bisecting cause commit starting from 15ac8fdb74403772780be1a8c4f7c1eff1040fc4 building syzkaller on 51a9082e064119316893e12187cab2843283ed4d testing commit 15ac8fdb74403772780be1a8c4f7c1eff1040fc4 with gcc (GCC) 8.1.0 kernel signature: a7b140657b98ecf533a868ed61174dd64cd1d917d6d463dffbb1410e5df15ee3 all runs: crashed: UBSAN: shift-out-of-bounds in choke_enqueue testing release v5.9 testing commit bbf5c979011a099af5dc76498918ed7df445635b with gcc (GCC) 8.1.0 kernel signature: 0a239a63f936e094afcdc973a4a1640a49766a3338df273434ed919c9d53b108 all runs: crashed: UBSAN: shift-out-of-bounds in choke_enqueue testing release v5.8 testing commit bcf876870b95592b52519ed4aafcf9d95999bc9c with gcc (GCC) 8.1.0 kernel signature: 43a299fc537e8c714d4f291e0dd750ca62379f64f4e403b6386c91532496a188 all runs: crashed: UBSAN: shift-out-of-bounds in choke_enqueue testing release v5.7 testing commit 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162 with gcc (GCC) 8.1.0 kernel signature: 9d59fff760a571f9aef85675458244dad39af3409ec46744bf8b4640c1f90dc9 all runs: crashed: UBSAN: shift-out-of-bounds in choke_enqueue testing release v5.6 testing commit 7111951b8d4973bda27ff663f2cf18b663d15b48 with gcc (GCC) 8.1.0 kernel signature: 5a651a957f7b2d0a6c6a5e0d01901f2c562ec4a7117c85fb3ead69e0c7d7e9d0 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v5.5 testing commit d5226fa6dbae0569ee43ecfc08bdcd6770fc4755 with gcc (GCC) 8.1.0 kernel signature: 45db3359cea7d227a48aa67f77f64e309fe5579e273b03525727363462e79b2e run #0: crashed: KASAN: null-ptr-deref Write in choke_reset run #1: crashed: UBSAN: undefined-behaviour in choke_enqueue run #2: crashed: KASAN: null-ptr-deref Write in choke_reset run #3: crashed: KASAN: null-ptr-deref Write in choke_reset run #4: crashed: KASAN: null-ptr-deref Write in choke_reset run #5: crashed: KASAN: null-ptr-deref Write in choke_reset run #6: crashed: KASAN: null-ptr-deref Write in choke_reset run #7: crashed: KASAN: null-ptr-deref Write in choke_reset run #8: crashed: KASAN: null-ptr-deref Write in choke_reset run #9: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v5.4 testing commit 219d54332a09e8d8741c1e1982f5eae56099de85 with gcc (GCC) 8.1.0 kernel signature: 8c05250c5f3378271bc4a038b521dee136b4ac7982c41a849b91d0eb16099fa4 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v5.3 testing commit 4d856f72c10ecb060868ed10ff1b1453943fc6c8 with gcc (GCC) 8.1.0 kernel signature: 20ba57603f6377c5e073ce6a66b762e7782253146a352daa80104ec2b5a98d86 run #0: crashed: KASAN: null-ptr-deref Write in choke_reset run #1: crashed: KASAN: null-ptr-deref Write in choke_reset run #2: crashed: KASAN: null-ptr-deref Write in choke_reset run #3: crashed: KASAN: null-ptr-deref Write in choke_reset run #4: crashed: KASAN: null-ptr-deref Write in choke_reset run #5: crashed: KASAN: null-ptr-deref Write in choke_reset run #6: crashed: KASAN: null-ptr-deref Write in choke_reset run #7: crashed: KASAN: null-ptr-deref Write in choke_reset run #8: crashed: UBSAN: undefined-behaviour in choke_enqueue run #9: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v5.2 testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.1.0 kernel signature: 671d4b1d247e018930d04001b74feca42e2262a7ea06aaa729f3b7bbc46790d8 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v5.1 testing commit e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd with gcc (GCC) 8.1.0 kernel signature: c713242be38d96e897ea468e01561f06506deeaf2302297b1273b9d24d8d5bc6 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v5.0 testing commit 1c163f4c7b3f621efff9b28a47abb36f7378d783 with gcc (GCC) 8.1.0 kernel signature: 1e87b48aacdcb9ed6e0241257d28f1c16157b62d35c1755795f115d7e6331864 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v4.20 testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.1.0 kernel signature: 13e22def257966f5ac9bf6589075bb5e5b99f60740a323a9a41a968c1c769822 