====================================================== WARNING: possible circular locking dependency detected 5.6.0-rc3-next-20200228-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor943/9717 is trying to acquire lock: ffffffff8996a1e0 (cpu_hotplug_lock){++++}, at: __static_key_slow_dec kernel/jump_label.c:254 [inline] ffffffff8996a1e0 (cpu_hotplug_lock){++++}, at: static_key_slow_dec+0x4f/0x90 kernel/jump_label.c:270 but task is already holding lock: ffff88808bbdee58 (&mm->mmap_sem#2){++++}, at: vm_mmap_pgoff+0x152/0x200 mm/util.c:504 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&mm->mmap_sem#2){++++}: down_write+0x8d/0x150 kernel/locking/rwsem.c:1531 mpol_rebind_mm+0x20/0xc0 mm/mempolicy.c:408 cpuset_attach+0x214/0x400 kernel/cgroup/cpuset.c:2203 cgroup_migrate_execute+0xc34/0x1210 kernel/cgroup/cgroup.c:2446 cgroup_attach_task+0x480/0x880 kernel/cgroup/cgroup.c:2735 __cgroup1_procs_write.constprop.0+0x3a7/0x490 kernel/cgroup/cgroup-v1.c:522 cgroup_file_write+0x20d/0x710 kernel/cgroup/cgroup.c:3692 kernfs_fop_write+0x268/0x490 fs/kernfs/file.c:315 __vfs_write+0x76/0x100 fs/read_write.c:494 vfs_write+0x262/0x5c0 fs/read_write.c:558 ksys_write+0x127/0x250 fs/read_write.c:611 do_syscall_64+0xf6/0x790 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&cpuset_rwsem){++++}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] cpuset_read_lock+0x3b/0x140 kernel/cgroup/cpuset.c:340 __sched_setscheduler.constprop.0+0x251/0x2000 kernel/sched/core.c:4867 _sched_setscheduler+0xee/0x180 kernel/sched/core.c:5039 __kthread_create_on_node+0x2ea/0x410 kernel/kthread.c:349 kthread_create_on_node+0xbb/0xf0 kernel/kthread.c:388 create_worker+0x23b/0x530 kernel/workqueue.c:1926 workqueue_prepare_cpu+0x9c/0xf0 kernel/workqueue.c:5026 cpuhp_invoke_callback+0x22c/0x1d20 kernel/cpu.c:172 cpuhp_up_callbacks kernel/cpu.c:599 [inline] _cpu_up+0x27d/0x540 kernel/cpu.c:1165 do_cpu_up kernel/cpu.c:1200 [inline] do_cpu_up+0xfe/0x1a0 kernel/cpu.c:1172 smp_init+0x239/0x24e kernel/smp.c:604 kernel_init_freeable+0x32e/0x5ae init/main.c:1442 kernel_init+0xd/0x1bb init/main.c:1355 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 -> #0 (cpu_hotplug_lock){++++}: check_prev_add kernel/locking/lockdep.c:2481 [inline] check_prevs_add kernel/locking/lockdep.c:2586 [inline] validate_chain kernel/locking/lockdep.c:3203 [inline] __lock_acquire+0x24b3/0x5270 kernel/locking/lockdep.c:4190 lock_acquire+0x197/0x420 kernel/locking/lockdep.c:4720 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] cpus_read_lock+0x3b/0x140 kernel/cpu.c:292 __static_key_slow_dec kernel/jump_label.c:254 [inline] static_key_slow_dec+0x4f/0x90 kernel/jump_label.c:270 sw_perf_event_destroy+0x81/0x130 kernel/events/core.c:8851 _free_event+0x33b/0x1270 kernel/events/core.c:4617 put_event+0x40/0x50 kernel/events/core.c:4711 perf_mmap_close+0x6fb/0xd40 kernel/events/core.c:5755 remove_vma+0xa9/0x170 mm/mmap.c:177 remove_vma_list mm/mmap.c:2582 [inline] __do_munmap+0x729/0x10e0 mm/mmap.c:2826 do_munmap mm/mmap.c:2834 [inline] mmap_region+0x1ef/0x1530 mm/mmap.c:1713 do_mmap+0x843/0x1140 mm/mmap.c:1543 do_mmap_pgoff include/linux/mm.h:2418 [inline] vm_mmap_pgoff+0x197/0x200 mm/util.c:506 ksys_mmap_pgoff+0x457/0x5b0 mm/mmap.c:1593 do_syscall_64+0xf6/0x790 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &cpuset_rwsem --> &mm->mmap_sem#2 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&mm->mmap_sem#2); lock(&cpuset_rwsem); lock(&mm->mmap_sem#2); lock(cpu_hotplug_lock); *** DEADLOCK *** 1 lock held by syz-executor943/9717: #0: ffff88808bbdee58 (&mm->mmap_sem#2){++++}, at: vm_mmap_pgoff+0x152/0x200 mm/util.c:504 stack backtrace: CPU: 1 PID: 9717 Comm: syz-executor943 Not tainted 5.6.0-rc3-next-20200228-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 check_noncircular+0x32e/0x3e0 kernel/locking/lockdep.c:1812 check_prev_add kernel/locking/lockdep.c:2481 [inline] check_prevs_add kernel/locking/lockdep.c:2586 [inline] validate_chain kernel/locking/lockdep.c:3203 [inline] __lock_acquire+0x24b3/0x5270 kernel/locking/lockdep.c:4190 lock_acquire+0x197/0x420 kernel/locking/lockdep.c:4720 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] cpus_read_lock+0x3b/0x140 kernel/cpu.c:292 __static_key_slow_dec kernel/jump_label.c:254 [inline] static_key_slow_dec+0x4f/0x90 kernel/jump_label.c:270 sw_perf_event_destroy+0x81/0x130 kernel/events/core.c:8851 _free_event+0x33b/0x1270 kernel/events/core.c:4617 put_event+0x40/0x50 kernel/events/core.c:4711 perf_mmap_close+0x6fb/0xd40 kernel/events/core.c:5755 remove_vma+0xa9/0x170 mm/mmap.c:177 remove_vma_list mm/mmap.c:2582 [inline] __do_munmap+0x729/0x10e0 mm/mmap.c:2826 do_munmap mm/mmap.c:2834 [inline] mmap_region+0x1ef/0x1530 mm/mmap.c:1713 do_mmap+0x843/0x1140 mm/mmap.c:1543 do_mmap_pgoff include/linux/mm.h:2418 [inline] vm_mmap_pgoff+0x197/0x200 mm/util.c:506 ksys_mmap_pgoff+0x457/0x5b0 mm/mmap.c:1593 do_syscall_64+0xf6/0x790 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4472e9 Code: e8 2c bb 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 5b 07 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f2fc7de5da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00000000006dcc38 RCX: 00000000004472e9 RDX: 0000000000000000 RSI: 0000000000003000 RDI: 0000000020ffd000 RBP: 00000000006dcc30 R08: 0000000000000004 R09: 0000000000000000 R10: 0000000000000011 R11: 0000000000000246 R12: 00000000006dcc3c R13: 00007fff00f092af R14: 00007f2fc7de69c0 R15: 0000000000000000