====================================================== WARNING: possible circular locking dependency detected 4.13.0-mm1+ #7 Not tainted ------------------------------------------------------ syz-executor0/3135 is trying to acquire lock: (event_mutex){+.+.}, at: [] perf_trace_destroy+0x28/0x100 kernel/trace/trace_event_perf.c:234 but task is already holding lock: (&mm->mmap_sem){++++}, at: [] vm_mmap_pgoff+0x198/0x280 mm/util.c:331 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&mm->mmap_sem){++++}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 __might_fault+0x13a/0x1d0 mm/memory.c:4502 _copy_to_user+0x2c/0xc0 lib/usercopy.c:24 copy_to_user include/linux/uaccess.h:154 [inline] filldir+0x1a7/0x320 fs/readdir.c:196 dir_emit_dot include/linux/fs.h:3341 [inline] dir_emit_dots include/linux/fs.h:3352 [inline] dcache_readdir+0x12d/0x5e0 fs/libfs.c:193 iterate_dir+0x4b2/0x5d0 fs/readdir.c:51 SYSC_getdents fs/readdir.c:231 [inline] SyS_getdents+0x225/0x450 fs/readdir.c:212 entry_SYSCALL_64_fastpath+0x1f/0xbe -> #6 (&sb->s_type->i_mutex_key#5){++++}: down_write+0x87/0x120 kernel/locking/rwsem.c:53 inode_lock include/linux/fs.h:712 [inline] handle_create+0x30c/0x760 drivers/base/devtmpfs.c:219 handle drivers/base/devtmpfs.c:373 [inline] devtmpfsd+0x3eb/0x520 drivers/base/devtmpfs.c:399 kthread+0x39c/0x470 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 -> #5 ((complete)&req.done){+.+.}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 complete_acquire include/linux/completion.h:39 [inline] __wait_for_common kernel/sched/completion.c:108 [inline] wait_for_common kernel/sched/completion.c:122 [inline] wait_for_completion+0xc8/0x770 kernel/sched/completion.c:143 devtmpfs_create_node+0x32b/0x4a0 drivers/base/devtmpfs.c:115 device_add+0x120f/0x1640 drivers/base/core.c:1824 device_create_groups_vargs+0x1f3/0x250 drivers/base/core.c:2430 device_create_vargs drivers/base/core.c:2470 [inline] device_create+0xda/0x110 drivers/base/core.c:2506 msr_device_create+0x26/0x40 arch/x86/kernel/msr.c:188 cpuhp_invoke_callback+0x256/0x14d0 kernel/cpu.c:145 cpuhp_thread_fun+0x265/0x520 kernel/cpu.c:434 smpboot_thread_fn+0x489/0x850 kernel/smpboot.c:164 kthread+0x39c/0x470 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 -> #4 (cpuhp_state){+.+.}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 cpuhp_invoke_ap_callback kernel/cpu.c:467 [inline] cpuhp_issue_call+0x1a2/0x3e0 kernel/cpu.c:1308 __cpuhp_setup_state_cpuslocked+0x2d6/0x5f0 kernel/cpu.c:1455 __cpuhp_setup_state+0xb0/0x140 kernel/cpu.c:1484 cpuhp_setup_state include/linux/cpuhotplug.h:177 [inline] page_writeback_init+0x4d/0x71 mm/page-writeback.c:2082 pagecache_init+0x48/0x4f mm/filemap.c:871 start_kernel+0x6c1/0x754 init/main.c:690 x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:377 x86_64_start_kernel+0x77/0x7a arch/x86/kernel/head64.c:358 verify_cpu+0x0/0xfb -> #3 (cpuhp_state_mutex){+.+.}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1870 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __cpuhp_setup_state_cpuslocked+0x5b/0x5f0 kernel/cpu.c:1430 __cpuhp_setup_state+0xb0/0x140 kernel/cpu.c:1484 cpuhp_setup_state_nocalls include/linux/cpuhotplug.h:205 [inline] kvm_guest_init+0x1f3/0x20f arch/x86/kernel/kvm.c:488 setup_arch+0x1879/0x1a93 arch/x86/kernel/setup.c:1298 start_kernel+0xa5/0x754 init/main.c:530 x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:377 x86_64_start_kernel+0x77/0x7a arch/x86/kernel/head64.c:358 verify_cpu+0x0/0xfb -> #2 (cpu_hotplug_lock.rw_sem){++++}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:35 [inline] percpu_down_read include/linux/percpu-rwsem.h:58 [inline] cpus_read_lock+0x42/0x90 kernel/cpu.c:218 static_key_slow_inc+0x9d/0x3c0 kernel/jump_label.c:123 tracepoint_add_func kernel/tracepoint.c:223 [inline] tracepoint_probe_register_prio+0x80d/0x9a0 kernel/tracepoint.c:283 tracepoint_probe_register+0x2a/0x40 kernel/tracepoint.c:304 trace_event_reg+0x167/0x320 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+0x4f9/0xab0 kernel/trace/trace_event_perf.c:221 perf_tp_event_init+0x7d/0xf0 kernel/events/core.c:8037 perf_try_init_event+0xc9/0x1f0 kernel/events/core.c:9261 perf_init_event kernel/events/core.c:9299 [inline] perf_event_alloc+0x1c5b/0x2a00 kernel/events/core.c:9558 SYSC_perf_event_open+0x84e/0x2e00 kernel/events/core.c:10013 SyS_perf_event_open+0x39/0x50 kernel/events/core.c:9899 entry_SYSCALL_64_fastpath+0x1f/0xbe -> #1 (tracepoints_mutex){+.+.}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1870 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 tracepoint_probe_register_prio+0xa0/0x9a0 kernel/tracepoint.c:279 tracepoint_probe_register+0x2a/0x40 kernel/tracepoint.c:304 trace_event_reg+0x167/0x320 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+0x4f9/0xab0 kernel/trace/trace_event_perf.c:221 perf_tp_event_init+0x7d/0xf0 kernel/events/core.c:8037 perf_try_init_event+0xc9/0x1f0 kernel/events/core.c:9261 perf_init_event kernel/events/core.c:9299 [inline] perf_event_alloc+0x1c5b/0x2a00 kernel/events/core.c:9558 SYSC_perf_event_open+0x84e/0x2e00 kernel/events/core.c:10013 SyS_perf_event_open+0x39/0x50 kernel/events/core.c:9899 entry_SYSCALL_64_fastpath+0x1f/0xbe -> #0 (event_mutex){+.+.}: check_prev_add+0x865/0x1520 kernel/locking/lockdep.c:1894 check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1870 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 perf_trace_destroy+0x28/0x100 kernel/trace/trace_event_perf.c:234 tp_perf_event_destroy+0x15/0x20 kernel/events/core.c:8021 _free_event+0x401/0x1130 kernel/events/core.c:4193 put_event+0x24/0x30 kernel/events/core.c:4276 perf_mmap_close+0x60d/0xf90 kernel/events/core.c:5224 remove_vma+0xb4/0x1b0 mm/mmap.c:172 remove_vma_list mm/mmap.c:2475 [inline] do_munmap+0x82a/0xdf0 mm/mmap.c:2714 mmap_region+0x59e/0x15a0 mm/mmap.c:1631 do_mmap+0x6a1/0xd50 mm/mmap.c:1468 do_mmap_pgoff include/linux/mm.h:2151 [inline] vm_mmap_pgoff+0x1de/0x280 mm/util.c:333 SYSC_mmap_pgoff mm/mmap.c:1518 [inline] SyS_mmap_pgoff+0x23b/0x5f0 mm/mmap.c:1476 SYSC_mmap arch/x86/kernel/sys_x86_64.c:99 [inline] SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:90 entry_SYSCALL_64_fastpath+0x1f/0xbe other info that might help us debug this: Chain exists of: event_mutex --> &sb->s_type->i_mutex_key#5 --> &mm->mmap_sem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&mm->mmap_sem); lock(&sb->s_type->i_mutex_key#5); lock(&mm->mmap_sem); lock(event_mutex); *** DEADLOCK *** 1 lock held by syz-executor0/3135: #0: (&mm->mmap_sem){++++}, at: [] vm_mmap_pgoff+0x198/0x280 mm/util.c:331 stack backtrace: CPU: 1 PID: 3135 Comm: syz-executor0 Not tainted 4.13.0-mm1+ #7 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 print_circular_bug+0x503/0x710 kernel/locking/lockdep.c:1259 check_prev_add+0x865/0x1520 kernel/locking/lockdep.c:1894 check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x328f/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1870 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 perf_trace_destroy+0x28/0x100 kernel/trace/trace_event_perf.c:234 tp_perf_event_destroy+0x15/0x20 kernel/events/core.c:8021 _free_event+0x401/0x1130 kernel/events/core.c:4193 put_event+0x24/0x30 kernel/events/core.c:4276 perf_mmap_close+0x60d/0xf90 kernel/events/core.c:5224