====================================================== WARNING: possible circular locking dependency detected 4.14.196-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.1/13587 is trying to acquire lock: (&event->child_mutex){+.+.}, at: [] perf_read_group kernel/events/core.c:4541 [inline] (&event->child_mutex){+.+.}, at: [] __perf_read kernel/events/core.c:4623 [inline] (&event->child_mutex){+.+.}, at: [] perf_read+0x2a2/0x7c0 kernel/events/core.c:4638 but task is already holding lock: (&cpuctx_mutex){+.+.}, at: [] perf_event_ctx_lock_nested+0x14d/0x2c0 kernel/events/core.c:1240 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&cpuctx_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 perf_event_init_cpu+0xb7/0x170 kernel/events/core.c:11249 perf_event_init+0x2cc/0x308 kernel/events/core.c:11296 start_kernel+0x46a/0x770 init/main.c:620 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:240 -> #4 (pmus_lock){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 perf_event_init_cpu+0x2c/0x170 kernel/events/core.c:11243 cpuhp_invoke_callback+0x1e6/0x1a80 kernel/cpu.c:184 cpuhp_up_callbacks kernel/cpu.c:572 [inline] _cpu_up+0x219/0x500 kernel/cpu.c:1140 do_cpu_up+0x9a/0x160 kernel/cpu.c:1175 smp_init+0x197/0x1ac kernel/smp.c:578 kernel_init_freeable+0x3f4/0x619 init/main.c:1068 kernel_init+0xd/0x15b init/main.c:1000 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 -> #3 (cpu_hotplug_lock.rw_sem){++++}: percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline] percpu_down_read include/linux/percpu-rwsem.h:59 [inline] cpus_read_lock+0x39/0xc0 kernel/cpu.c:295 static_key_slow_inc+0xe/0x20 kernel/jump_label.c:123 tracepoint_add_func+0x517/0x750 kernel/tracepoint.c:223 tracepoint_probe_register_prio kernel/tracepoint.c:283 [inline] tracepoint_probe_register+0x8c/0xc0 kernel/tracepoint.c:304 trace_event_reg+0x272/0x330 kernel/trace/trace_events.c:305 perf_trace_event_reg kernel/trace/trace_event_perf.c:122 [inline] perf_trace_event_init kernel/trace/trace_event_perf.c:197 [inline] perf_trace_init+0x424/0xa30 kernel/trace/trace_event_perf.c:221 perf_tp_event_init+0x79/0xf0 kernel/events/core.c:8132 perf_try_init_event+0x15b/0x1f0 kernel/events/core.c:9368 perf_init_event kernel/events/core.c:9406 [inline] perf_event_alloc.part.0+0xe2d/0x2640 kernel/events/core.c:9666 perf_event_alloc kernel/events/core.c:10019 [inline] SYSC_perf_event_open kernel/events/core.c:10123 [inline] SyS_perf_event_open+0x67f/0x24b0 kernel/events/core.c:10009 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #2 (tracepoints_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 tracepoint_probe_register_prio kernel/tracepoint.c:279 [inline] tracepoint_probe_register+0x68/0xc0 kernel/tracepoint.c:304 trace_event_reg+0x272/0x330 kernel/trace/trace_events.c:305 perf_trace_event_reg kernel/trace/trace_event_perf.c:122 [inline] perf_trace_event_init kernel/trace/trace_event_perf.c:197 [inline] perf_trace_init+0x424/0xa30 kernel/trace/trace_event_perf.c:221 perf_tp_event_init+0x79/0xf0 kernel/events/core.c:8132 perf_try_init_event+0x15b/0x1f0 kernel/events/core.c:9368 perf_init_event kernel/events/core.c:9406 [inline] perf_event_alloc.part.0+0xe2d/0x2640 kernel/events/core.c:9666 perf_event_alloc kernel/events/core.c:10019 [inline] SYSC_perf_event_open kernel/events/core.c:10123 [inline] SyS_perf_event_open+0x67f/0x24b0 kernel/events/core.c:10009 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #1 (event_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 perf_trace_destroy+0x23/0xf0 kernel/trace/trace_event_perf.c:234 _free_event+0x321/0xe20 kernel/events/core.c:4243 free_event+0x32/0x40 kernel/events/core.c:4270 perf_event_release_kernel+0x368/0x8a0 kernel/events/core.c:4414 perf_release+0x33/0x40 kernel/events/core.c:4440 __fput+0x25f/0x7a0 fs/file_table.c:210 task_work_run+0x11f/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #0 (&event->child_mutex){+.+.}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 perf_read_group kernel/events/core.c:4541 [inline] __perf_read kernel/events/core.c:4623 [inline] perf_read+0x2a2/0x7c0 kernel/events/core.c:4638 do_loop_readv_writev fs/read_write.c:695 [inline] do_loop_readv_writev fs/read_write.c:682 [inline] do_iter_read+0x3eb/0x5b0 fs/read_write.c:919 vfs_readv+0xc8/0x120 fs/read_write.c:981 do_readv+0xfc/0x2c0 fs/read_write.c:1014 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb other info that might help us debug this: Chain exists of: &event->child_mutex --> pmus_lock --> &cpuctx_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&cpuctx_mutex); lock(pmus_lock); lock(&cpuctx_mutex); lock(&event->child_mutex); *** DEADLOCK *** 1 lock held by syz-executor.1/13587: #0: (&cpuctx_mutex){+.+.