bisecting cause commit starting from 919a23e9d6ccf8b30e6b4c7aa36f8904c99d2dd7 building syzkaller on 41f049cc401ca2a85838b25ceea9e6b3c5966811 testing commit 919a23e9d6ccf8b30e6b4c7aa36f8904c99d2dd7 with gcc (GCC) 8.1.0 kernel signature: 92933947291c22beac65df0e91fdcfa9781a849b3153af00cc7694eba98df6bc all runs: crashed: WARNING in kcm_write_msgs testing release v5.5 testing commit d5226fa6dbae0569ee43ecfc08bdcd6770fc4755 with gcc (GCC) 8.1.0 kernel signature: 12e9c5959cb18408f05c2857fbed18fb8b3735161aeade28e5462e7abe126cdb all runs: crashed: WARNING in kcm_write_msgs testing release v5.4 testing commit 219d54332a09e8d8741c1e1982f5eae56099de85 with gcc (GCC) 8.1.0 kernel signature: e6f43ed24efd6f6e14acb4c1eaf5b617da1001a4bdfce14173311a52b52fff8f all runs: crashed: WARNING in kcm_write_msgs testing release v5.3 testing commit 4d856f72c10ecb060868ed10ff1b1453943fc6c8 with gcc (GCC) 8.1.0 kernel signature: 2d7ffe9cb82296b3aaee4330b6646c282612f10859605ebd4dfe5b46e4a0fa05 all runs: crashed: WARNING in kcm_write_msgs testing release v5.2 testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.1.0 kernel signature: cd8e38166180fc6b9219baec6e852feb946f7c0d4a0fb106e763a89fa7dbb79f all runs: crashed: WARNING in kcm_write_msgs testing release v5.1 testing commit e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd with gcc (GCC) 8.1.0 kernel signature: 197d13e3355472e69eaef054d9cbc1d927947902228c15db3b9ece9b2647e131 all runs: crashed: WARNING in kcm_write_msgs testing release v5.0 testing commit 1c163f4c7b3f621efff9b28a47abb36f7378d783 with gcc (GCC) 8.1.0 kernel signature: d7f07da471064de12b186fbc090e2a976198679148acf84e5655cfddac07f020 all runs: crashed: WARNING in kcm_write_msgs testing release v4.20 testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.1.0 kernel signature: 7aeda24cfb26612056ab5c2e64cf818ca2cf0317ff2bc62663408cfbf1b6b7fc run #0: crashed: WARNING in kcm_write_msgs run #1: crashed: WARNING in corrupted run #2: crashed: WARNING in corrupted run #3: crashed: WARNING in kcm_write_msgs run #4: crashed: WARNING in kcm_write_msgs run #5: crashed: WARNING in kcm_write_msgs run #6: crashed: WARNING in kcm_write_msgs run #7: crashed: WARNING in kcm_write_msgs run #8: crashed: WARNING in kcm_write_msgs run #9: crashed: WARNING in kcm_write_msgs testing release v4.19 testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.1.0 kernel signature: 7710c1d6f40e9239fd9eec6ed51bc059bbd01d3178b48f362528b46ce5006579 run #0: crashed: WARNING in kcm_write_msgs run #1: crashed: WARNING in kcm_write_msgs run #2: crashed: WARNING in kcm_write_msgs run #3: crashed: WARNING in kcm_write_msgs run #4: crashed: WARNING in kcm_write_msgs run #5: crashed: WARNING in kcm_write_msgs run #6: crashed: WARNING in kcm_write_msgs run #7: crashed: WARNING in corrupted run #8: crashed: WARNING in kcm_write_msgs run #9: crashed: WARNING in kcm_write_msgs testing release v4.18 testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.1.0 kernel signature: 59dee8c104429f4c1edf9b9b5b6d3dc66640fb34e51c890a90ec2031c64d214d all runs: crashed: WARNING in kcm_write_msgs testing release v4.17 testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.1.0 kernel signature: 5b791cdb1f2a6d48c781993f0db399c9fd04c3cab5166da2cdcc186208b91cac run #0: crashed: WARNING in kcm_write_msgs run #1: crashed: WARNING in kcm_write_msgs run #2: crashed: WARNING in kcm_write_msgs run #3: crashed: WARNING in kcm_write_msgs run #4: crashed: WARNING in kcm_write_msgs run #5: crashed: WARNING in kcm_write_msgs run #6: crashed: WARNING in kcm_write_msgs run #7: crashed: WARNING in corrupted run #8: crashed: WARNING in kcm_write_msgs run #9: crashed: WARNING in kcm_write_msgs testing release v4.16 testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.1.0 kernel signature: e557eb676940565ab3dd98808ecdca32f15a5d4a7d0768a467e6414723a2d31f all runs: crashed: WARNING in kcm_write_msgs testing release v4.15 testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.1.0 kernel signature: 3daaac390b2273d97384b209bc98af188af71f32149d735064a396a8e7c8f490 all runs: crashed: WARNING in kcm_write_msgs testing release v4.14 testing commit bebc6082da0a9f5d47a1ea2edc099bf671058bd4 with gcc (GCC) 8.1.0 kernel signature: 262c8b82f219f3cacdeb85c0f11fb7a745c6ee99a38419875f74df819e832322 all runs: crashed: WARNING in kcm_write_msgs testing release v4.13 testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.1.0 kernel signature: 9cc90b079c681ce9b9999803cd7a0d6ffabddd50957f1c3e9f958cb776bf0fbc run #0: crashed: WARNING in kcm_write_msgs run #1: crashed: WARNING in kcm_write_msgs run #2: crashed: WARNING in corrupted run #3: crashed: WARNING in kcm_write_msgs run #4: crashed: WARNING in kcm_write_msgs run #5: crashed: WARNING in kcm_write_msgs run #6: crashed: WARNING in kcm_write_msgs run #7: crashed: WARNING in kcm_write_msgs run #8: crashed: WARNING in kcm_write_msgs run #9: crashed: WARNING in kcm_write_msgs testing release v4.12 testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.1.0 kernel signature: c69d51a212ffe6b45380d8a2da54e5b996a599d2dd2b1ba5853dbf425a9b42f8 run #0: crashed: BUG: sleeping function called from invalid context in tap_get_minor run #1: crashed: BUG: sleeping function called from invalid context in tap_get_minor run #2: crashed: BUG: sleeping function called from invalid context in tap_get_minor run #3: crashed: BUG: sleeping function called from invalid context in tap_get_minor run #4: crashed: BUG: sleeping function called from invalid context in tap_get_minor run #5: crashed: BUG: sleeping function called from invalid context in tap_get_minor run #6: crashed: BUG: sleeping function called from invalid context in tap_get_minor run #7: crashed: BUG: sleeping function called from invalid context in tap_get_minor run #8: crashed: BUG: sleeping function called from invalid context in tap_get_minor run #9: boot failed: WARNING: kernel stack regs has bad 'bp' value testing release v4.11 testing commit a351e9b9fc24e982ec2f0e76379a49826036da12 with gcc (GCC) 7.3.0 kernel signature: ae3be40d5458f4a6c300d35bf8893b1330813437936b56a4753234a48ebbb709 