bisecting cause commit starting from 7ae77150d94d3b535c7b85e6b3647113095e79bf building syzkaller on e6b89e4e5adde15c0dc0a241e03dc215f2e249b3 testing commit 7ae77150d94d3b535c7b85e6b3647113095e79bf with gcc (GCC) 8.1.0 kernel signature: 3757071b39db33e246dfba3db06246b47514f011274aaa02ab39545ab90adc7c run #0: crashed: INFO: task hung in pipe_write run #1: crashed: INFO: task hung in pipe_write run #2: crashed: INFO: task hung in vfs_unlink run #3: crashed: INFO: task hung in pipe_write run #4: crashed: INFO: task hung in pipe_read run #5: crashed: INFO: task hung in corrupted run #6: crashed: INFO: task hung in pipe_read run #7: crashed: INFO: task hung in pipe_write run #8: crashed: INFO: task hung in pipe_write run #9: crashed: INFO: task hung in pipe_write testing release v5.7 testing commit 3d77e6a8804abcc0504c904bd6e5cdf3a5cf8162 with gcc (GCC) 8.1.0 kernel signature: 8ecd9b7b077f505b5c2b711b769621f22256a2ea41a0a49b478af17404ecea7e run #0: crashed: INFO: task hung in pipe_write run #1: crashed: INFO: task hung in pipe_read run #2: crashed: INFO: task hung in pipe_write run #3: crashed: INFO: task hung in vfs_unlink run #4: crashed: INFO: task hung in pipe_write run #5: crashed: INFO: task hung in pipe_write run #6: crashed: INFO: task hung in pipe_write run #7: crashed: INFO: task hung in pipe_write run #8: crashed: INFO: task hung in pipe_write run #9: crashed: INFO: task hung in pipe_write testing release v5.6 testing commit 7111951b8d4973bda27ff663f2cf18b663d15b48 with gcc (GCC) 8.1.0 kernel signature: a82b391a81a88de812b522a44bb2463ecc23ed790744812ab38df6c8ee80ff1c failed: failed to create VM pool: failed to write image file: googleapi: got HTTP response code 503 with body: Service Unavailable testing release v5.5 testing commit d5226fa6dbae0569ee43ecfc08bdcd6770fc4755 with gcc (GCC) 8.1.0 kernel signature: 444e4bcd1679ddee973231223920a33f506477120c196b94edf933bfe97a9a59 run #0: crashed: INFO: task hung in pipe_write run #1: crashed: INFO: task hung in pipe_write run #2: crashed: INFO: task hung in pipe_write run #3: crashed: INFO: task hung in pipe_write run #4: crashed: INFO: task hung in vfs_unlink run #5: crashed: INFO: task hung in pipe_read run #6: crashed: INFO: task hung in pipe_write run #7: crashed: INFO: task hung in pipe_write run #8: crashed: INFO: task hung in pipe_write run #9: OK testing release v5.4 testing commit 219d54332a09e8d8741c1e1982f5eae56099de85 with gcc (GCC) 8.1.0 kernel signature: e601d02121c3c292d97d77540b1e95b0a93ab58319f0b40c56cc4724f8885e25 run #0: crashed: INFO: task hung in pipe_read run #1: crashed: INFO: task hung in pipe_write run #2: crashed: INFO: task hung in pipe_write run #3: crashed: INFO: task hung in pipe_write run #4: crashed: INFO: task hung in pipe_write run #5: crashed: INFO: task hung in pipe_write run #6: crashed: INFO: task hung in pipe_write run #7: crashed: INFO: task hung in pipe_write run #8: crashed: INFO: task hung in pipe_write run #9: crashed: INFO: task hung in pipe_read testing release v5.3 testing commit 4d856f72c10ecb060868ed10ff1b1453943fc6c8 with gcc (GCC) 8.1.0 kernel signature: 537c83fc09f6c20c7f66ab30bf0b678b2cdee9014bc25bb9be23a822c9cbdf4b run #0: crashed: INFO: task hung in pipe_write run #1: crashed: INFO: task hung in pipe_write run #2: crashed: INFO: task hung in vfs_unlink run #3: crashed: INFO: task hung in pipe_write run #4: crashed: INFO: task hung in pipe_write run #5: crashed: INFO: task hung in pipe_write run #6: crashed: INFO: task hung in pipe_write run #7: crashed: INFO: task hung in