bisecting cause commit starting from 7cc2a8ea104820dd9e702202621e8fd4d9f6c8cf
building syzkaller on 510951950dc0ee69cfdaf746061d3dbe31b49fd8
testing commit 7cc2a8ea104820dd9e702202621e8fd4d9f6c8cf with gcc (GCC) 8.1.0
kernel signature: 6ae1c3c9f146504e961f63b1174a167748862592d54934ed9641a56931400229
run #0: crashed: INFO: rcu detected stall in sys_mount
run #1: crashed: INFO: rcu detected stall in corrupted
run #2: crashed: INFO: rcu detected stall in do_signal
run #3: crashed: INFO: rcu detected stall in corrupted
run #4: crashed: INFO: rcu detected stall in corrupted
run #5: crashed: INFO: task hung in lru_add_drain_all
run #6: crashed: INFO: task hung in lru_add_drain_all
run #7: crashed: INFO: task hung in lru_add_drain_all
run #8: crashed: BUG: workqueue lockup
run #9: OK
testing release v5.7
testing commit 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162 with gcc (GCC) 8.1.0
kernel signature: e9dbe06acf8d3a6766361171e713d3c3b405e31150425fa3cefde6e4277682e2
run #0: crashed: INFO: task hung in synchronize_rcu
run #1: crashed: BUG: workqueue lockup
run #2: crashed: BUG: workqueue lockup
run #3: crashed: INFO: rcu detected stall in sys_mount
run #4: crashed: INFO: task hung in process_one_work
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
testing release v5.6
testing commit 7111951b8d4973bda27ff663f2cf18b663d15b48 with gcc (GCC) 8.1.0
kernel signature: 9400c10fd50356daa5d77740f9b1a591ba49f9c137a96d79232a67e5759ebf97
run #0: crashed: INFO: rcu detected stall in corrupted
run #1: crashed: BUG: workqueue lockup
run #2: crashed: BUG: workqueue lockup
run #3: crashed: INFO: rcu detected stall in sys_mount
run #4: crashed: INFO: rcu detected stall in sys_mount
run #5: crashed: INFO: task hung in switchdev_deferred_process_work
run #6: crashed: INFO: task hung in linkwatch_event
run #7: crashed: BUG: workqueue lockup
run #8: OK
run #9: OK
testing release v5.5
testing commit d5226fa6dbae0569ee43ecfc08bdcd6770fc4755 with gcc (GCC) 8.1.0
kernel signature: d6f94a4854f8c2fc2e9ac7466bd2cd06d33e19ea30656d9fbde30517fd109c36
run #0: crashed: BUG: workqueue lockup
run #1: crashed: BUG: workqueue lockup
run #2: crashed: INFO: rcu detected stall in do_signal
run #3: crashed: INFO: rcu detected stall in sys_mount
run #4: crashed: INFO: rcu detected stall in force_sig_fault
run #5: crashed: INFO: rcu detected stall in sys_mount
run #6: OK
run #7: OK
run #8: OK
run #9: OK
testing release v5.4
testing commit 219d54332a09e8d8741c1e1982f5eae56099de85 with gcc (GCC) 8.1.0
kernel signature: 0944ddf70245afdc27d4a79a255bd4f4746888634663bf020ee9ff5f7041bed4
run #0: crashed: INFO: rcu detected stall in __do_page_fault
run #1: crashed: BUG: workqueue lockup
run #2: crashed: BUG: workqueue lockup
run #3: crashed: INFO: task hung in switchdev_deferred_process_work
run #4: crashed: INFO: task hung in linkwatch_event
run #5: crashed: BUG: workqueue lockup
run #6: OK
run #7: OK
run #8: OK
run #9: OK
testing release v5.3
testing commit 4d856f72c10ecb060868ed10ff1b1453943fc6c8 with gcc (GCC) 8.1.0
kernel signature: ba686efe134d439f2a03ecb108fb43505631a7d17eb1d685334d0e6f903dc176
run #0: crashed: INFO: rcu detected stall in sys_mount
run #1: crashed: INFO: rcu detected stall in __do_page_fault
run #2: crashed: INFO: rcu detected stall in sys_mount
run #3: crashed: INFO: rcu detected stall in sys_mount
run #4: crashed: INFO: rcu detected stall in sys_mount
run #5: crashed: BUG: workqueue lockup
run #6: crashed: BUG: workqueue lockup
run #7: crashed: BUG: workqueue lockup