}, at: [] perf_event_ctx_lock_nested+0x14d/0x2c0 kernel/events/core.c:1240 stack backtrace: CPU: 1 PID: 13587 Comm: syz-executor.1 Not tainted 4.14.196-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x283 lib/dump_stack.c:58 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1905 [inline] check_prevs_add kernel/locking/lockdep.c:2022 [inline] validate_chain kernel/locking/lockdep.c:2464 [inline] __lock_acquire+0x2e0e/0x3f20 kernel/locking/lockdep.c:3491 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 perf_read_group kernel/events/core.c:4541 [inline] __perf_read kernel/events/core.c:4623 [inline] perf_read+0x2a2/0x7c0 kernel/events/core.c:4638 do_loop_readv_writev fs/read_write.c:695 [inline] do_loop_readv_writev fs/read_write.c:682 [inline] do_iter_read+0x3eb/0x5b0 fs/read_write.c:919 vfs_readv+0xc8/0x120 fs/read_write.c:981 do_readv+0xfc/0x2c0 fs/read_write.c:1014 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45d5b9 RSP: 002b:00007f67f74d6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000013 RAX: ffffffffffffffda RBX: 00000000000266c0 RCX: 000000000045d5b9 RDX: 0000000000000004 RSI: 000000002058c000 RDI: 0000000000000004 RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007fff625e6f0f R14: 00007f67f74d79c0 R15: 000000000118cf4c 9pnet: p9_fd_create_tcp (13703): problem connecting socket to 127.0.0.1 audit: type=1400 audit(1599608540.373:39): avc: denied { sys_admin } for pid=13722 comm="syz-executor.5" capability=21 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=cap_userns permissive=1 caif:caif_disconnect_client(): nothing to disconnect caif:caif_disconnect_client(): nothing to disconnect print_req_error: 174 callbacks suppressed print_req_error: I/O error, dev loop5, sector 18 print_req_error: I/O error, dev loop5, sector 18 buffer_io_error: 150 callbacks suppressed Buffer I/O error on dev loop5p1, logical block 8, async page read print_req_error: I/O error, dev loop5, sector 19 Buffer I/O error on dev loop5p1, logical block 9, async page read print_req_error: I/O error, dev loop5, sector 8 print_req_error: I/O error, dev loop5, sector 20 Buffer I/O error on dev loop5p1, logical block 10, async page read print_req_error: I/O error, dev loop5, sector 8 Buffer I/O error on dev loop5p4, logical block 8, async page read print_req_error: I/O error, dev loop5, sector 9 Buffer I/O error on dev loop5p4, logical block 9, async page read print_req_error: I/O error, dev loop5, sector 10 Buffer I/O error on dev loop5p4, logical block 10, async page read print_req_error: I/O error, dev loop5, sector 11 print_req_error: I/O error, dev loop5, sector 12 Buffer I/O error on dev loop5p4, logical block 11, async page read Buffer I/O error on dev loop5p4, logical block 12, async page read Buffer I/O error on dev loop5p4, logical block 13, async page read Buffer I/O error on dev loop5p4, logical block 14, async page read sctp: [Deprecated]: syz-executor.4 (pid 13929) Use of int in max_burst socket option. Use struct sctp_assoc_value instead netlink: 4 bytes leftover after parsing attributes in process `syz-executor.4'. ntfs: (device nullb0): read_ntfs_boot_sector(): Primary boot sector is invalid. (unnamed net_device) (uninitialized): HSR: No slave devices specified ntfs: (device nullb0): read_ntfs_boot_sector(): Mount option errors=recover not used. Aborting without trying to recover. ntfs: (device nullb0): ntfs_fill_super(): Not an NTFS volume. ntfs: (device nullb0): read_ntfs_boot_sector(): Primary boot sector is invalid. SELinux: unrecognized netlink message: protocol=0 nlmsg_type=65535 sclass=netlink_route_socket pid=13980 comm=syz-executor.3 ntfs: (device nullb0): read_ntfs_boot_sector(): Mount option errors=recover not used. Aborting without trying to recover. SELinux: unrecognized netlink message: protocol=0 nlmsg_type=65535 sclass=netlink_route_socket pid=13999 comm=syz-executor.3 ntfs: (device nullb0): ntfs_fill_super(): Not an NTFS volume. IPVS: ftp: loaded support on port[0] = 21 audit: type=1800 audit(1599608542.323:40): pid=14037 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.3" name="file0" dev="sda1" ino=16431 res=0 audit: type=1800 audit(1599608542.383:41): pid=14037 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.3" name="file0" dev="sda1" ino=16431 res=0 IPVS: ftp: loaded support on port[0] = 21 usb usb9: usbfs: process 14140 (syz-executor.4) did not claim interface 0 before use IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready caif:caif_disconnect_client(): nothing to disconnect IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready usb usb9: usbfs: process 14140 (syz-executor.4) did not claim interface 0 before use caif:caif_disconnect_client(): nothing to disconnect IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. caif:caif_disconnect_client(): nothing to disconnect caif:caif_disconnect_client(): nothing to disconnect block nbd3: Receive control failed (result -107) block nbd3: Attempted send on invalid socket block nbd3: shutting down sockets ldm_validate_partition_table(): Disk read failed. Dev nbd3: unable to read RDB block 0 nbd3: unable to read partition table block nbd3: Receive control failed (result -107) block nbd3: shutting down sockets