bisecting cause commit starting from 34d4ddd359dbcdf6c5fb3f85a179243d7a1cb7f8 building syzkaller on 409809d8a7c9c775eaea317add40e7a86a1e836c testing commit 34d4ddd359dbcdf6c5fb3f85a179243d7a1cb7f8 with gcc (GCC) 8.1.0 kernel signature: d26e98017bc3c9be21591fb1fe6f6dfd01de08d7c18d1681c6d153edfde48a19 run #0: crashed: WARNING: bad unlock balance in ucma_destroy_id run #1: crashed: WARNING: bad unlock balance in ucma_destroy_id run #2: crashed: WARNING: bad unlock balance in ucma_destroy_id run #3: crashed: WARNING: bad unlock balance in ucma_destroy_id run #4: crashed: WARNING: refcount bug in ucma_close run #5: crashed: WARNING: bad unlock balance detected! run #6: crashed: WARNING: bad unlock balance in ucma_destroy_id run #7: crashed: WARNING: bad unlock balance in ucma_destroy_id run #8: crashed: WARNING: bad unlock balance in ucma_destroy_id run #9: crashed: WARNING: bad unlock balance in ucma_destroy_id testing release v5.8 testing commit bcf876870b95592b52519ed4aafcf9d95999bc9c with gcc (GCC) 8.1.0 kernel signature: 1c56b449d687ebda20b5d613ed6cb03bc2f965606909cfcd97d49052aadacff0 run #0: crashed: WARNING: bad unlock balance detected! run #1: crashed: WARNING: bad unlock balance in ucma_destroy_id run #2: crashed: WARNING: bad unlock balance in ucma_destroy_id run #3: crashed: WARNING: bad unlock balance in ucma_destroy_id run #4: crashed: WARNING: bad unlock balance in ucma_destroy_id run #5: crashed: WARNING: bad unlock balance in ucma_destroy_id run #6: crashed: WARNING: bad unlock balance in ucma_destroy_id run #7: crashed: WARNING: bad unlock balance in ucma_destroy_id run #8: crashed: WARNING: refcount bug in ucma_close run #9: crashed: WARNING: bad unlock balance in ucma_destroy_id testing release v5.7 testing commit 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162 with gcc (GCC) 8.1.0 kernel signature: eefd575b221aa8cef449741819e575f35a176031b75c33637247d61f336813e6 run #0: crashed: WARNING: bad unlock balance in ucma_destroy_id run #1: crashed: WARNING: bad unlock balance detected! run #2: crashed: WARNING: bad unlock balance detected! run #3: crashed: WARNING: bad unlock balance in ucma_destroy_id run #4: crashed: WARNING: bad unlock balance detected! run #5: crashed: WARNING: bad unlock balance detected! run #6: crashed: WARNING: bad unlock balance detected! run #7: crashed: WARNING: bad unlock balance detected! run #8: crashed: WARNING: bad unlock balance in ucma_destroy_id run #9: crashed: WARNING: bad unlock balance detected! testing release v5.6 testing commit 7111951b8d4973bda27ff663f2cf18b663d15b48 with gcc (GCC) 8.1.0 kernel signature: b6911fccf947c1fd3155e2bc61b33ecd05c7d149d9f1a8238f7cf8552f28d08f run #0: crashed: WARNING: bad unlock balance detected! run #1: crashed: WARNING: bad unlock balance in ucma_destroy_id run #2: crashed: WARNING: bad unlock balance in ucma_destroy_id run #3: crashed: WARNING: bad unlock balance detected! run #4: crashed: WARNING: bad unlock balance detected! run #5: crashed: WARNING: bad unlock balance detected! run #6: crashed: WARNING: bad unlock balance detected! run #7: crashed: WARNING: bad unlock balance in ucma_destroy_id run #8: crashed: WARNING: bad unlock balance detected! run #9: crashed: WARNING: bad unlock balance detected! testing release v5.5 testing commit d5226fa6dbae0569ee43ecfc08bdcd6770fc4755 with gcc (GCC) 8.1.0 kernel signature: 94e4a8ad8df8bac1e95a039ad22cedb980869ff3587dbf6d892d910351b8a1a9 run #0: crashed: WARNING: bad unlock balance detected! run #1: crashed: WARNING: bad unlock balance in ucma_destroy_id run #2: crashed: WARNING: bad unlock balance in ucma_destroy_id run #3: crashed: WARNING: bad unlock balance detected! run #4: crashed: WARNING: bad unlock balance detected! run #5: crashed: WARNING: bad unlock balance in ucma_destroy_id run #6: crashed: WARNING: bad unlock balance detected! run #7: crashed: WARNING: bad unlock balance detected! run #8: crashed: WARNING: bad unlock balance detected! run #9: crashed: WARNING: bad unlock balance in ucma_destroy_id testing release v5.4 testing commit 219d54332a09e8d8741c1e1982f5eae56099de85 with gcc (GCC) 8.1.0 kernel signature: 5a01ded45fdcdc51d2276d7fb9dbe20852f89301a267705394e4ab27ac21c806 