run #8: OK
run #9: OK
testing release v5.2
testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.1.0
kernel signature: 569df87cffdce0ec8597d4c9764a851f3df49a57091d3ef00da7cad64d4d6858
run #0: crashed: INFO: rcu detected stall in sys_mount
run #1: crashed: INFO: rcu detected stall in sys_mount
run #2: crashed: INFO: rcu detected stall in do_signal
run #3: crashed: INFO: rcu detected stall in sys_mount
run #4: crashed: BUG: workqueue lockup
run #5: crashed: BUG: workqueue lockup
run #6: crashed: BUG: workqueue lockup
run #7: crashed: INFO: rcu detected stall in bad_area
run #8: crashed: INFO: rcu detected stall in bad_area
run #9: OK
testing release v5.1
testing commit e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd with gcc (GCC) 8.1.0
kernel signature: 5d2593882b56deacc86d3e5f8aa1862e650de6ca9fc9e85ef1007e9ebcedb1f8
run #0: crashed: INFO: rcu detected stall in do_signal
run #1: crashed: INFO: rcu detected stall in do_signal
run #2: crashed: INFO: task hung in synchronize_rcu
run #3: crashed: INFO: rcu detected stall in do_signal
run #4: crashed: BUG: workqueue lockup
run #5: crashed: INFO: rcu detected stall in do_signal
run #6: crashed: BUG: workqueue lockup
run #7: OK
run #8: OK
run #9: OK
testing release v5.0
testing commit 1c163f4c7b3f621efff9b28a47abb36f7378d783 with gcc (GCC) 8.1.0
kernel signature: 82679dad3d6129403fac0b30202700350906ce38034f1658c04db83ab9b84368
run #0: crashed: INFO: rcu detected stall in sys_mount
run #1: crashed: INFO: rcu detected stall in sys_mount
run #2: crashed: INFO: rcu detected stall in sys_mount
run #3: crashed: INFO: rcu detected stall in sys_mount
run #4: crashed: INFO: rcu detected stall in sys_mount
run #5: crashed: BUG: workqueue lockup
run #6: OK
run #7: OK
run #8: OK
run #9: OK
testing release v4.20
testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.1.0
kernel signature: 56af92a4a9da50d521108aa07eab1808ce922e7ec68816bc3ec3ad1aee74f006
run #0: crashed: INFO: rcu detected stall in sys_mount
run #1: crashed: INFO: rcu detected stall in sys_mount
run #2: crashed: INFO: rcu detected stall in sys_mount
run #3: crashed: INFO: rcu detected stall in sys_mount
run #4: crashed: INFO: rcu detected stall in sys_mount
run #5: crashed: INFO: rcu detected stall in lock_is_held_type
run #6: crashed: INFO: rcu detected stall in sys_mount
run #7: crashed: INFO: rcu detected stall in do_signal
run #8: crashed: BUG: workqueue lockup
run #9: crashed: INFO: rcu detected stall in do_signal
testing release v4.19
testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.1.0
kernel signature: 222a7b7ad2ff40c72d49d79eacff47758d5a549b11b52cfb9dea41e51692a12c
run #0: crashed: INFO: task hung in synchronize_rcu
run #1: crashed: INFO: task hung in synchronize_rcu
run #2: crashed: INFO: task hung in synchronize_rcu
run #3: crashed: BUG: workqueue lockup
run #4: crashed: BUG: workqueue lockup
run #5: crashed: BUG: workqueue lockup
run #6: crashed: no output from test machine
run #7: OK
run #8: OK
run #9: OK
testing release v4.18
testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.1.0
kernel signature: 0fb1b7453b0600480d4dcaf34294fb8610914323a6742bd2047c8630119da0be
run #0: crashed: INFO: task hung in synchronize_rcu
run #1: crashed: INFO: task hung in synchronize_rcu
run #2: crashed: INFO: task hung in synchronize_rcu
run #3: crashed: BUG: workqueue lockup
run #4: crashed: INFO: task hung in synchronize_rcu
run #5: crashed: BUG: workqueue lockup
run #6: OK
run #7: OK
run #8: OK
run #9: OK
