcdfc477ba49961df3424a0 all runs: crashed: WARNING in ipvlan_unregister_nf_hook testing release v4.20 testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.1.0 kernel signature: f39bd418eef7519faa8b27cbc6b827242fbef7caf6917f53038c98491743448d all runs: crashed: WARNING in ipvlan_unregister_nf_hook testing release v4.19 testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.1.0 kernel signature: 9c58113695e756e9f78eab43f311de1a0e91850531c6ecdda9b7725fd60f8fcf run #0: crashed: WARNING in ipvlan_unregister_nf_hook run #1: crashed: WARNING in ipvlan_unregister_nf_hook run #2: crashed: WARNING in ipvlan_unregister_nf_hook run #3: crashed: WARNING in ipvlan_unregister_nf_hook run #4: crashed: WARNING in ipvlan_unregister_nf_hook run #5: crashed: WARNING in ipvlan_unregister_nf_hook run #6: crashed: WARNING in ipvlan_unregister_nf_hook run #7: crashed: WARNING in ipvlan_unregister_nf_hook run #8: crashed: WARNING in ipvlan_unregister_nf_hook run #9: crashed: WARNING in batadv_is_on_batman_iface testing release v4.18 testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.1.0 kernel signature: cbac6450123a3e4c6018a885f7f745fb82f9ffb83cf836aa49ba6f65a6a4baa7 all runs: crashed: WARNING in ipvlan_unregister_nf_hook testing release v4.17 testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.1.0 kernel signature: 30b33f02239b20aaefad5e33649998aab5ca82b226040043c8ac796e1d8b654e run #0: crashed: WARNING in ipvlan_unregister_nf_hook run #1: crashed: WARNING in ipvlan_unregister_nf_hook run #2: crashed: WARNING in ipvlan_unregister_nf_hook run #3: crashed: WARNING in batadv_is_on_batman_iface run #4: crashed: WARNING in ipvlan_unregister_nf_hook run #5: crashed: WARNING in ipvlan_unregister_nf_hook run #6: crashed: WARNING in ipvlan_unregister_nf_hook run #7: crashed: WARNING in ipvlan_unregister_nf_hook run #8: crashed: WARNING in ipvlan_unregister_nf_hook run #9: crashed: WARNING in ipvlan_unregister_nf_hook testing release v4.16 testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.1.0 kernel signature: fb49d605f2b28e8f7ab8dac8d6d329c0264172c532bad3d66ff694f562b637c2 all runs: crashed: WARNING in ipvlan_unregister_nf_hook testing release v4.15 testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.1.0 kernel signature: a915b77c354482d9cb8277548ffa089143459e94b37977deb7cdada54b07d1b7 all runs: crashed: WARNING in ipvlan_unregister_nf_hook testing release v4.14 testing commit bebc6082da0a9f5d47a1ea2edc099bf671058bd4 with gcc (GCC) 8.1.0 kernel signature: 323dbc16211ed42d207d0d25e2a6de7de5641c2c2b71ec3470abe08c218759f2 all runs: crashed: WARNING in ipvlan_unregister_nf_hook testing release v4.13 testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.1.0 kernel signature: 8f9804e69ade0184b893ebe58fb923e2add4c71778993b60ccc0ad24bf4d1560 run #0: crashed: WARNING in ipvlan_unregister_nf_hook run #1: crashed: WARNING in ipvlan_unregister_nf_hook run #2: crashed: WARNING in ipvlan_unregister_nf_hook run #3: crashed: WARNING in ipvlan_unregister_nf_hook run #4: crashed: WARNING in ipvlan_unregister_nf_hook run #5: crashed: WARNING in ipvlan_unregister_nf_hook run #6: crashed: WARNING in batadv_is_on_batman_iface run #7: crashed: WARNING in ipvlan_unregister_nf_hook run #8: crashed: WARNING in ipvlan_unregister_nf_hook run #9: crashed: WARNING in batadv_is_on_batman_iface testing release v4.12 testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.1.0 kernel signature: 7053f821b39c1a472cc5d7b8c83620be5db39d3e9b1bba1d2c6b20af5dce10b0 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: e09f4bc00230c8190f7849eaa4a0eb38c82c87123ff8017ef272a61dfa702ba9 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: d22058b3f80d0ee65538b49d934025d85f8ae1ad083ee200f20fb9ac928be4b1 run #0: crashed: WARNING in batadv_is_on_batman_iface run #1: crashed: WARNING in batadv_is_on_batman_iface run #2: crashed: WARNING in batadv_is_on_batman_iface run #3: crashed: WARNING in batadv_is_on_batman_iface run #4: crashed: WARNING in batadv_is_on_batman_iface run #5: crashed: WARNING in batadv_is_on_batman_iface run #6: crashed: WARNING in batadv_is_on_batman_iface run #7: crashed: WARNING in nf_unregister_net_hook run #8: crashed: WARNING in