bisecting cause commit starting from acf25aa66371359f542d14e8d993b530fe25d7ac
building syzkaller on 6720fdefa085931a94cd81c6e097a59af54d362d
testing commit acf25aa66371359f542d14e8d993b530fe25d7ac with gcc (GCC) 8.1.0
kernel signature: d4cd749b94354f623c85747c4d6a8e49f690030fd3eadbfc8577f5dbf881d43c
all runs: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v5.7
testing commit 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162 with gcc (GCC) 8.1.0
kernel signature: a7298b4d4d54244921bb1611e646e886890fc0ca1bc1a4816cf0a13eb83822f3
run #0: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #1: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #2: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #3: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #4: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #5: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #6: crashed: KASAN: use-after-free Read in relabel_self_seq_show
run #7: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #8: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #9: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v5.6
testing commit 7111951b8d4973bda27ff663f2cf18b663d15b48 with gcc (GCC) 8.1.0
kernel signature: 689281d56c085a38d4a174943c9396e1b6a9b873194b24a2db0a051f6fbaf003
run #0: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #1: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #2: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #3: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #4: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #5: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #6: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #7: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #8: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #9: boot failed: can't ssh into the instance
testing release v5.5
testing commit d5226fa6dbae0569ee43ecfc08bdcd6770fc4755 with gcc (GCC) 8.1.0
kernel signature: 7b68d0946646a154988ddf4c00796ef6c2ac7310a28233325b8423a273b74b7c
all runs: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v5.4
testing commit 219d54332a09e8d8741c1e1982f5eae56099de85 with gcc (GCC) 8.1.0
kernel signature: 2e9372d3aeb06a0c8caf899f0c9ddbc0d4ff95bad7466120183db7b30d431b73
run #0: crashed: KASAN: use-after-free Read in relabel_self_seq_show
run #1: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #2: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #3: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #4: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #5: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #6: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #7: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #8: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #9: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v5.3
testing commit 4d856f72c10ecb060868ed10ff1b1453943fc6c8 with gcc (GCC) 8.1.0
kernel signature: bf5f79144a4379d1edeb1c97dd0f79e15f81b45cdf9d9932824f12832cae01c2
run #0: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #1: crashed: KASAN: use-after-free Read in relabel_self_seq_show
run #2: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #3: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #4: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #5: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #6: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #7: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #8: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #9: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v5.2
testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.1.0
kernel signature: 83ae1a4dcc85389447cdd0053039e6fa22eedb3656f7d0af2756f2b836c99331
all runs: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v5.1
testing commit e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd with gcc (GCC) 8.1.0
kernel signature: c1f4ae0c31c41831dd7d3343a038d27aaddd4607ee18b424d94705f22bee8023
all runs: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v5.0
testing commit 1c163f4c7b3f621efff9b28a47abb36f7378d783 with gcc (GCC) 8.1.0
kernel signature: 7956569410bf7a499457ee0354c6a4b9cef7bee662fd933ca611086664ddd2c4
all runs: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v4.20
testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.1.0
kernel signature: 9cd4162c179c894d5fad522f98ca7d707874808b606d20eb01f92048688de546
run #0: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #1: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #2: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #3: crashed: KASAN: use-after-free Read in relabel_self_seq_show
run #4: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #5: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #6: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #7: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #8: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #9: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v4.19
testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.1.0
kernel signature: 850f2a5a1b8c0099cca4e9ae9ca2ea9d406c72fb31dbc51bf4b11b4b5917b06f
all runs: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v4.18
testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.1.0
kernel signature: 98a55aace9946197fd03529bda0225d13f572a3e38518bae573f8919a3abfd39
all runs: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v4.17
testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.1.0
kernel signature: 02f02e7ec3bb9850c83ee9d17f32b023b8bbc1bca6799df3d43ded459c855246
run #0: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #1: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #2: crashed: KASAN: use-after-free Read in relabel_self_seq_show