testing release v4.17
testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.1.0
kernel signature: 37e9668f5e43444c427411ebf4e1674835ca0b975c495db33b473c54e0f692ac
run #0: crashed: INFO: task hung in synchronize_rcu
run #1: crashed: INFO: task hung in synchronize_rcu
run #2: crashed: INFO: task hung in synchronize_rcu
run #3: crashed: INFO: task hung in synchronize_rcu
run #4: crashed: BUG: workqueue lockup
run #5: crashed: BUG: workqueue lockup
run #6: OK
run #7: OK
run #8: crashed: BUG: workqueue lockup
run #9: OK
testing release v4.16
testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.1.0
kernel signature: fc4ca46391217ffc48d53e0a13b71dd8225316d49a7ad456e3be0f539217cc20
run #0: crashed: INFO: task hung in synchronize_rcu
run #1: crashed: BUG: workqueue lockup
run #2: crashed: INFO: task hung in blk_freeze_queue
run #3: crashed: INFO: task hung in synchronize_rcu
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
testing release v4.15
testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.1.0
kernel signature: b9a2836572e14738b748bca160016cc4f07df1dc5f5efa4fc99b3afb52893e11
run #0: crashed: BUG: workqueue lockup
run #1: crashed: BUG: workqueue lockup
run #2: crashed: INFO: task hung in synchronize_rcu
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
testing release v4.14
testing commit bebc6082da0a9f5d47a1ea2edc099bf671058bd4 with gcc (GCC) 8.1.0
kernel signature: 54850b4a1abf335279cb59f23bd7b98ab82a08e6bdc134ef5b1ea4660d9c412f
run #0: crashed: INFO: task hung in ext4_find_entry
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
testing release v4.13
testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.1.0
kernel signature: ad7bd6d970fd98691837773df7b7cf2324abaf6bbe4b62114a7d2aa82aa86e52
run #0: crashed: INFO: task hung in synchronize_rcu
run #1: crashed: INFO: task hung in synchronize_rcu
run #2: crashed: INFO: task hung in synchronize_rcu
run #3: crashed: INFO: task hung in ext4_find_entry
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
testing release v4.12
testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.1.0
kernel signature: 81d3b8f4b05cb9949d6d2ea7af10755672740c27811823d5e925274a095520af
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: 1ff5ad99c858fafc0ff375b07787423ccb9a765cee7aaeefb9bd96395a0b0b3c
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: 0ecb407329a7f2f542729552674d41ecbfa66be72718d1ae71a4ed94faf64af8
run #0: crashed: INFO: task hung in synchronize_rcu
run #1: crashed: BUG: workqueue lockup
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
testing release v4.9
testing commit 69973b830859bc6529a7a0468ba0d80ee5117826 with gcc (GCC) 5.5.0
kernel signature: a2b1feb2218c464cc8c462abb7c3041cddb9627633d20f7f3488c91f13885873
run #0: crashed: no output from test machine
run #1: crashed: BUG: workqueue lockup
run #2: crashed: INFO: task hung in copy_net_ns
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
testing release v4.8
testing commit c8d2bc9bc39ebea8437fd974fdbc21847bb897a3 with gcc (GCC) 5.5.0
kernel signature: d1ae0da3e3d03602bb3c1e5cbfaa33118569d96a899b12eb751794b938002bf7
run #0: crashed: BUG: workqueue lockup
run #1: crashed: BUG: workqueue lockup
run #2: crashed: BUG: workqueue lockup
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
testing release v4.7
testing commit 523d939ef98fd712632d93a5a2b588e477a7565e with gcc (GCC) 5.5.0
kernel signature: 750087894555d697b896353c0bd9adba18b434bc1bf32ba51aedd5f4bdfbfcc6
run #0: crashed: BUG: workqueue lockup
