bisecting cause commit starting from de2e69cfe54a8f2ed4b75f09d3110c514f45d38e building syzkaller on 21f1765e15967196c4f3c9756ae4ec8a1fa7996d testing commit de2e69cfe54a8f2ed4b75f09d3110c514f45d38e with gcc (GCC) 8.1.0 kernel signature: c90ab9d6654242ecb4748064011fe28f6c6656ad49479a999e1d6615b06a04ea all runs: crashed: kernel panic: Fatal exception testing release v5.7 testing commit 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162 with gcc (GCC) 8.1.0 kernel signature: 28309118e2fbe3bc4492e864bb869ed1e00bdb8c01b87a5c013a0bf7f2f5ec8c all runs: crashed: divide error in fbcon_switch testing release v5.6 testing commit 7111951b8d4973bda27ff663f2cf18b663d15b48 with gcc (GCC) 8.1.0 kernel signature: 2c05c04ec2050565326799f7033df3e67f947677090ad3c19f2f1ced01e694a1 all runs: crashed: divide error in fbcon_switch testing release v5.5 testing commit d5226fa6dbae0569ee43ecfc08bdcd6770fc4755 with gcc (GCC) 8.1.0 kernel signature: 3b63ae1726b695825b19afcafb1389e5697cb51cb4a73e4b8f1602a24c3d7f14 all runs: crashed: divide error in fbcon_switch testing release v5.4 testing commit 219d54332a09e8d8741c1e1982f5eae56099de85 with gcc (GCC) 8.1.0 kernel signature: a5d793949ca41a9718ae6367637a3b3a6e3199d0cfde33d74f6cf1a57662ec6b all runs: crashed: divide error in fbcon_switch testing release v5.3 testing commit 4d856f72c10ecb060868ed10ff1b1453943fc6c8 with gcc (GCC) 8.1.0 kernel signature: 7af8df0053112ad22c47b28113cb132d9a7c7cfe56d22c75bbd2a259cb4a94c9 all runs: crashed: divide error in fbcon_switch testing release v5.2 testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.1.0 kernel signature: 21e452cdd812c2287c11536c8f71c82267dc4bfe033a4b67fc6e8a4743b1eeae all runs: crashed: divide error in fbcon_switch testing release v5.1 testing commit e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd with gcc (GCC) 8.1.0 kernel signature: 8574e01ee5a6f3142dc6bbe1e5735f04f968628d6f4e84f83250972f21afb18a all runs: crashed: divide error in fbcon_switch testing release v5.0 testing commit 1c163f4c7b3f621efff9b28a47abb36f7378d783 with gcc (GCC) 8.1.0 kernel signature: b939f9d871844d7d6677cbc7a65a2d880160ad6df537b170a6ea9296b6128577 all runs: crashed: divide error in fbcon_switch testing release v4.20 testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.1.0 kernel signature: ad81f846135d6ffd6f7069fdf7916c5a62c8e8dd5516731cd984a6886e44d4a3 all runs: crashed: divide error in fbcon_switch testing release v4.19 testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.1.0 kernel signature: 28c4b08ee94954f4c179a8c3290aaf8073f6470d2e4dc4e12bdffdd848a75f69 all runs: crashed: divide error in fbcon_switch testing release v4.18 testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.1.0 kernel signature: 64d9efe79e23ca28baaadf15313deed2cd524a31a98691933ed203e7a93e3613 all runs: crashed: divide error in fbcon_switch testing release v4.17 testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.1.0 kernel signature: 23c02aedd32142ab8d89cd16276d79336d279ce560ab0612915f7b1534ff83d0 all runs: crashed: divide error in fbcon_switch testing release v4.16 testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.1.0 kernel signature: 5fb1a7f5569d43ddde5028a1d748c5e69b9101dab0ca0d77431ea2dc022f51c6 all runs: crashed: divide error in fbcon_switch testing release v4.15 testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.1.0 kernel signature: 0b579058975737b840e79fc1a04aef899929ecb5e8b84572a9c4f2e1dad2066e all runs: crashed: divide error in fbcon_switch testing release v4.14 testing commit bebc6082da0a9f5d47a1ea2edc099bf671058bd4 with gcc (GCC) 8.1.0 kernel signature: 22fb0ecead64d7e3cb574b56eb1dc8e5253855d4ab8e739debfbd895eaab7c5f all runs: crashed: divide error in fbcon_switch testing release v4.13 testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.1.0 kernel signature: 9293a4fa6642f153a3fb52b6db811604a29f210ae18644f044c554e2f891a66b all runs: crashed: divide error in fbcon_switch testing release v4.12 testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.1.0 kernel signature: 623496515d463eb05ba90c0bf4f6123a1b835392b5fd38d5c7d61009c57f1664 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: eef05efcf6beab58c68b29bfad625c7fb880fd82c7ce0e4b4f546ef9e4a2b69f 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: 564b2db549e113f444811d823ef8415e5d5eb223f37dffe40511e2d5913271a7 all runs: crashed: divide error in fbcon_switch testing release v4.9 testing commit 69973b830859bc6529a7a0468ba0d80ee5117826 with gcc (GCC) 5.5.0 kernel signature: a7931e327b2a895acbdfd89a7c786e574791d3af2641f6dd383bc5d53139f994 all runs: crashed: divide error in fbcon_switch testing release v4.8 testing commit c8d2bc9bc39ebea8437fd974fdbc21847bb897a3 with gcc (GCC) 5.5.0 kernel signature: 03905d8936422902e469e3485e557c4412e63638ec5ba63cb1fc4accc3be3d13 all runs: crashed: divide error in fbcon_switch testing release v4.7 testing commit 523d939ef98fd712632d93a5a2b588e477a7565e with gcc (GCC) 5.5.0 kernel signature: a7a7bc9235a07a9bf6bb0ab945aa78d0ae8569bac7e0ffba5cca742985f0d543 all runs: crashed: divide error in fbcon_switch testing release v4.6 testing commit 2dcd0af568b0cf583645c8a317dd12e344b1c72a with gcc (GCC) 5.5.0 kernel signature: 645f3ae064407585df0e88cb5d5a020cb5d80ecb3e2b23997993b2ecce3319ca all runs: crashed: WARNING in sysfs_warn_dup revisions tested: 24, total time: 3h37m33.086570931s (build: 2h13m57.887228446s, test: 1h18m23.916547902s) 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 bridge0: port 1(bridge_slave_0) entered blocking state bridge0: port 1(bridge_slave_0) entered disabled state device bridge_slave_0 entered promiscuous mode ------------[ 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.2 Not tainted 4.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 0000000000000000 ffff8800b3f3efc8 ffffffff82c65e52 ffffffff85c81040 ffff8800b3f3f0a0 ffffffff85d2bb80 ffffffff8191bd7b 0000000000000009 ffff8800b3f3f090 ffffffff8160d884 0000000041b58ab3 ffffffff868f3a9a 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