pipe_write run #8: crashed: INFO: task hung in pipe_write run #9: OK testing release v5.2 testing commit 0ecfebd2b52404ae0c54a878c872bb93363ada36 with gcc (GCC) 8.1.0 kernel signature: feda79e0d16175878365f26559941d6a225c787d7bfaaa1bac0e3ea2144e984a run #0: crashed: INFO: task hung in pipe_write run #1: crashed: INFO: task hung in pipe_write run #2: crashed: INFO: task hung in pipe_write run #3: crashed: INFO: task hung in pipe_write run #4: crashed: INFO: task hung in vfs_unlink run #5: crashed: INFO: task hung in pipe_read run #6: crashed: INFO: task hung in pipe_write run #7: crashed: INFO: task hung in pipe_write run #8: crashed: INFO: task hung in pipe_write run #9: crashed: INFO: task hung in pipe_read testing release v5.1 testing commit e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd with gcc (GCC) 8.1.0 kernel signature: 1172935892f4230f20d0c332d86e7e758e74017a8cad9b508c5ea16d54e66e55 run #0: crashed: INFO: task hung in vfs_unlink run #1: crashed: INFO: task hung in vfs_unlink run #2: crashed: INFO: task hung in pipe_write run #3: crashed: INFO: task hung in pipe_write run #4: crashed: INFO: task hung in pipe_write run #5: crashed: INFO: task hung in pipe_write run #6: crashed: INFO: task hung in pipe_write run #7: crashed: INFO: task hung in pipe_write run #8: crashed: INFO: task hung in vfs_unlink run #9: crashed: INFO: task hung in pipe_read testing release v5.0 testing commit 1c163f4c7b3f621efff9b28a47abb36f7378d783 with gcc (GCC) 8.1.0 kernel signature: a993d61594cbb5d464b331c344365bafa5a211b84921f1325a9f4f4ede1d570f run #0: crashed: INFO: task hung in pipe_read run #1: crashed: INFO: task hung in pipe_write run #2: crashed: INFO: task hung in pipe_write run #3: crashed: INFO: task hung in pipe_write run #4: crashed: INFO: task hung in pipe_write run #5: crashed: INFO: task hung in pipe_write run #6: crashed: INFO: task hung in pipe_write run #7: crashed: INFO: task hung in pipe_write run #8: crashed: INFO: task hung in pipe_write run #9: crashed: INFO: task hung in pipe_write testing release v4.20 testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.1.0 kernel signature: 56bc4051cbc88519914e474e439300f3ecc5527c76652e60414a5b5257d51c39 all runs: crashed: INFO: task hung in pipe_write testing release v4.19 testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.1.0 kernel signature: 0491e77c6ae4a6b0a60e3bed5d370ac2ef234c7b73c300e3355d3a8a5440387b run #0: crashed: INFO: task hung in pipe_write run #1: crashed: INFO: task hung in pipe_write run #2: crashed: INFO: task hung in pipe_write run #3: crashed: INFO: task hung in vfs_unlink run #4: crashed: INFO: task hung in pipe_write run #5: crashed: INFO: task hung in pipe_read run #6: crashed: INFO: task hung in pipe_read run #7: crashed: INFO: task hung in pipe_write run #8: crashed: INFO: task hung in pipe_write run #9: crashed: INFO: task hung in pipe_write testing release v4.18 testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.1.0 kernel signature: e150292e6733444464646d4c05b440fafc91daf65af66ab032f2704fb730b5d8 run #0: crashed: INFO: task hung in pipe_read run #1: crashed: INFO: task hung in pipe_write run #2: crashed: INFO: task hung in pipe_write run #3: crashed: INFO: task hung in pipe_write run #4: crashed: INFO: task hung in pipe_write run #5: crashed: INFO: task hung in pipe_write run #6: crashed: INFO: task hung in pipe_write run #7: crashed: INFO: task hung in pipe_write run #8: crashed: INFO: task hung in pipe_write run #9: crashed: INFO: task hung in pipe_read testing release v4.17 testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.1.0 kernel signature: 5d212e5c4a59839040487917872e9e41d52ec841d504562feb9a24d4bdb6b922 run #0: crashed: INFO: task hung in vfs_unlink run #1: crashed: INFO: task hung in pipe_write run #2: crashed: INFO: task hung in pipe_read run #3: crashed: INFO: task hung in vfs_unlink run #4: crashed: INFO: task hung in vfs_unlink run #5: crashed: INFO: task hung in pipe_read run #6: crashed: INFO: task hung in pipe_read run #7: crashed: INFO: task hung in pipe_read run #8: crashed: INFO: task hung in pipe_read run #9: crashed: INFO: task hung in pipe_read testing release v4.16 testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.1.0 kernel signature: 6075bda55dad1294fc262a892e4446667cc2ca2ac0e5b63a83141e980600ab26 run #0: crashed: INFO: task hung in pipe_read run #1: crashed: INFO: task hung in pipe_write run #2: crashed: INFO: task hung in pipe_write run #3: crashed: INFO: task hung in vfs_unlink run #4: crashed: INFO: task hung in vfs_unlink run #5: crashed: INFO: task hung in pipe_write run #6: crashed: INFO: task hung in pipe_write run #7: crashed: INFO: task hung in pipe_read run #8: crashed: INFO: task hung in pipe_write run #9: crashed: INFO: task hung in pipe_write testing release v4.15 testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.1.0 kernel signature: 42c77dc2bc71a8285b93a72284a8ea3fc68a15ab9e8184c804dc1d3e90d15781 run #0: crashed: INFO: task hung in pipe_write run #1: crashed: INFO: task hung in pipe_write run #2: crashed: INFO: task hung in pipe_write run #3: crashed: INFO: task hung in pipe_write run #4: crashed: INFO: task hung in pipe_read run #5: crashed: INFO: task hung in vfs_unlink run #6: crashed: INFO: task hung in pipe_read run #7: crashed: INFO: task hung in pipe_read run #8: crashed: INFO: task hung in vfs_unlink run #9: crashed: INFO: task hung in pipe_write testing release v4.14 testing commit bebc6082da0a9f5d47a1ea2edc099bf671058bd4 with gcc (GCC) 8.1.0 kernel signature: 28c8d16a23b36b7080e9bbda64d2c33de308439dbab8303735cf1e354246ba13 run #0: crashed: INFO: task hung in pipe_write run #1: crashed: INFO: task hung in pipe_write run #2: crashed: INFO: task hung in pipe_read run #3: crashed: INFO: task hung in pipe_write run #4: crashed: INFO: task hung in pipe_write run #5: crashed: INFO: task hung in pipe_write run #6: crashed: INFO: task hung in pipe_write run #7: crashed: INFO: task hung in pipe_write run #8: crashed: INFO: task hung in pipe_write run #9: crashed: INFO: task hung in pipe_read testing release v4.13 testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.1.0 kernel signature: 091c3d33e4a91818e13b55d16d1fc3535510d622391e6161265212cd6c781d81 run #0: crashed: INFO: task hung in pipe_read run #1: crashed: INFO: task hung in pipe_write run #2: crashed: INFO: task hung in pipe_read run #3: crashed: INFO: task hung in pipe_write run #4: crashed: INFO: task hung in vfs_unlink run #5: crashed: INFO: task hung in pipe_write run #6: crashed: INFO: task hung in pipe_read run #7: crashed: INFO: task hung in pipe_read run #8: OK run #9: OK testing release v4.12 testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.1.0 kernel signature: 1f3a815024c5a03293dea7883f1bc00edfec6e8602c03c23035cbfc99c7208fd 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: aa605d7dd6a93f6d642f14d7bef54dab325cb3721ee7d02ae757baac8ea14c4f 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: e2d9d0d91550cf4a527eb8d7f1e5c81fdb3c2e1557cbcb8bfb782b391029ac15 run #0: crashed: WARNING in nf_unregister_net_hook