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: 05bab0a37de10c35fc77b93bb211e51d6fcac7274178b8daf297204fc81f14a4 all runs: crashed: WARNING in kcm_write_msgs testing release v4.9 testing commit 69973b830859bc6529a7a0468ba0d80ee5117826 with gcc (GCC) 5.5.0 kernel signature: 8faaeedec54965dacf2d6b5d3a6a54ba1bc462793832afc234d06d772a89a999 all runs: crashed: WARNING in kcm_write_msgs testing release v4.8 testing commit c8d2bc9bc39ebea8437fd974fdbc21847bb897a3 with gcc (GCC) 5.5.0 kernel signature: e30f68775acff63c52b029016e6e88ac825aba975ff0eb5f73048951dda6271a all runs: crashed: WARNING in kcm_write_msgs testing release v4.7 testing commit 523d939ef98fd712632d93a5a2b588e477a7565e with gcc (GCC) 5.5.0 kernel signature: 730ed024b2062ed7627cff383f1564f579bd175d40db625b8b58324480e17efd all runs: crashed: WARNING in kcm_write_msgs testing release v4.6 testing commit 2dcd0af568b0cf583645c8a317dd12e344b1c72a with gcc (GCC) 5.5.0 kernel signature: c65d3a3397278aa38132efd5c731678c791523c284be4a09f368d032a7eed76b all runs: crashed: WARNING in sysfs_warn_dup revisions tested: 22, total time: 3h24m29.325020772s (build: 2h1m21.789237007s, test: 1h19m11.073746445s) the crash already happened on the oldest tested release commit msg: Linux 4.6 crash: WARNING in sysfs_warn_dup device bridge_slave_1 entered promiscuous mode IPv6: ADDRCONF(NETDEV_UP): bridge0: link is not ready 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 ------------[ cut here ]------------ WARNING: CPU: 1 PID: 5896 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: 5896 Comm: syz-executor.0 Not tainted 4.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 1ffffffff0d95756 ffff8800b2f1efb0 ffffffff82c74fc6 ffffffff85c81040 ffff8800b2f1f088 ffffffff85d2bac0 ffffffff81922ccb ffff8800b2f1f078 ffffffff8160cf4e 0000000041b58ab3 ffffffff868f1f61 ffffffff8160cd9f Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xe6/0x120 lib/dump_stack.c:51 [] ? sysfs_warn_dup+0x7b/0xa0 fs/sysfs/dir.c:30 [] panic+0x1af/0x348 kernel/panic.c:152 [] ? set_ti_thread_flag+0xf/0xf include/linux/thread_info.h:73 [] ? sysfs_warn_dup+0x7b/0xa0 fs/sysfs/dir.c:30 [] __warn+0x18d/0x1b0 kernel/panic.c:504 [] warn_slowpath_fmt+0x92/0xb0 kernel/panic.c:527 [] ? __warn+0x1b0/0x1b0 kernel/panic.c:494 [] ? spin_unlock_irqrestore include/linux/spinlock.h:362 [inline] [] ? kernfs_path_from_node+0x4a/0x60 fs/kernfs/dir.c:234 [] 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 [] ? kfree_const+0x1d/0x20 mm/util.c:35 [] ? device_private_init+0x180/0x180 drivers/base/core.c:996 [] ? kfree_const+0x1d/0x20 mm/util.c:35 [] ? kobject_set_name_vargs+0xb4/0x130 lib/kobject.c:285 [] 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 [] ? device_create_vargs+0x20/0x20 drivers/base/core.c:1751 [] ? macvlan_set_mac_address+0x150/0x150 drivers/net/macvlan.c:697 [] 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 [] ? netdev_change_features+0x80/0x80 net/core/dev.c:6801 [] ? dev_get_nest_level+0x10c/0x1a0 net/core/dev.c:5974 [] macvlan_common_newlink+0x8b9/0x1090 drivers/net/macvlan.c:1316 [] macvtap_newlink+0xbf/0x110 drivers/net/macvtap.c:471 [] ? __netlink_ns_capable+0xc7/0xf0 net/netlink/af_netlink.c:783 [] rtnl_newlink+0xd4b/0x1230 net/core/rtnetlink.c:2466 [] ? rtnl_link_ops_get+0x5d/0x90 net/core/rtnetlink.c:284 [] ? rtnl_newlink+0x319/0x1230 net/core/rtnetlink.c:2322 [] ? debug_check_no_locks_freed+0x3c0/0x3c0 include/linux/sched.h:1954 [] ? rtnl_setlink+0x2f0/0x2f0 net/core/rtnetlink.c:2067 [] ? debug_lockdep_rcu_enabled+0x77/0x90 kernel/rcu/update.c:261 [] ? lookup_chain_cache kernel/locking/lockdep.c:2133 [inline] [] ? validate_chain kernel/locking/lockdep.c:2231 [inline] [] ? __lock_acquire+0x1985/0x5560 kernel/locking/lockdep.c:3329 [] ? __update_load_avg kernel/sched/fair.c:2716 [inline] [] ? update_cfs_rq_load_avg+0x511/0x1100 kernel/sched/fair.c:2843 [] ? debug_check_no_locks_freed+0x3c0/0x3c0 include/linux/sched.h:1954 [] ? __netlink_ns_capable+0xc7/0xf0 net/netlink/af_netlink.c:783 [] rtnetlink_rcv_msg+0x222/0x680 net/core/rtnetlink.c:3513 [] ? __trace_hardirqs_on_caller kernel/locking/lockdep.c:2680 [inline] [] ? trace_hardirqs_on_caller+0x44c/0x5e0 kernel/locking/lockdep.c:2727 [] ? rtnetlink_rcv+0x30/0x30 net/core/rtnetlink.c:3521 [] ? __mutex_lock_common kernel/locking/mutex.c:601 [inline] [] ? mutex_lock_nested+0x638/0xb30 kernel/locking/mutex.c:618 [] ? rtnl_lock net/core/rtnetlink.c:70 [inline] [] ? rtnetlink_rcv+0x16/0x30 net/core/rtnetlink.c:3518 [] ? rcu_read_lock include/linux/rcupdate.h:871 [inline] [] ? netlink_lookup+0xd4/0x630 net/netlink/af_netlink.c:457 [] netlink_rcv_skb+0x242/0x350 net/netlink/af_netlink.c:2277 [] ? rtnetlink_rcv+0x30/0x30 net/core/rtnetlink.c:3521 [] 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_deliver_tap_kernel net/netlink/af_netlink.c:275 [inline] [] ? netlink_unicast_kernel net/netlink/af_netlink.c:1213 [inline] [] ? netlink_unicast+0x3b5/0x660 net/netlink/af_netlink.c:1240 [] ? netlink_attachskb+0x730/0x730 include/linux/sched.h:2918 [] netlink_sendmsg+0x893/0xb40 net/netlink/af_netlink.c:1786 [] ? netlink_unicast+0x660/0x660 include/net/sock.h:1975 [] ? __might_fault+0xf1/0x1b0 mm/memory.c:3876 [] ? netlink_unicast+0x660/0x660 include/net/sock.h:1975 [] sock_sendmsg_nosec net/socket.c:612 [inline] [] sock_sendmsg+0xb5/0xf0 net/socket.c:622 [] SYSC_sendto+0x1c9/0x300 net/socket.c:1648 [] ? SYSC_connect+0x2a0/0x2a0 net/socket.c:1540 [] ? rcu_read_unlock include/linux/rcupdate.h:922 [inline] [] ? mntput_no_expire+0xb1/0x600 fs/namespace.c:1095 [] ? rcu_lock_release include/linux/rcupdate.h:491 [inline] [] ? rcu_read_unlock include/linux/rcupdate.h:926 [inline] [] ? mntput_no_expire+0xce/0x600 fs/namespace.c:1095 [] ? mnt_get_count+0x1c0/0x1c0 fs/namespace.c:184 [] ? mntput+0x52/0x70 fs/namespace.c:1143 [] ? ___might_sleep+0x331/0x440 kernel/sched/core.c:7435 [] ? __trace_hardirqs_on_caller kernel/locking/lockdep.c:2680 [inline] [] ? trace_hardirqs_on_caller+0x44c/0x5e0 kernel/locking/lockdep.c:2727 [] ? trace_hardirqs_on_thunk+0x1b/0x1d [] SyS_sendto+0x9/0x10 net/socket.c:1616 [] entry_SYSCALL_64_fastpath+0x23/0xc1 Kernel Offset: disabled