bisecting cause commit starting from 71c5f03154ac1cb27423b984743ccc2f5d11d14d building syzkaller on b982b3ea71acbb298ee60e06c9bdaca9f680125b testing commit 71c5f03154ac1cb27423b984743ccc2f5d11d14d with gcc (GCC) 8.1.0 kernel signature: 3bbb5fc1486d46328a2dddb7758de2fd86780a4a970e367441c4c41ca746134a all runs: crashed: UBSAN: shift-out-of-bounds in choke_change testing release v5.10 testing commit 2c85ebc57b3e1817b6ce1a6b703928e113a90442 with gcc (GCC) 8.1.0 kernel signature: f5760b2c445d15f5ece92b856df5a49be8c93d3d22f6cda3cb5ed85afe8f4ee1 all runs: crashed: UBSAN: shift-out-of-bounds in choke_change testing release v5.9 testing commit bbf5c979011a099af5dc76498918ed7df445635b with gcc (GCC) 8.1.0 kernel signature: 48a44b356059ba46606be11d05f4af2fd4977ae6064a111f191a24ab366037c1 all runs: crashed: UBSAN: shift-out-of-bounds in choke_change testing release v5.8 testing commit bcf876870b95592b52519ed4aafcf9d95999bc9c with gcc (GCC) 8.1.0 kernel signature: 22aa95b7e7e6aea83bcbde6ee96bb510036c390ecb1edc1d673d8134021fdfef run #0: crashed: UBSAN: shift-out-of-bounds in choke_change run #1: crashed: UBSAN: shift-out-of-bounds in choke_change run #2: crashed: UBSAN: shift-out-of-bounds in choke_change run #3: crashed: UBSAN: shift-out-of-bounds in choke_change run #4: crashed: UBSAN: shift-out-of-bounds in choke_change run #5: crashed: UBSAN: shift-out-of-bounds in choke_change run #6: crashed: UBSAN: shift-out-of-bounds in choke_change run #7: crashed: UBSAN: shift-out-of-bounds in choke_change run #8: crashed: UBSAN: shift-out-of-bounds in choke_change 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: f5d9faac2087b090050e744a65f37f315c08f987da9cd1b89f915d62396835a7 all runs: crashed: UBSAN: shift-out-of-bounds in choke_change testing release v5.6 testing commit 7111951b8d4973bda27ff663f2cf18b663d15b48 with gcc (GCC) 8.1.0 kernel signature: c44a15efe9f4dddfd3265e3ee72039e8fedc8e1a971752bf1b7899bdd24b69bf all runs: crashed: UBSAN: undefined-behaviour in choke_change testing release v5.5 testing commit d5226fa6dbae0569ee43ecfc08bdcd6770fc4755 with gcc (GCC) 8.1.0 kernel signature: 0965e741efe2c9a43f96ed4ce7756181094148b594e50125c1ef55585450eb5a all runs: crashed: UBSAN: undefined-behaviour in choke_change testing release v5.4 testing commit 219d54332a09e8d8741c1e1982f5eae56099de85 with gcc (GCC) 8.1.0 kernel signature: dc0e86cd1e84b0f0c4d2d664ac1a48c712bc8a201fcae8c2993a60e9b2ae998d all runs: crashed: UBSAN: undefined-behaviour in choke_change testing release v5.3 testing commit 4d856f72c10ecb060868ed10ff1b1453943fc6c8 with gcc (GCC) 8.1.0 kernel signature: b037b1dd21cfbbefec3369d9afc20b2628ba8eb7e83fdf09374888aacb7ba29f all runs: crashed: UBSAN: undefined-behaviour in choke_change testing release v5.2 testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.1.0 kernel signature: 93349bcc046589cc66751b3d8ad6ba9fb4ca2c06a1b85b534c498825df415deb 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: baae87b14f521b4d0298531dee49e0a8e580ad4914eded127bc80495085be314 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: 56e224fa321819c58e1b7f8aa075ac994eb8feafc73959952675898bf266d174 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: 821b77b904b90c5faad6d7b6c8b991ea6ab031b6d8779231322918f58f6a33bf 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: ce18a22144a609337c431f6bd13caf9d5e8ace5b95dfdb383afee31791db575d 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: 7aa30e15351ebaeda444abe1d66a04f415ac51b708c2b0a108b517c9bf06ac7f 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: ec37ae3c947b06b94954c6518e7b22058016cf6e7ca969f1b809a111697cce27 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: 