bisecting cause commit starting from 513a24ffb3f96a1eedc1f346616814f55ecb11da building syzkaller on 365fba2440cee3aed74c774867a1f43e3e2f7aac testing commit 513a24ffb3f96a1eedc1f346616814f55ecb11da with gcc (GCC) 8.1.0 kernel signature: d7dde0236153a2103173731012682f299249907272f89a0dfd8ec56dac4682dd all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v5.6 testing commit 7111951b8d4973bda27ff663f2cf18b663d15b48 with gcc (GCC) 8.1.0 kernel signature: 49b85c93dc881f2405f8b14f2e05c0755a7a9ad48bb15f8da352f21055bfb5f8 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v5.5 testing commit d5226fa6dbae0569ee43ecfc08bdcd6770fc4755 with gcc (GCC) 8.1.0 kernel signature: 86ebc49f1ff8580d50f579e932c6500be3ee4d15cce4984f60e54ef9f04a28b1 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v5.4 testing commit 219d54332a09e8d8741c1e1982f5eae56099de85 with gcc (GCC) 8.1.0 kernel signature: b51d50d0209df5543f25fab9db323e4c31266499f2b51bdef1e4593ac0d0c065 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v5.3 testing commit 4d856f72c10ecb060868ed10ff1b1453943fc6c8 with gcc (GCC) 8.1.0 kernel signature: 3a399f590ce97b4d007705ced49c43f9b48f7cfba1ae1b49015ee2aa94bd1f4d all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v5.2 testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.1.0 kernel signature: b88cc45835918891cf2eaa4e7b3e5ecdc6482490bc291bcea5d5845148681d56 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v5.1 testing commit e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd with gcc (GCC) 8.1.0 kernel signature: 8b1addcb3918f76f97dbab92443fcc3ba054e83272be493da8dfdc079064cf9e all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v5.0 testing commit 1c163f4c7b3f621efff9b28a47abb36f7378d783 with gcc (GCC) 8.1.0 kernel signature: dde1aac997751b161a14280d7da1726f69bab209dcaaa3248db912acd7d3d27d all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v4.20 testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.1.0 kernel signature: fe7ca03d058a697d9cfd273c320ad47925595fb413d7ef640386c5a7af013ab5 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v4.19 testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.1.0 kernel signature: 972dfde9c7c2fa77fc4753989152fc62ea67a0ed802c39ace6b188b8eca7dea8 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v4.18 testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.1.0 kernel signature: 258e6ec0f3778037c16b1de4fcb25a857c8df5a68e6c1f43c1a6f8e27fbda534 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v4.17 testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.1.0 kernel signature: 896338d9ef0eb8f0528a58e21417631498a84ed3afec24a94474155baf1fcc98 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v4.16 testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.1.0 kernel signature: 943c090c1aa5ec0063d9c2c2e76d0f6f6e099f06b0933fa35fa5528b4691231a all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v4.15 testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.1.0 kernel signature: 75bb829bc98e4b4970217ad1a7fc6dd6b9a9f3a8de6cdf6eb3490f48e06e872c all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v4.14 testing commit bebc6082da0a9f5d47a1ea2edc099bf671058bd4 with gcc (GCC) 8.1.0 kernel signature: da6b5a95cba2ab14bf27e4b3bf51e4bc29e874e33fe9976369c7ea50884789b5 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v4.13 testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.1.0 kernel signature: 07660c151a04d6802791fb028ada16c79d300c7e87275a9a5f94cbc62fd46b3d all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v4.12 testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.1.0 kernel signature: 8f47e9443e00db86175fa72d4f22e2dd735da030d6537d0acff219a147dd8067 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: 27d2207d642f4caa522221b66d0a7ea492822304d150ee17471057ca1b59a177 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: 16371f22af58ef1c999081ebce30828ab652c571edae53b97c435b6743053202 all runs: crashed: KASAN: null-ptr-deref Write testing release v4.9 testing commit 69973b830859bc6529a7a0468ba0d80ee5117826 with gcc (GCC) 5.5.0 kernel signature: dd25da2b00f28c3e0ae2c6347d6af55fe40567d5806980bbfb9b95ac4394254d all runs: crashed: KASAN: null-ptr-deref Write testing release v4.8 testing commit c8d2bc9bc39ebea8437fd974fdbc21847bb897a3 with gcc (GCC) 5.5.0 kernel signature: 0eed8d3a323a1bd7833357cdad507f75692c8e0f261bc00043646674af098377 all runs: crashed: KASAN: null-ptr-deref Write testing release v4.7 testing commit 523d939ef98fd712632d93a5a2b588e477a7565e with gcc (GCC) 5.5.0 kernel signature: 59a2bdefb209bda99c94b758621fa7cdec3c8398c0772a121dd30cbd8aa2e0db all runs: crashed: KASAN: null-ptr-deref Write testing release v4.6 testing commit 2dcd0af568b0cf583645c8a317dd12e344b1c72a with gcc (GCC) 5.5.0 kernel signature: d04afdafdea447be5822c3485b2caf472065c7484262f3a2d7674de1700c7e43 all runs: crashed: WARNING in sysfs_warn_dup revisions tested: 23, total time: 3h21m11.944366254s (build: 2h6m16.937168521s, test: 1h12m5.503811386s) the crash already happened on the oldest tested release commit msg: Linux 4.6 crash: WARNING in sysfs_warn_dup IPv6: ADDRCONF(NETDEV_UP): bridge0: link is not ready bond0: Enslaving bond_slave_0 as an active interface with an up link 8021q: adding VLAN 0 to HW filter on device bond0 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 5908 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: 5908 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 ffff8800b992efc8 ffffffff82c65932 ffffffff85c81040 ffff8800b992f0a0 ffffffff85d2bb00 ffffffff8191b86b 0000000000000009 ffff8800b992f090 ffffffff8160d374 0000000041b58ab3 ffffffff868f058a 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