run #1: crashed: INFO: suspicious RCU usage in pids_can_fork run #2: crashed: INFO: suspicious RCU usage in pids_can_fork run #3: crashed: INFO: suspicious RCU usage in pids_can_fork run #4: crashed: INFO: suspicious RCU usage in pids_can_fork run #5: crashed: INFO: task hung in vfs_unlink run #6: crashed: INFO: task hung in pipe_read run #7: crashed: INFO: task hung in pipe_read run #8: crashed: INFO: suspicious RCU usage in pids_can_fork run #9: crashed: INFO: task hung in pipe_write testing release v4.9 testing commit 69973b830859bc6529a7a0468ba0d80ee5117826 with gcc (GCC) 5.5.0 kernel signature: 469be44d808332e82288a241220d52375eb60240f72a18fbea976a868af0e3f2 run #0: crashed: WARNING in nf_unregister_net_hook run #1: crashed: INFO: suspicious RCU usage in pids_can_fork run #2: crashed: INFO: suspicious RCU usage in pids_can_fork run #3: crashed: INFO: suspicious RCU usage in pids_can_fork run #4: crashed: INFO: suspicious RCU usage in pids_can_fork run #5: crashed: INFO: suspicious RCU usage in pids_can_fork run #6: crashed: WARNING in nf_unregister_net_hook run #7: crashed: INFO: task hung in vfs_unlink run #8: crashed: INFO: task hung in pipe_write run #9: crashed: INFO: suspicious RCU usage in pids_can_fork testing release v4.8 testing commit c8d2bc9bc39ebea8437fd974fdbc21847bb897a3 with gcc (GCC) 5.5.0 kernel signature: b51615d88f834c87acd49389eab1499b384a0d77b347df9e62ce29c0c6534ac3 run #0: crashed: INFO: suspicious RCU usage in pids_can_fork run #1: crashed: INFO: suspicious RCU usage in pids_can_fork run #2: crashed: INFO: task hung in pipe_write run #3: crashed: INFO: task hung in pipe_write run #4: crashed: INFO: task hung in pipe_write run #5: crashed: INFO: task hung in pipe_write run #6: crashed: INFO: task hung in pipe_write run #7: crashed: INFO: task hung in pipe_write run #8: crashed: INFO: task hung in pipe_read run #9: crashed: INFO: task hung in pipe_write testing release v4.7 testing commit 523d939ef98fd712632d93a5a2b588e477a7565e with gcc (GCC) 5.5.0 kernel signature: e9d3c5a66042eb92a85f508c604e6177ad624c39441ce323d1f70a859e373cd2 run #0: crashed: INFO: task hung in pipe_read run #1: crashed: INFO: task hung in pipe_read run #2: crashed: INFO: task hung in pipe_write run #3: crashed: INFO: task hung in pipe_write run #4: crashed: INFO: task hung in vfs_unlink run #5: crashed: INFO: task hung in pipe_write run #6: crashed: INFO: task hung in pipe_write run #7: crashed: INFO: task hung in pipe_write run #8: crashed: INFO: task hung in pipe_write run #9: crashed: INFO: task hung in pipe_write testing release v4.6 testing commit 2dcd0af568b0cf583645c8a317dd12e344b1c72a with gcc (GCC) 5.5.0 kernel signature: fe6fad006fbf2d2bd8a5de6a2ee487d355264fe66f67d81b92cbed0d67b75a99 all runs: crashed: WARNING in sysfs_warn_dup revisions tested: 24, total time: 5h18m2.202367652s (build: 2h10m40.596842903s, test: 3h4m54.601241661s) 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_1: link is not ready IPv6: ADDRCONF(NETDEV_UP): bridge0: link is not ready 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 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 5869 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: 5869 Comm: syz-executor.1 Not tainted 4.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 0000000000000000 ffff8800b1cf6fc8 ffffffff82c65e52 ffffffff85c81040 ffff8800b1cf70a0 ffffffff85d2bb80 ffffffff8191bd7b 0000000000000009 ffff8800b1cf7090 ffffffff8160d884 0000000041b58ab3 ffffffff868f05e2 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