run #3: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #4: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #5: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #6: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #7: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #8: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #9: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v4.16
testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.1.0
kernel signature: dc90d986bd7f90aca315e8525ec3e01fbd1d50b354b018902deac9e55fa90114
all runs: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v4.15
testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.1.0
kernel signature: d1af9bce0f0a8fcb650e5c79794fb4a85e73f989745c832b2ffcc89c527c43c5
run #0: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #1: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #2: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #3: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #4: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #5: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #6: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #7: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #8: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #9: crashed: KASAN: use-after-free Read in relabel_self_seq_show
testing release v4.14
testing commit bebc6082da0a9f5d47a1ea2edc099bf671058bd4 with gcc (GCC) 8.1.0
kernel signature: 0a2f63bff7aa35d23cf3103eccfab8a4732b62573e1747d7bf461ae540a5015a
run #0: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #1: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #2: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #3: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #4: crashed: KASAN: use-after-free Read in relabel_self_seq_show
run #5: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #6: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #7: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #8: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #9: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v4.13
testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.1.0
kernel signature: d31b001175024cfb318e400b01fa9f4e5f32a8b860f17bfcb6dd5eb0255d62b3
all runs: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v4.12
testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.1.0
kernel signature: 1c8166eab43c9fd376c7fb7f46d12b1d6b48ae82298bc57fbd24222ec2ba5205
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: ef627296355f82eee186bc440eef32503d872cecb60a4e966e0f9d91dd18d1cf
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: fbe4b30ec2fa1db620e06c28c137600f30886c8bf1da128157a91de0045f48fd
all runs: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v4.9
testing commit 69973b830859bc6529a7a0468ba0d80ee5117826 with gcc (GCC) 5.5.0
kernel signature: af69b333cc68506ba921a3448d0779fbd017d63e9f6e4d097aea38283ea81d5d
run #0: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #1: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #2: crashed: BUG: Double free or freeing an invalid pointer
run #3: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #4: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #5: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #6: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #7: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #8: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #9: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v4.8
testing commit c8d2bc9bc39ebea8437fd974fdbc21847bb897a3 with gcc (GCC) 5.5.0
kernel signature: 1049fe38f1e2e5951a57915ccd38e92a1a63b54204e174494540eb0a1249e9fe
run #0: crashed: BUG: Double free or freeing an invalid pointer
run #1: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #2: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #3: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #4: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #5: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #6: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #7: crashed: KASAN: use-after-free in smk_write_relabel_self at addr ADDR
run #8: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #9: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v4.7
testing commit 523d939ef98fd712632d93a5a2b588e477a7565e with gcc (GCC) 5.5.0
kernel signature: b6bc9a746c4cb1088743e7ea62137d7d72cfe3e48b0346e54c9cb2d26fc03054
run #0: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #1: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #2: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #3: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #4: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #5: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #6: crashed: KASAN: use-after-free in relabel_self_seq_show at addr ADDR
run #7: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #8: crashed: KASAN: use-after-free Read in smk_write_relabel_self
run #9: crashed: KASAN: use-after-free Read in smk_write_relabel_self
testing release v4.6
testing commit 2dcd0af568b0cf583645c8a317dd12e344b1c72a with gcc (GCC) 5.5.0
kernel signature: ea2471ad803ec7f4609b5788f9f232e08c51f5483580c78ac5bd545e72afd3d0
all runs: crashed: WARNING in sysfs_warn_dup
revisions tested: 24, total time: 3h47m11.159686117s (build: 2h16m26.382366281s, test: 1h28m3.061267907s)
the crash already happened on the oldest tested release
commit msg: Linux 4.6
crash: WARNING in sysfs_warn_dup
bridge0: port 2(bridge_slave_1) entered disabled state
device bridge_slave_1 entered promiscuous mode
IPv6: ADDRCONF(NETDEV_UP): bridge_slave_0: link is not ready
IPv6: ADDRCONF(NETDEV_UP): bridge_slave_1: link is not ready
------------[ cut here ]------------
WARNING: CPU: 1 PID: 5879 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: 5879 Comm: syz-executor.3 Not tainted 4.6.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 ffff8800b10befc8 ffffffff82c65e52 ffffffff85c81040
 ffff8800b10bf0a0 ffffffff85d2bb80 ffffffff8191bd7b 0000000000000009
 ffff8800b10bf090 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