5a2785fb1dcecb8182e0100c94eb104666bc6071d424ee1a1a4972a9d085915e 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: 8f9b45bf3484343f6d8f0c81e5fd72b67c804214ef01d7788f634a2b6ef1a44e 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: b948ae0df6beeabafc24f9f60c80ac01aeb3226316985b8c8efe7fe37f96ac1a all runs: crashed: divide error in choke_change testing release v4.13 testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.1.0 kernel signature: 03c85e1f8801324625ab20fd6a0ad87f38d3871161add658b08a15fa17634bfb all runs: crashed: divide error in choke_change testing release v4.12 testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.1.0 kernel signature: 5bac50cf2c332b2e7f1bf243d57782578bc8b7cb2824c58fa5db14d3464bd56c 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: e0eb621b9b95b50ee3d10608df2b13396da70927e44a57e231dc5f194de291fc 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: 4dc7b0b4e06def4e9b9fdaea1cf35e9105e09bf1490541b7fb5ba8bec65cb59b all runs: crashed: divide error in choke_change testing release v4.9 testing commit 69973b830859bc6529a7a0468ba0d80ee5117826 with gcc (GCC) 5.5.0 kernel signature: ff6a86a8c7a3ae54dfe501fb46b43c9b53fff3404fbeb8369abcca2b15605cff run #0: crashed: divide error in choke_change run #1: crashed: divide error in choke_change run #2: crashed: divide error in choke_change run #3: crashed: divide error in choke_change run #4: crashed: divide error in choke_change run #5: crashed: divide error in choke_change run #6: crashed: divide error in choke_change run #7: crashed: divide error in choke_change run #8: crashed: divide error in choke_change run #9: basic kernel testing failed: failed to copy test binary to VM: timedout ["scp" "-P" "22" "-F" "/dev/null" "-o" "UserKnownHostsFile=/dev/null" "-o" "BatchMode=yes" "-o" "IdentitiesOnly=yes" "-o" "StrictHostKeyChecking=no" "-o" "ConnectTimeout=10" "-i" "/syzkaller/jobs/linux/workdir/image/key" "/syzkaller/jobs/linux/gopath/src/github.com/google/syzkaller/bin/linux_amd64/syz-execprog" "root@10.128.10.47:./syz-execprog"] Warning: Permanently added '10.128.10.47' (ECDSA) to the list of known hosts. testing release v4.8 testing commit c8d2bc9bc39ebea8437fd974fdbc21847bb897a3 with gcc (GCC) 5.5.0 kernel signature: eae43983fea03b6eb955840c5270823d61c0a40f7ba869884c3ba0cd7f89e6e5 all runs: crashed: divide error in choke_change testing release v4.7 testing commit 523d939ef98fd712632d93a5a2b588e477a7565e with gcc (GCC) 5.5.0 kernel signature: 7afa3125443a99a460467bbd9125216915678e4eb813535922fb271dd25e1e6a all runs: crashed: divide error in choke_change testing release v4.6 testing commit 2dcd0af568b0cf583645c8a317dd12e344b1c72a with gcc (GCC) 5.5.0 kernel signature: 098ff5b900e4fa4f8a61d135cb1b872f69d7927a46c0eb0033de1a1e4508edfd all runs: crashed: WARNING in sysfs_warn_dup revisions tested: 27, total time: 3h36m31.005518409s (build: 2h10m54.709861099s, test: 1h21m27.929854171s) the crash already happened on the oldest tested release commit msg: Linux 4.6 crash: WARNING in sysfs_warn_dup device bridge_slave_0 entered promiscuous mode bridge0: port 2(bridge_slave_1) entered blocking state bridge0: port 2(bridge_slave_1) entered disabled state device bridge_slave_1 entered promiscuous mode ------------[ cut here ]------------ WARNING: CPU: 0 PID: 7873 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: 0 PID: 7873 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 ffff8800b43e6fc8 ffffffff82dab352 ffffffff8667aec0 ffff8800b43e70a0 ffffffff8672c8c0 ffffffff818db72b 0000000000000009 ffff8800b43e7090 ffffffff815c7a54 0000000041b58ab3 ffffffff8778e903 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