bisecting cause commit starting from fb279f4e238617417b132a550f24c1e86d922558 building syzkaller on fd2a5f28eb5e2b7c83b5e814f53e44e2a5dde24c testing commit fb279f4e238617417b132a550f24c1e86d922558 with gcc (GCC) 8.1.0 kernel signature: af642cec42b3ba27f0679a7f2f06a7bcfa9f2331ac7152b60c825470408e0a53 all runs: crashed: possible deadlock in uart_write testing release v5.5 testing commit d5226fa6dbae0569ee43ecfc08bdcd6770fc4755 with gcc (GCC) 8.1.0 kernel signature: 466c0062d5e40adbb7facc66dc723fbc594e4c8557bb9a91de9e25b837237753 all runs: crashed: possible deadlock in uart_write testing release v5.4 testing commit 219d54332a09e8d8741c1e1982f5eae56099de85 with gcc (GCC) 8.1.0 kernel signature: ba1a0c3df149d0e72bcc8229be9edbc5ab81f9aa08ddfc23a588e0b953918708 all runs: crashed: possible deadlock in uart_write testing release v5.3 testing commit 4d856f72c10ecb060868ed10ff1b1453943fc6c8 with gcc (GCC) 8.1.0 kernel signature: b978f5e30caf36a079129b71913d21c6dd0d58419ed043d5b74d97a30ab76a6c all runs: crashed: no output from test machine testing release v5.2 testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.1.0 kernel signature: bfff48a94554c548020a26124fd6c70993383c90537e3e40ebec7c1b352dd81d all runs: crashed: possible deadlock in uart_write testing release v5.1 testing commit e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd with gcc (GCC) 8.1.0 kernel signature: 8a9b377257feccb4b012b316c291d3ddd39f51d571c6202e7fdf5958f142026a all runs: crashed: possible deadlock in uart_write testing release v5.0 testing commit 1c163f4c7b3f621efff9b28a47abb36f7378d783 with gcc (GCC) 8.1.0 kernel signature: 2bbe517558dd72126ec5dee54dedddfb14f31a198c283811fd2c4992d3e8662b all runs: crashed: possible deadlock in uart_write testing release v4.20 testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.1.0 kernel signature: 0c9dcfe042e9454134001713c1cd3ef43116465561984a0743eacc9d08863cbb all runs: crashed: possible deadlock in uart_write testing release v4.19 testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.1.0 kernel signature: 9f6be2888d4635ab9e0d19a61f396a5cee27832b2a13a24ebe1a9a1ed43703a9 all runs: crashed: possible deadlock in uart_write testing release v4.18 testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.1.0 kernel signature: bbabad92ae68da8176a0c117539d05667576c1d106bfdfebae86ba4e0df7bfe8 all runs: crashed: possible deadlock in uart_write testing release v4.17 testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.1.0 kernel signature: 253311e7fd47e983c9a2040594f42a2bd05e8bf7665d3f5f8df39500a608a5c9 all runs: crashed: possible deadlock in uart_write testing release v4.16 testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.1.0 kernel signature: 315c1fc012eb10ce4b61ed9ff4136beaf54659b0c7481b217328b4c2281c504a all runs: crashed: possible deadlock in uart_write testing release v4.15 testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.1.0 kernel signature: eba99ea0a1a729de89ec9dfeb0e277742c94c6c8941ac763884ff54f4f0dee71 all runs: crashed: possible deadlock in uart_write testing release v4.14 testing commit bebc6082da0a9f5d47a1ea2edc099bf671058bd4 with gcc (GCC) 8.1.0 kernel signature: 68ad12febb71c02376f38842f0938928068eb6b69845812f9370e2ba0bc62470 all runs: crashed: possible deadlock in uart_write testing release v4.13 testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.1.0 kernel signature: 707080cb02eac41b56299da4c4fae4ce39bee35b026cd83e8a6c53b69ebc1bd3 all runs: crashed: possible deadlock in uart_write testing release v4.12 testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.1.0 kernel signature: 1eb80e78a108bba009b8a55db78f1d9c8526d053225a8120834c3c22c8729b7b 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: 471dfbd56615f741b2fff675baa7bf3453f7121594cfe5063cf4ea00268a4182 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: 3930af690781247223a6102deb7feb443eb56f79af636e078d415a1dfbba6706 all runs: crashed: possible deadlock in uart_write testing release v4.9 testing commit 69973b830859bc6529a7a0468ba0d80ee5117826 with gcc (GCC) 5.5.0 kernel signature: bee9914fc8d3f92a00ee3906271341701758fbc6f37868e574d0a4c41e84206f all runs: crashed: possible deadlock in uart_write testing release v4.8 testing commit c8d2bc9bc39ebea8437fd974fdbc21847bb897a3 with gcc (GCC) 5.5.0 kernel signature: 8f71f34ab7a5ff7bb532327afbf7133cc68123ccf3ab49b1078192017a378598 all runs: crashed: possible deadlock in uart_write testing release v4.7 testing commit 523d939ef98fd712632d93a5a2b588e477a7565e with gcc (GCC) 5.5.0 kernel signature: f517038e25cb14b50c82fec7329bb8e7355c6978ad01f8012e26bfc87167afae all runs: crashed: possible deadlock in uart_write testing release v4.6 testing commit 2dcd0af568b0cf583645c8a317dd12e344b1c72a with gcc (GCC) 5.5.0 kernel signature: f57347d7b1631ead48800db607b5c6c7870e92558e19b9055bac98d71ac67b29 all runs: crashed: WARNING in sysfs_warn_dup revisions tested: 22, total time: 4h25m45.840176326s (build: 1h51m50.953716036s, test: 2h31m27.325889307s) the crash already happened on the oldest tested release commit msg: Linux 4.6 crash: WARNING in sysfs_warn_dup bond0: Enslaving bond_slave_0 as an active interface with an up link bond0: Enslaving bond_slave_1 as an active interface with an up link IPv6: ADDRCONF(NETDEV_UP): bridge_slave_0: link is not ready IPv6: ADDRCONF(NETDEV_UP): bridge_slave_1: link is not ready ------------[ cut here ]------------ WARNING: CPU: 1 PID: 7772 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: 7772 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 1ffffffff0d95756 ffff8800ac566fb0 ffffffff82c74fc6 ffffffff85c81040 ffff8800ac567088 ffffffff85d2bac0 ffffffff81922ccb ffff8800ac567078 ffffffff8160cf4e 0000000041b58ab3 ffffffff868f2161 ffffffff8160cd9f Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xe6/0x120 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.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 [] 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+0x88a/0xce0 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+0x455/0x660 net/netlink/af_netlink.c:1240 [] netlink_sendmsg+0x893/0xb40 net/netlink/af_netlink.c:1786 [] sock_sendmsg_nosec net/socket.c:612 [inline] [] sock_sendmsg+0xb5/0xf0 net/socket.c:622 [] SYSC_sendto+0x1c9/0x300 net/socket.c:1648 [] SyS_sendto+0x9/0x10 net/socket.c:1616 [] entry_SYSCALL_64_fastpath+0x23/0xc1 Kernel Offset: disabled