bisecting cause commit starting from 583090b1b8232e6eae243a9009699666153a13a9 building syzkaller on d81b165e87aa21172574c227b0808df2957e29ce testing commit 583090b1b8232e6eae243a9009699666153a13a9 with gcc (GCC) 8.1.0 kernel signature: e1de29f92ee3569bb9eeb47af7f624faaadd0c3b63f10b8b5e896dd24f5b55db all runs: crashed: WARNING in drop_nlink testing release v5.8 testing commit bcf876870b95592b52519ed4aafcf9d95999bc9c with gcc (GCC) 8.1.0 kernel signature: f315225fd1f5bb998f0c900dcf805d9f8eb41d51aae024c979cf73ca6d6c2d72 run #0: crashed: WARNING in drop_nlink run #1: crashed: WARNING in drop_nlink run #2: crashed: WARNING in drop_nlink run #3: crashed: WARNING in drop_nlink run #4: crashed: WARNING in drop_nlink run #5: crashed: WARNING in drop_nlink run #6: crashed: WARNING in drop_nlink run #7: crashed: WARNING in drop_nlink run #8: crashed: WARNING in drop_nlink run #9: boot failed: can't ssh into the instance testing release v5.7 testing commit 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162 with gcc (GCC) 8.1.0 kernel signature: 47ad7326826fdd067a36435181b3a7a1dd811d8bf406f4da0536496aa67cb0b8 all runs: crashed: WARNING in drop_nlink testing release v5.6 testing commit 7111951b8d4973bda27ff663f2cf18b663d15b48 with gcc (GCC) 8.1.0 kernel signature: 5ab0523fd24c58710dbf9b2c05b9daa63788c77c81d73a7e441bdc694ea1640a all runs: crashed: WARNING in drop_nlink testing release v5.5 testing commit d5226fa6dbae0569ee43ecfc08bdcd6770fc4755 with gcc (GCC) 8.1.0 kernel signature: 94be2cc7352402f9ec3ad3e1721e9e6ffc7bb88bd36a7669a7011adbe5dcef2d all runs: crashed: WARNING in drop_nlink testing release v5.4 testing commit 219d54332a09e8d8741c1e1982f5eae56099de85 with gcc (GCC) 8.1.0 kernel signature: 70afdb7684a1940c1e9a4602172e41b0c0b4cce06fa8f1630cc21b3161f9d27e all runs: crashed: WARNING in drop_nlink testing release v5.3 testing commit 4d856f72c10ecb060868ed10ff1b1453943fc6c8 with gcc (GCC) 8.1.0 kernel signature: ba46d8efc9665134496cd6b08e9ed492c1358f98241561d0a50839edc81ca2df all runs: crashed: WARNING in drop_nlink testing release v5.2 testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.1.0 kernel signature: fa337679552a5dab0a3e74f9a0b689ab1a851b7cbc5725fcd8373c79e17ceb77 all runs: crashed: WARNING in drop_nlink testing release v5.1 testing commit e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd with gcc (GCC) 8.1.0 kernel signature: eb86e4441bcba6e5ff2ac8471765599344308e1e02321117b802fa4837098332 all runs: crashed: WARNING in drop_nlink testing release v5.0 testing commit 1c163f4c7b3f621efff9b28a47abb36f7378d783 with gcc (GCC) 8.1.0 kernel signature: 879d154a3b55604e7f81bc91e0cfe8d8a77ca80578df922f4fd54bcc58c1ceed all runs: crashed: WARNING in drop_nlink testing release v4.20 testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.1.0 kernel signature: 76642278eb3ce6001eb5f35f4298a149c5281ff2ce0aa95b96639bba42789bce run #0: crashed: WARNING in drop_nlink run #1: crashed: WARNING in drop_nlink run #2: crashed: WARNING in drop_nlink run #3: crashed: WARNING in drop_nlink run #4: crashed: WARNING in drop_nlink run #5: crashed: WARNING in drop_nlink run #6: crashed: WARNING in corrupted run #7: crashed: WARNING in drop_nlink run #8: crashed: WARNING in drop_nlink run #9: crashed: WARNING in drop_nlink testing release v4.19 testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.1.0 kernel signature: 129d47dcaef365ecb18482f8e2a1f0e50f0ed32d5e3a8687131ae1e2ccc51357 run #0: crashed: WARNING in drop_nlink run #1: crashed: WARNING in drop_nlink run #2: crashed: WARNING in corrupted run #3: crashed: WARNING in drop_nlink run #4: crashed: WARNING in drop_nlink run #5: crashed: WARNING in drop_nlink run #6: crashed: WARNING in drop_nlink run #7: crashed: WARNING in drop_nlink run #8: crashed: WARNING in drop_nlink run #9: crashed: WARNING in drop_nlink testing release v4.18 testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.1.0 