run #0: crashed: WARNING: bad unlock balance detected! run #1: crashed: WARNING: bad unlock balance detected! run #2: crashed: WARNING: bad unlock balance in ucma_destroy_id run #3: crashed: WARNING: bad unlock balance in ucma_destroy_id run #4: crashed: WARNING: bad unlock balance in ucma_destroy_id run #5: crashed: WARNING: bad unlock balance in ucma_destroy_id run #6: crashed: WARNING: bad unlock balance in ucma_destroy_id run #7: crashed: WARNING: bad unlock balance in ucma_destroy_id run #8: crashed: WARNING: bad unlock balance detected! run #9: crashed: WARNING: bad unlock balance detected! testing release v5.3 testing commit 4d856f72c10ecb060868ed10ff1b1453943fc6c8 with gcc (GCC) 8.1.0 kernel signature: c85fe86cc32c176fb7dbbf398771a1f5c9729d1f0e36c7ccee663416517f40eb all runs: crashed: INFO: task hung in ucma_close testing release v5.2 testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.1.0 kernel signature: b6ec6a9e88c34bdf1668d7456cbdf199185b45a4c993d764f7a7c5ed1d8a9f77 run #0: crashed: WARNING: bad unlock balance detected! run #1: crashed: KASAN: use-after-free Read in wait_for_common run #2: crashed: WARNING: bad unlock balance detected! run #3: crashed: WARNING: bad unlock balance in ucma_destroy_id run #4: crashed: WARNING: bad unlock balance detected! run #5: crashed: WARNING: bad unlock balance detected! run #6: crashed: WARNING: bad unlock balance detected! run #7: crashed: WARNING: bad unlock balance in ucma_destroy_id run #8: crashed: BUG: MAX_STACK_TRACE_ENTRIES too low! run #9: crashed: BUG: MAX_STACK_TRACE_ENTRIES too low! testing release v5.1 testing commit e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd with gcc (GCC) 8.1.0 kernel signature: 8efa02d70bbfbbef7224e6602061965a88c0b2b92d9a5847aff6776858f3514c run #0: crashed: WARNING: bad unlock balance in ucma_destroy_id run #1: crashed: WARNING: bad unlock balance detected! run #2: crashed: WARNING: bad unlock balance in ucma_destroy_id run #3: crashed: WARNING: bad unlock balance in ucma_destroy_id run #4: crashed: WARNING: bad unlock balance in ucma_destroy_id run #5: crashed: WARNING: bad unlock balance detected! run #6: crashed: WARNING: bad unlock balance detected! run #7: crashed: WARNING: bad unlock balance in ucma_destroy_id run #8: crashed: WARNING: bad unlock balance detected! run #9: crashed: WARNING: bad unlock balance in ucma_destroy_id testing release v5.0 testing commit 1c163f4c7b3f621efff9b28a47abb36f7378d783 with gcc (GCC) 8.1.0 kernel signature: 3a85d9cfe466d0815f322040ab603c9bd11c026e20e80a5aa5161825c5c94a44 run #0: crashed: WARNING: bad unlock balance in ucma_destroy_id run #1: crashed: WARNING: bad unlock balance detected! run #2: crashed: WARNING: bad unlock balance detected! run #3: crashed: WARNING: bad unlock balance detected! run #4: crashed: WARNING: bad unlock balance in ucma_destroy_id run #5: crashed: WARNING: bad unlock balance in ucma_destroy_id run #6: crashed: WARNING: bad unlock balance in ucma_destroy_id run #7: crashed: WARNING: bad unlock balance detected! run #8: crashed: WARNING: bad unlock balance in ucma_destroy_id run #9: crashed: WARNING: bad unlock balance detected! testing release v4.20 testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.1.0 kernel signature: 9a9396799c786b1647b1f1825ee14966d5903e3d84a46292735e3ff462b09c90 all runs: crashed: WARNING: bad unlock balance detected! testing release v4.19 testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.1.0 kernel signature: 5e7fd48f650e85592a94ddecbc90c1b693a80c5b1780bc5f5aa37a5089f8ab8e run #0: crashed: WARNING: bad unlock balance detected! run #1: crashed: WARNING: bad unlock balance in ucma_destroy_id run #2: crashed: WARNING: bad unlock balance detected! run #3: crashed: KASAN: use-after-free Read in wait_for_common run #4: crashed: WARNING: bad unlock balance detected! run #5: crashed: WARNING: bad unlock balance in ucma_destroy_id run #6: crashed: WARNING: bad unlock balance detected! run #7: crashed: WARNING: bad unlock balance detected! run #8: crashed: WARNING: bad unlock balance in ucma_destroy_id run #9: crashed: WARNING: bad unlock balance detected! testing release v4.18 testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.1.0 kernel signature: 79759281c83baa5e55b3a33081b954309a1afca47e3c8d8627139e0e1ea52eb1 run #0: crashed: WARNING: bad unlock balance detected! run #1: crashed: KASAN: use-after-free Read in ucma_close run #2: crashed: KASAN: use-after-free Read in wait_for_common run #3: crashed: WARNING: bad unlock balance detected! run #4: crashed: WARNING: bad unlock balance detected! run #5: crashed: KASAN: use-after-free Read in wait_for_common run #6: crashed: WARNING: bad unlock balance detected! run #7: crashed: WARNING: bad unlock balance detected! run #8: crashed: WARNING: bad unlock balance detected! run #9: crashed: WARNING: bad unlock balance detected! testing release v4.17 testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.1.0 kernel signature: 6e938c4748911cd85bd6fef493e8cf6e0024a967420d5aa64ec447a2d3abc69f run #0: crashed: WARNING: bad unlock balance in ucma_destroy_id run #1: crashed: WARNING: bad unlock balance in ucma_destroy_id run #2: crashed: WARNING: bad unlock balance detected! run #3: crashed: WARNING: bad unlock balance in ucma_destroy_id run #4: crashed: WARNING: bad unlock balance in ucma_destroy_id run #5: crashed: WARNING: bad unlock balance detected! run #6: crashed: WARNING: bad unlock balance detected! run #7: crashed: WARNING: bad unlock balance detected! run #8: crashed: WARNING: bad unlock balance detected! run #9: crashed: WARNING: bad unlock balance in ucma_destroy_id testing release v4.16 testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.1.0 kernel signature: 6da47662f02fad6ad2a5aae51e3a5abcede572ee5b0d0eab4b8963d0b8ccb35c run #0: crashed: WARNING: bad unlock balance in ucma_destroy_id run #1: crashed: WARNING: bad unlock balance in ucma_destroy_id run #2: crashed: WARNING: bad unlock balance in ucma_destroy_id run #3: crashed: WARNING: bad unlock balance detected! run #4: crashed: WARNING: bad unlock balance detected! run #5: crashed: WARNING: bad unlock balance detected! run #6: crashed: WARNING: bad unlock balance detected! run #7: crashed: KASAN: use-after-free Read in rdma_destroy_id run #8: crashed: WARNING: bad unlock balance detected! run #9: crashed: INFO: task hung in rdma_destroy_id testing release v4.15 testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.1.0 kernel signature: 1c5b778616ff38683f8311b69ddef073d07ceec921693f23859b05f6744eabb3 run #0: crashed: WARNING: bad unlock balance detected! run #1: crashed: WARNING: bad unlock balance in ucma_destroy_id run #2: crashed: WARNING: bad unlock balance detected! run #3: crashed: WARNING: bad unlock balance detected! run #4: crashed: WARNING: bad unlock balance detected! run #5: crashed: WARNING: bad unlock balance detected! run #6: crashed: general protection fault in rdma_destroy_id run #7: crashed: WARNING: bad unlock balance detected! run #8: crashed: general protection fault in rdma_destroy_id run #9: crashed: general protection fault in rdma_destroy_id testing release v4.14 testing commit bebc6082da0a9f5d47a1ea2edc099bf671058bd4 with gcc (GCC) 8.1.0 kernel signature: e40df55e3254e68615b1280b8623bb8ac6c512340a619df49a48dd7ce5fe4a7a run #0: crashed: WARNING: bad unlock balance in ucma_destroy_id run #1: crashed: WARNING: bad unlock balance in ucma_destroy_id run #2: crashed: WARNING: bad unlock balance detected! run #3: crashed: KASAN: use-after-free Read in wait_for_common run #4: crashed: WARNING: bad unlock balance detected! run #5: crashed: WARNING: bad unlock balance in ucma_destroy_id run #6: crashed: general protection fault in rdma_destroy_id run #7: crashed: WARNING: bad unlock balance detected! run #8: crashed: WARNING: bad unlock balance detected! run #9: crashed: WARNING: bad unlock balance detected! testing release v4.13 testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.1.0 kernel signature: 39842781c24afd4c775e41cc5de0f98206e938c7985a1ce85ad13c65ce0532f6 run #0: crashed: KASAN: use-after-free Read in rdma_destroy_id run #1: crashed: WARNING: bad unlock balance detected! run #2: crashed: KASAN: use-after-free Read in wait_for_common run #3: crashed: WARNING: bad unlock balance detected! run #4: crashed: WARNING: bad unlock balance detected! run #5: crashed: