bisecting cause commit starting from 63623fd44972d1ed2bfb6e0fb631dfcf547fd1e7 building syzkaller on c88c7b75a4e022b758f4b0f1bf3db8ebb2fb25e6 testing commit 63623fd44972d1ed2bfb6e0fb631dfcf547fd1e7 with gcc (GCC) 8.1.0 kernel signature: af436fa061615b0de4226487f8a73f6eba2c3ae86b55e84eabe6b929d6dc356c all runs: crashed: no output from test machine testing release v5.5 testing commit d5226fa6dbae0569ee43ecfc08bdcd6770fc4755 with gcc (GCC) 8.1.0 kernel signature: dd3b516f9660b4f25f7c3ff74f47106616a42b6c405e21c02a7c7751b04fd5ad all runs: crashed: no output from test machine testing release v5.4 testing commit 219d54332a09e8d8741c1e1982f5eae56099de85 with gcc (GCC) 8.1.0 kernel signature: 24a5cee05bcb4c2aaf50d5461b6ec1451735d50dedbaf28e934f7935a9a035d7 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 v5.3 testing commit 4d856f72c10ecb060868ed10ff1b1453943fc6c8 with gcc (GCC) 8.1.0 kernel signature: 8e37cbc3d4722736916b6a0dae212ee3795471d0df68ec65a3dc01f6ecd1abae 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 v5.2 testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.1.0 kernel signature: bd3606dddb7ed4e54c8aab18f0fef3dde90e9e31a3fed0ef1242e94bd29fb17e run #0: crashed: general protection fault in prepare_exit_to_usermode run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in do_syscall_64 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: unexpected kernel reboot testing release v5.1 testing commit e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd with gcc (GCC) 8.1.0 kernel signature: e046bcb489eacaa321c8607ccb407c8ad2c52cbe61e27087dc71c7d76d9c7d30 all runs: crashed: unexpected kernel reboot testing release v5.0 testing commit 1c163f4c7b3f621efff9b28a47abb36f7378d783 with gcc (GCC) 8.1.0 kernel signature: 3c50cdd15cbc2a81b1ace4a816619105421037008f33702de4dc355ea712bced all runs: crashed: unexpected kernel reboot testing release v4.20 testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.1.0 kernel signature: c69914e021456898d091302f22f135d14dfbd78910ccd4613694aeb07d5b539b all runs: crashed: unexpected kernel reboot testing release v4.19 testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.1.0 kernel signature: db91e3bd751496ab2fa12a977553ec9c70090e64aa2f28fe6b7d7b23e24396da run #0: crashed: general protection fault in update_vsyscall run #1: crashed: unexpected kernel reboot run #2: crashed: unexpected kernel reboot run #3: crashed: unexpected kernel reboot run #4: crashed: BUG: sleeping function called from invalid context in __do_page_fault run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in do_syscall_64 run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in do_syscall_64 run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in do_syscall_64 run #8: crashed: BUG: unable to handle kernel paging request in do_syscall_64 run #9: crashed: unexpected kernel reboot testing release v4.18 testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.1.0 kernel signature: 395a4b6bd4a3b65a787d8898e62b476ba9eb2f1241b8b3e2032529fe9a998019 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 v4.17 testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.1.0 kernel signature: 90e0305ba47e79b573efac484bb0ae3a5efd205d92359a19705c48c10c7afcf2 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 v4.16 testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.1.0 kernel signature: 236ab95d81488b570d8e1ff354ca74b978102835856650a46a4db1629af0d0cc 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 v4.15 testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.1.0 kernel signature: 66d09d984ebbabb7d505f52dcd55a667587d80145019df6131a069d18a88001f 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: 9c15da5f57b71548f4e8f194fbea97b2347f115b939420c35a72d75f9831e9cd all runs: crashed: unexpected kernel reboot testing release v4.13 testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.1.0 kernel signature: 2990489df488bcf7703e1941c74fd2e4ab69315b7a282c288f26fd3203e177ac all runs: crashed: unexpected kernel reboot testing release v4.12 testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.1.0 kernel signature: cf78a9d1c0f257d92501a7ea8cbed6c503ffd4a81d003adafc47f3a6ff4cb796 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: e34b56860d0348b5e779d320aea9db241d3a44987840bed00ade11949bb50f46 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: d58b96d092aee062012c7bbb0216a379e154dd5c96246a914b4cfa734bfd4639 run #0: crashed: BUG: sleeping function called from invalid context in __do_page_fault 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: BUG: sleeping function called from invalid context in __do_page_fault run #8: crashed: BUG: sleeping function called from invalid context in __do_page_fault run #9: crashed: unexpected kernel reboot testing release v4.9 testing commit 69973b830859bc6529a7a0468ba0d80ee5117826 with gcc (GCC) 5.5.0 kernel signature: 8d1493ebf6925aa149de0b8787549e9cc21512cc8a97d53b8e15bc973e7f7e1f all runs: crashed: unexpected kernel reboot testing release v4.8 testing commit c8d2bc9bc39ebea8437fd974fdbc21847bb897a3 with gcc (GCC) 5.5.0 kernel signature: 1f5416cdd9e6aa38dc9eeef250c83e1f5899f33d443c3fc4b363603d5450677b run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in syscall_return_slowpath run #1: crashed: unexpected kernel reboot run #2: crashed: BUG: unable to handle kernel paging request in __switch_to 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: unexpected kernel reboot testing release v4.7 testing commit 523d939ef98fd712632d93a5a2b588e477a7565e with gcc (GCC) 5.5.0 kernel signature: 4db9e0aae3d9e903051d836311eee8281f1c2d0111038e3466cf93c93dc975e2 run #0: crashed: BUG: spinlock bad magic in corrupted run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in syscall_return_slowpath 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: general protection fault in update_vsyscall run #7: crashed: unexpected kernel reboot run #8: crashed: unexpected kernel reboot run #9: crashed: unexpected kernel reboot testing release v4.6 testing commit 2dcd0af568b0cf583645c8a317dd12e344b1c72a with gcc (GCC) 5.5.0 kernel signature: 0add18c314ce46e55d4bae3c97b4f2fedf366934fc52bdbdd92d0dc2d74b66ba all runs: crashed: WARNING in sysfs_warn_dup revisions tested: 22, total time: 4h1m7.963201765s (build: 2h0m9.806322913s, test: 1h58m25.946005626s) the crash already happened on the oldest tested release commit msg: Linux 4.6 crash: WARNING in sysfs_warn_dup 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 IPv6: ADDRCONF(NETDEV_UP): bridge_slave_0: link is not ready ------------[ cut here ]------------ WARNING: CPU: 0 PID: 7021 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: 7021 Comm: syz-executor.4 Not tainted 4.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 1ffffffff0d95756 ffff8800b4baefb0 ffffffff82c74fc6 ffffffff85c81040 ffff8800b4baf088 ffffffff85d2bac0 ffffffff81922ccb ffff8800b4baf078 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