====================================================== WARNING: possible circular locking dependency detected 4.14.232-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/15788 is trying to acquire lock: (&event->child_mutex){+.+.}, at: [] perf_event_read_value+0x78/0x410 kernel/events/core.c:4453 but task is already holding lock: (&cpuctx_mutex){+.+.}, at: [] perf_event_ctx_lock_nested+0x14d/0x2c0 kernel/events/core.c:1241 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:11250 perf_event_init+0x2cc/0x308 kernel/events/core.c:11297 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:11244 cpuhp_invoke_callback+0x1e6/0x1a80 kernel/cpu.c:184 cpuhp_up_callbacks kernel/cpu.c:572 [inline] _cpu_up+0x219/0x500 kernel/cpu.c:1144 netlink: 12 bytes leftover after parsing attributes in process `syz-executor.3'. do_cpu_up+0x9a/0x160 kernel/cpu.c:1179 smp_init+0x197/0x1ac kernel/smp.c:578 kernel_init_freeable+0x3f4/0x614 init/main.c:1068 kernel_init+0xd/0x165 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+0x747/0xa40 kernel/tracepoint.c:269 tracepoint_probe_register_prio kernel/tracepoint.c:331 [inline] tracepoint_probe_register+0x8c/0xc0 kernel/tracepoint.c:352 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:8138 perf_try_init_event+0x15b/0x1f0 kernel/events/core.c:9369 perf_init_event kernel/events/core.c:9407 [inline] perf_event_alloc.part.0+0xe2d/0x2640 kernel/events/core.c:9667 perf_event_alloc kernel/events/core.c:10020 [inline] SYSC_perf_event_open kernel/events/core.c:10124 [inline] SyS_perf_event_open+0x67f/0x24b0 kernel/events/core.c:10010 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:327 [inline] tracepoint_probe_register+0x68/0xc0 kernel/tracepoint.c:352 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:8138 perf_try_init_event+0x15b/0x1f0 kernel/events/core.c:9369 perf_init_event kernel/events/core.c:9407 [inline] perf_event_alloc.part.0+0xe2d/0x2640 kernel/events/core.c:9667 perf_event_alloc kernel/events/core.c:10020 [inline] SYSC_perf_event_open kernel/events/core.c:10124 [inline] SyS_perf_event_open+0x67f/0x24b0 kernel/events/core.c:10010 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:4244 free_event+0x32/0x40 kernel/events/core.c:4271 perf_event_release_kernel+0x368/0x8a0 kernel/events/core.c:4415 perf_release+0x33/0x40 kernel/events/core.c:4441 __fput+0x25f/0x7a0 fs/file_table.c:210 task_work_run+0x11f/0x190 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xa44/0x2850 kernel/exit.c:868 do_group_exit+0x100/0x2e0 kernel/exit.c:965 get_signal+0x38d/0x1ca0 kernel/signal.c:2423 do_signal+0x7c/0x1550 arch/x86/kernel/signal.c:792 exit_to_usermode_loop+0x160/0x200 arch/x86/entry/common.c:160 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_event_read_value+0x78/0x410 kernel/events/core.c:4453 perf_read_one kernel/events/core.c:4575 [inline] __perf_read kernel/events/core.c:4626 [inline] perf_read+0x3e2/0x7c0 kernel/events/core.c:4639 __vfs_read+0xe4/0x620 fs/read_write.c:411 vfs_read+0x139/0x340 fs/read_write.c:447 SYSC_read fs/read_write.c:574 [inline] SyS_read+0xf2/0x210 fs/read_write.c:567 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.0/15788: #0: (&cpuctx_mutex){+.+.}, at: [] perf_event_ctx_lock_nested+0x14d/0x2c0 kernel/events/core.c:1241 stack backtrace: CPU: 0 PID: 15788 Comm: syz-executor.0 Not tainted 4.14.232-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+0x1b2/0x281 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_event_read_value+0x78/0x410 kernel/events/core.c:4453 perf_read_one kernel/events/core.c:4575 [inline] __perf_read kernel/events/core.c:4626 [inline] perf_read+0x3e2/0x7c0 kernel/events/core.c:4639 __vfs_read+0xe4/0x620 fs/read_write.c:411 vfs_read+0x139/0x340 fs/read_write.c:447 SYSC_read fs/read_write.c:574 [inline] SyS_read+0xf2/0x210 fs/read_write.c:567 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x4665d9 RSP: 002b:00007ff0a1154188 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 00000000004665d9 RDX: 0000000000002020 RSI: 00000000200021c0 RDI: 0000000000000003 RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60 R13: 00007fff54b5557f R14: 00007ff0a1154300 R15: 0000000000022000 tmpfs: Bad value '0xffffffffffffffff' for mount option 'uid' tmpfs: Bad value '0xffffffffffffffff' for mount option 'uid' 9pnet: p9_fd_create_tcp (16086): problem connecting socket to 127.0.0.1 9pnet: p9_fd_create_tcp (16091): problem connecting socket to 127.0.0.1 audit: type=1326 audit(1621109312.863:13776): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=16132 comm="syz-executor.5" exe="/root/syz-executor.5" sig=31 arch=c000003e syscall=202 compat=0 ip=0x4665d9 code=0x0 nla_parse: 3 callbacks suppressed netlink: 56 bytes leftover after parsing attributes in process `syz-executor.5'. 9pnet: Could not find request transport: tcpE 9pnet: Could not find request transport: tcpE tmpfs: Bad value 'prefer=static::' for mount option 'mpol' tmpfs: Bad value 'prefer=static::' for mount option 'mpol' audit: type=1326 audit(1621109314.954:13777): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=16290 comm="syz-executor.5" exe="/root/syz-executor.5" sig=31 arch=c000003e syscall=202 compat=0 ip=0x4665d9 code=0x0 netlink: 4 bytes leftover after parsing attributes in process `syz-executor.3'. base_sock_release(ffff888043354900) sk=ffff8880a7b9d200 base_sock_release(ffff88804b618540) sk=ffff8880a8845300 netlink: 4 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 4 bytes leftover after parsing attributes in process `syz-executor.5'. ODEBUG: free active (active state 1) object type: rcu_head hint: (null) ------------[ cut here ]------------ WARNING: CPU: 0 PID: 16884 at lib/debugobjects.c:287 debug_print_object.cold+0xa7/0xdb lib/debugobjects.c:287