run #1: crashed: BUG: workqueue lockup
run #2: crashed: BUG: workqueue lockup
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
testing release v4.6
testing commit 2dcd0af568b0cf583645c8a317dd12e344b1c72a with gcc (GCC) 5.5.0
kernel signature: 2093c0e35bab6559befa0e3dd9a01b5892538d85afdf8e20ce3f8ee1c10a8f53
all runs: crashed: WARNING in sysfs_warn_dup
revisions tested: 24, total time: 5h54m42.515673682s (build: 2h14m42.975250574s, test: 3h35m4.298449422s)
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_0: link is not ready
------------[ cut here ]------------
WARNING: CPU: 1 PID: 5871 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: 5871 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
 0000000000000000 ffff880128fe6fc8 ffffffff82c65e52 ffffffff85c81040
 ffff880128fe70a0 ffffffff85d2bb80 ffffffff8191bd7b 0000000000000009
 ffff880128fe7090 ffffffff8160d884 0000000041b58ab3 ffffffff868f05e2
Call Trace:
 [<ffffffff82c65e52>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff82c65e52>] dump_stack+0x136/0x1d4 lib/dump_stack.c:51
 [<ffffffff8160d884>] panic+0x1af/0x348 kernel/panic.c:152
 [<ffffffff81335ecd>] __warn+0x18d/0x1b0 kernel/panic.c:504
 [<ffffffff81335f82>] warn_slowpath_fmt+0x92/0xb0 kernel/panic.c:527
 [<ffffffff8191bd7b>] sysfs_warn_dup+0x7b/0xa0 fs/sysfs/dir.c:30
 [<ffffffff8191c5f1>] sysfs_do_create_link_sd.isra.0+0xd1/0xf0 fs/sysfs/symlink.c:51
 [<ffffffff8191c653>] sysfs_do_create_link fs/sysfs/symlink.c:80 [inline]
 [<ffffffff8191c653>] sysfs_create_link+0x43/0xb0 fs/sysfs/symlink.c:92
 [<ffffffff83530677>] device_add_class_symlinks drivers/base/core.c:891 [inline]
 [<ffffffff83530677>] device_add+0x677/0x1350 drivers/base/core.c:1086
 [<ffffffff835316b8>] device_create_groups_vargs+0x1c8/0x220 drivers/base/core.c:1709
 [<ffffffff835317b8>] device_create_vargs drivers/base/core.c:1749 [inline]
 [<ffffffff835317b8>] device_create+0x88/0xa0 drivers/base/core.c:1785
 [<ffffffff838d0aa4>] macvtap_device_event+0x1c4/0x2a0 drivers/net/macvtap.c:1298
 [<ffffffff81399feb>] notifier_call_chain+0x8b/0x170 kernel/notifier.c:93
 [<ffffffff8139a0f1>] __raw_notifier_call_chain kernel/notifier.c:394 [inline]
 [<ffffffff8139a0f1>] raw_notifier_call_chain+0x11/0x20 kernel/notifier.c:401
 [<ffffffff84920ba7>] call_netdevice_notifiers_info+0x47/0x80 net/core/dev.c:1643
 [<ffffffff849455f8>] call_netdevice_notifiers net/core/dev.c:1659 [inline]
 [<ffffffff849455f8>] register_netdevice+0x8e8/0xd00 net/core/dev.c:7027
 [<ffffffff838c81f9>] macvlan_common_newlink+0x8b9/0x1090 drivers/net/macvlan.c:1316
 [<ffffffff838cee6f>] macvtap_newlink+0xbf/0x110 drivers/net/macvtap.c:471
 [<ffffffff849760ab>] rtnl_newlink+0xd4b/0x1230 net/core/rtnetlink.c:2466
 [<ffffffff84970b52>] rtnetlink_rcv_msg+0x222/0x680 net/core/rtnetlink.c:3513
 [<ffffffff84af4172>] netlink_rcv_skb+0x242/0x350 net/netlink/af_netlink.c:2277
 [<ffffffff84970925>] rtnetlink_rcv+0x25/0x30 net/core/rtnetlink.c:3519
 [<ffffffff84af2d0a>] netlink_unicast_kernel net/netlink/af_netlink.c:1214 [inline]
 [<ffffffff84af2d0a>] netlink_unicast+0x3da/0x560 net/netlink/af_netlink.c:1240
 [<ffffffff84af393b>] netlink_sendmsg+0x9bb/0xb40 net/netlink/af_netlink.c:1786
 [<ffffffff848cfe35>] sock_sendmsg_nosec net/socket.c:612 [inline]
 [<ffffffff848cfe35>] sock_sendmsg+0xb5/0xf0 net/socket.c:622
 [<ffffffff848d3c2a>] SYSC_sendto net/socket.c:1648 [inline]
 [<ffffffff848d3c2a>] SyS_sendto+0x1ca/0x290 net/socket.c:1616
 [<ffffffff85b70c40>] entry_SYSCALL_64_fastpath+0x23/0xc1
Kernel Offset: disabled