WARNING: bad unlock balance detected! run #6: crashed: WARNING: bad unlock balance detected! run #7: crashed: WARNING: bad unlock balance detected! run #8: crashed: WARNING: bad unlock balance detected! run #9: crashed: INFO: task hung in rdma_destroy_id testing release v4.12 testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.1.0 kernel signature: 6c7a3dabe9ca0a2a76b8dc87e2337a072179472005b83eb484e1aeaaaf85038c 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: 7b48efc1e615e195e3cbb85b8252fc881aba6d23237c5fe033577473c82a8c0b 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: 1b4d11da9e50a800240bcfdfe87850875677fe07c5ab5965318929f08dd845d8 run #0: crashed: WARNING in idr_remove run #1: crashed: WARNING in idr_remove run #2: crashed: WARNING in idr_remove run #3: crashed: WARNING in idr_remove run #4: crashed: WARNING in idr_remove run #5: crashed: BUG: bad unlock balance detected! ] run #6: crashed: WARNING in idr_remove run #7: crashed: WARNING in idr_remove run #8: crashed: WARNING in idr_remove run #9: crashed: KASAN: use-after-free Read in ucma_close testing release v4.9 testing commit 69973b830859bc6529a7a0468ba0d80ee5117826 with gcc (GCC) 5.5.0 kernel signature: f6ae2b7c5f1efa2356dbdbf612519a2bf762df131f4b9e42f1bab6e5443815ad run #0: crashed: BUG: bad unlock balance in mutex_unlock run #1: crashed: general protection fault in rdma_destroy_id run #2: crashed: general protection fault in rdma_destroy_id run #3: crashed: BUG: bad unlock balance in mutex_unlock run #4: crashed: BUG: bad unlock balance in mutex_unlock run #5: crashed: WARNING in corrupted run #6: crashed: BUG: bad unlock balance in mutex_unlock run #7: crashed: BUG: bad unlock balance in mutex_unlock run #8: crashed: BUG: bad unlock balance in mutex_unlock run #9: crashed: KASAN: use-after-free Write in ucma_destroy_id testing release v4.8 testing commit c8d2bc9bc39ebea8437fd974fdbc21847bb897a3 with gcc (GCC) 5.5.0 kernel signature: f9363a9e8465bb13b62237d6bc46cec785a172b9b5fea1fe4526514c95cd50c7 run #0: crashed: BUG: bad unlock balance in mutex_unlock run #1: crashed: general protection fault in rdma_destroy_id run #2: crashed: general protection fault in rdma_destroy_id run #3: crashed: general protection fault in rdma_destroy_id run #4: crashed: general protection fault in rdma_destroy_id run #5: crashed: general protection fault in rdma_destroy_id run #6: crashed: general protection fault in rdma_destroy_id run #7: crashed: BUG: bad unlock balance in mutex_unlock run #8: crashed: general protection fault in rdma_destroy_id run #9: crashed: BUG: bad unlock balance in mutex_unlock testing release v4.7 testing commit 523d939ef98fd712632d93a5a2b588e477a7565e with gcc (GCC) 5.5.0 kernel signature: 37b0ae61359aaac9d7fe2a470d75bcb4f6915b1f496264f6d5fa588592b7a5d2 run #0: crashed: BUG: bad unlock balance in mutex_unlock run #1: crashed: general protection fault in rdma_destroy_id run #2: crashed: BUG: bad unlock balance in mutex_unlock run #3: crashed: general protection fault in rdma_destroy_id run #4: crashed: general protection fault in rdma_destroy_id run #5: crashed: general protection fault in rdma_destroy_id run #6: crashed: general protection fault in rdma_destroy_id run #7: crashed: general protection fault in rdma_destroy_id run #8: crashed: BUG: bad unlock balance in mutex_unlock run #9: crashed: general protection fault in rdma_destroy_id testing release v4.6 testing commit 2dcd0af568b0cf583645c8a317dd12e344b1c72a with gcc (GCC) 5.5.0 kernel signature: cf653ebd8b84f7dfb730c3f69670b6d5643edded757bb54b6b29403bfd7ced95 all runs: crashed: WARNING in sysfs_warn_dup revisions tested: 25, total time: 3h56m54.439460843s (build: 2h13m45.723316525s, test: 1h39m23.644349922s) 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 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 5901 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: 5901 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 ffff880129a46fc8 ffffffff82c65e52 ffffffff85c81040 ffff880129a470a0 ffffffff85d2bb80 ffffffff8191bd7b 0000000000000009 ffff880129a47090 ffffffff8160d884 0000000041b58ab3 ffffffff868f8c5a 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