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v4.19 testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.1.0 kernel signature: 694d4e238370530a9fa4861b3891bba01bfb9164d9e925c21819f1e77611b738 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v4.18 testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.1.0 kernel signature: c4fd73cbb43a27406e33621b9145c5f5b28ce8b3bfa10b506a8f32eb1ce99300 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v4.17 testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.1.0 kernel signature: 608bd519efcf5452dc59116675b9bec4a57cc92f08c4578a1ea1dbb930d39d58 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v4.16 testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.1.0 kernel signature: 81a779943b2e4a808d7c169e0ce02f07087d665baef82da0d6302b0593eaab35 all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v4.15 testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.1.0 kernel signature: 37a68ed9caff0b903206ffa3a9511cf0dd2ded6ef61ef78ae5d06e3f1a208f0d all runs: crashed: KASAN: null-ptr-deref Write in choke_reset testing release v4.14 testing commit bebc6082da0a9f5d47a1ea2edc099bf671058bd4 with gcc (GCC) 8.1.0 kernel signature: fc8b307ce79cb99c1371fadb5078ab773ff8743cfef69242e794d726199de2dc all runs: crashed: divide error in choke_change testing release v4.13 testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.1.0 kernel signature: 4b7abeb566be13202b965986c085d7a089c869b19b7618eb62e3436aa67e7d90 all runs: crashed: divide error in choke_change testing release v4.12 testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.1.0 kernel signature: 5d01a1030aa518d4aedcac72ec3fa4ac869a85736b6cf308fdcd280ab0cd7e24 all runs: basic kernel testing failed: 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: bd7f75fa2e72a23e8a07c07641b66c16830f74475714d8ceac8815cfff67c6e4 all runs: basic kernel testing failed: 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: 3c497d36681cb8f1a5a14dfa5873ec33975463b542d8bf0ec66c0ffd417c302b all runs: crashed: divide error in choke_change testing release v4.9 testing commit 69973b830859bc6529a7a0468ba0d80ee5117826 with gcc (GCC) 5.5.0 kernel signature: 2285d19cd034433e6474612908f7adf985ee9607d72ff722b0c39d7c3e7e93c8 all runs: crashed: divide error in choke_change testing release v4.8 testing commit c8d2bc9bc39ebea8437fd974fdbc21847bb897a3 with gcc (GCC) 5.5.0 kernel signature: ac4777beca0870be2be3b3a85ea8941cfb68f398192bbb91a9bcba7c2b3e9417 all runs: crashed: divide error in choke_change testing release v4.7 testing commit 523d939ef98fd712632d93a5a2b588e477a7565e with gcc (GCC) 5.5.0 kernel signature: 1ee18b950f4209f04e29e08808f0fd74fa0f0c638872524a6733d9ab3acc722d all runs: crashed: divide error in choke_change testing release v4.6 testing commit 2dcd0af568b0cf583645c8a317dd12e344b1c72a with gcc (GCC) 5.5.0 kernel signature: dc2ed54bd3cea0a9411173f83d4cd0798a1c3905252201962484366f869943f8 all runs: crashed: WARNING in sysfs_warn_dup revisions tested: 26, total time: 3h20m30.902615445s (build: 2h4m41.560876274s, test: 1h11m49.044881934s) the crash already happened on the oldest tested release commit msg: Linux 4.6 crash: WARNING in sysfs_warn_dup IPv6: ADDRCONF(NETDEV_UP): bridge_slave_0: link is not ready 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 ------------[ cut here ]------------ WARNING: CPU: 1 PID: 7943 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: 7943 Comm: syz-executor.5 Not tainted 4.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 0000000000000000 ffff8800b1ae6fc8 ffffffff82dab352 ffffffff8667aec0 ffff8800b1ae70a0 ffffffff8672c8c0 ffffffff818db72b 0000000000000009 ffff8800b1ae7090 ffffffff815c7a54 0000000041b58ab3 ffffffff8778fdc3 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+0x6a1/0x1400 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