kernel signature: 8c4a8613c95cfde99fde2b1bbad66c84eaa32fa24b7c3a0ad77c37051f8a2443 all runs: crashed: WARNING in drop_nlink testing release v4.17 testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.1.0 kernel signature: 3312bec5679fbaa5d1647fd75325a228bfed7337b87983f466be75980fa451a2 run #0: crashed: WARNING in drop_nlink run #1: crashed: WARNING in drop_nlink run #2: crashed: WARNING in drop_nlink run #3: crashed: WARNING in drop_nlink run #4: crashed: WARNING in corrupted run #5: crashed: WARNING in drop_nlink run #6: crashed: WARNING in drop_nlink run #7: crashed: WARNING in corrupted run #8: crashed: WARNING in drop_nlink run #9: crashed: WARNING in drop_nlink testing release v4.16 testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.1.0 kernel signature: 73952102bbcfd96574e61650e0b9056aaf7f9f2e56035704ad26d6078567439c all runs: crashed: WARNING in drop_nlink testing release v4.15 testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.1.0 kernel signature: 734f144f9db19f2c2a5305c8bf420c656476f5695bd81b066e05b225e57049c3 all runs: crashed: WARNING in drop_nlink testing release v4.14 testing commit bebc6082da0a9f5d47a1ea2edc099bf671058bd4 with gcc (GCC) 8.1.0 kernel signature: 2d692cb0a8b21308119d7584df2cc36d48f6bc08c89933376773b585a077c4eb all runs: crashed: WARNING in drop_nlink testing release v4.13 testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.1.0 kernel signature: a17217789d633b2cbcbcb3bfe37663fcb06855f77fa7dae0a11d5c3e1518c1f7 all runs: crashed: WARNING in drop_nlink testing release v4.12 testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.1.0 kernel signature: cbc8b138fe515ce2df4848d139b6cd9d35e7dc076acc28973487276a2c22fd57 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: a92fab16959275fe571add0701d66068856b6299747843ba534fabc11e7c6d09 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: de2fe9ab6a9d46c1aef7dcbdd90fcd58efd8ad2183f397fba662b923e18f9ae7 all runs: crashed: WARNING in drop_nlink testing release v4.9 testing commit 69973b830859bc6529a7a0468ba0d80ee5117826 with gcc (GCC) 5.5.0 kernel signature: 222e423cdeff92c048179b134b3b5b1be1b78dd6f3b26f355dac9e5a08edf209 run #0: crashed: WARNING in drop_nlink run #1: crashed: WARNING in drop_nlink run #2: crashed: WARNING in drop_nlink run #3: crashed: WARNING in drop_nlink run #4: crashed: WARNING in drop_nlink run #5: crashed: WARNING in drop_nlink run #6: crashed: WARNING in corrupted run #7: crashed: WARNING in drop_nlink run #8: crashed: WARNING in drop_nlink run #9: crashed: WARNING in drop_nlink testing release v4.8 testing commit c8d2bc9bc39ebea8437fd974fdbc21847bb897a3 with gcc (GCC) 5.5.0 kernel signature: dcdb42a165560e728b0aa2309ef36f3b166ac0e88a383152ff3a0396008fbcaa all runs: crashed: WARNING in drop_nlink testing release v4.7 testing commit 523d939ef98fd712632d93a5a2b588e477a7565e with gcc (GCC) 5.5.0 kernel signature: 5dda05429ab82b6eda449d2a17612e05dc64dc55d2aab5a4e1725d679e6d7caf all runs: crashed: WARNING in drop_nlink testing release v4.6 testing commit 2dcd0af568b0cf583645c8a317dd12e344b1c72a with gcc (GCC) 5.5.0 kernel signature: 972c310359571291918d4e5a4521e72e1406e02e89ed851988564a4fc89f5fb7 all runs: crashed: WARNING in sysfs_warn_dup revisions tested: 25, total time: 3h59m36.795514788s (build: 2h22m28.177233605s, test: 1h33m7.013618319s) 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): hsr_slave_1: link is not ready bond0: Enslaving bond_slave_1 as an active interface with an up link ------------[ cut here ]------------ WARNING: CPU: 1 PID: 5915 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: 5915 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 ffff880000076fc8 ffffffff82e18b12 ffffffff85e81040 ffff8800000770a0 ffffffff85f2bc00 ffffffff8191bd7b 0000000000000009 ffff880000077090 ffffffff8160d884 0000000041b58ab3 ffffffff86b4158a 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