batadv_is_on_batman_iface run #9: crashed: WARNING in batadv_is_on_batman_iface testing release v4.9 testing commit 69973b830859bc6529a7a0468ba0d80ee5117826 with gcc (GCC) 5.5.0 kernel signature: f0ada69a5621ffab4c7be48a65169911b190f02155963e033895261d9c4f8d13 run #0: crashed: WARNING in batadv_is_on_batman_iface run #1: crashed: WARNING in batadv_is_on_batman_iface run #2: crashed: WARNING in batadv_is_on_batman_iface run #3: crashed: WARNING in batadv_is_on_batman_iface run #4: crashed: WARNING in batadv_is_on_batman_iface run #5: crashed: WARNING in batadv_is_on_batman_iface run #6: crashed: WARNING in nf_unregister_net_hook run #7: crashed: WARNING in batadv_is_on_batman_iface run #8: crashed: WARNING in batadv_is_on_batman_iface run #9: crashed: WARNING in batadv_is_on_batman_iface testing release v4.8 testing commit c8d2bc9bc39ebea8437fd974fdbc21847bb897a3 with gcc (GCC) 5.5.0 kernel signature: b26c5fd5f75cf088fe8f466efa0a1eba536b61eadb37c5a59e6b3aeb3ce64075 all runs: crashed: WARNING in batadv_is_on_batman_iface testing release v4.7 testing commit 523d939ef98fd712632d93a5a2b588e477a7565e with gcc (GCC) 5.5.0 kernel signature: 08f4e063ccda3e0d75aea062d608147309e7ecba7cf924bf91859eba6f724d56 run #0: crashed: KASAN: use-after-free Read in macsec_notify run #1: crashed: WARNING in batadv_is_on_batman_iface run #2: crashed: WARNING in batadv_is_on_batman_iface run #3: crashed: WARNING in batadv_is_on_batman_iface run #4: crashed: KASAN: use-after-free Read in macsec_notify run #5: crashed: WARNING in batadv_is_on_batman_iface run #6: crashed: WARNING in batadv_is_on_batman_iface run #7: crashed: WARNING in batadv_is_on_batman_iface run #8: crashed: WARNING in batadv_is_on_batman_iface run #9: crashed: WARNING in batadv_is_on_batman_iface testing release v4.6 testing commit 2dcd0af568b0cf583645c8a317dd12e344b1c72a with gcc (GCC) 5.5.0 kernel signature: 5df2973738167e472a4ab9f880654265d37371cde457ace75b43d42f54f08130 all runs: crashed: WARNING in sysfs_warn_dup revisions tested: 24, total time: 3h34m48.463286747s (build: 2h10m16.287840917s, test: 1h20m25.824772868s) the crash already happened on the oldest tested release commit msg: Linux 4.6 crash: WARNING in sysfs_warn_dup IPv6: ADDRCONF(NETDEV_UP): hsr_slave_1: link is not ready IPv6: ADDRCONF(NETDEV_UP): bridge_slave_0: link is not ready bond0: Enslaving bond_slave_0 as an active interface with an up link IPv6: ADDRCONF(NETDEV_UP): bridge_slave_1: link is not ready ------------[ cut here ]------------ WARNING: CPU: 1 PID: 5881 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: 1 PID: 5881 Comm: syz-executor.5 Not tainted 4.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 0000000000000000 ffff8801296eefc8 ffffffff82c65e52 ffffffff85c81040 ffff8801296ef0a0 ffffffff85d2bb80 ffffffff8191bd7b 0000000000000009 ffff8801296ef090 ffffffff8160d884 0000000041b58ab3 ffffffff868f8c5a Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0x136/0x1d4 lib/dump_stack.c:51 [] panic+0x1af/0x348 kernel/panic.c:152 [] __warn+0x18d/0x1b0 kernel/panic.c:504 [] warn_slowpath_fmt+0x92/0xb0 kernel/panic.c:527 [] sysfs_warn_dup+0x7b/0xa0 fs/sysfs/dir.c:30 [] sysfs_do_create_link_sd.isra.0+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+0x677/0x1350 drivers/base/core.c:1086 [] 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 [] 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+0x8e8/0xd00 net/core/dev.c:7027 [] macvlan_common_newlink+0x8b9/0x1090 drivers/net/macvlan.c:1316 [] macvtap_newlink+0xbf/0x110 drivers/net/macvtap.c:471 [] rtnl_newlink+0xd4b/0x1230 net/core/rtnetlink.c:2466 [] rtnetlink_rcv_msg+0x222/0x680 net/core/rtnetlink.c:3513 [] netlink_rcv_skb+0x242/0x350 net/netlink/af_netlink.c:2277 [] rtnetlink_rcv+0x25/0x30 net/core/rtnetlink.c:3519 [] netlink_unicast_kernel net/netlink/af_netlink.c:1214 [inline] [] netlink_unicast+0x3da/0x560 net/netlink/af_netlink.c:1240 [] netlink_sendmsg+0x9bb/0xb40 net/netlink/af_netlink.c:1786 [] sock_sendmsg_nosec net/socket.c:612 [inline] [] sock_sendmsg+0xb5/0xf0 net/socket.c:622 [] SYSC_sendto net/socket.c:1648 [inline] [] SyS_sendto+0x1ca/0x290 net/socket.c:1616 [] entry_SYSCALL_64_fastpath+0x23/0xc1 Kernel Offset: disabled