====================================================== WARNING: possible circular locking dependency detected 6.4.0-rc3-syzkaller-00004-g421ca22e3138 #0 Not tainted ------------------------------------------------------ swapper/0/0 is trying to acquire lock: ffff88807ffdaba0 (&pgdat->kswapd_wait){-...}-{2:2}, at: __wake_up_common_lock+0xb8/0x140 kernel/sched/wait.c:137 but task is already holding lock: ffff88802c62b858 (hrtimer_bases.lock){-.-.}-{2:2}, at: __run_hrtimer kernel/time/hrtimer.c:1689 [inline] ffff88802c62b858 (hrtimer_bases.lock){-.-.}-{2:2}, at: __hrtimer_run_queues+0x23e/0xbe0 kernel/time/hrtimer.c:1749 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (hrtimer_bases.lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 lock_hrtimer_base kernel/time/hrtimer.c:173 [inline] hrtimer_start_range_ns+0xe9/0xd80 kernel/time/hrtimer.c:1296 hrtimer_start_expires include/linux/hrtimer.h:432 [inline] do_start_rt_bandwidth kernel/sched/rt.c:116 [inline] start_rt_bandwidth kernel/sched/rt.c:127 [inline] inc_rt_group kernel/sched/rt.c:1241 [inline] inc_rt_tasks kernel/sched/rt.c:1285 [inline] __enqueue_rt_entity kernel/sched/rt.c:1461 [inline] enqueue_rt_entity kernel/sched/rt.c:1510 [inline] enqueue_task_rt+0xa86/0xfc0 kernel/sched/rt.c:1545 enqueue_task+0xad/0x330 kernel/sched/core.c:2082 __sched_setscheduler.constprop.0+0xb89/0x25d0 kernel/sched/core.c:7774 _sched_setscheduler kernel/sched/core.c:7820 [inline] sched_setscheduler_nocheck kernel/sched/core.c:7867 [inline] sched_set_fifo+0xb1/0x110 kernel/sched/core.c:7891 irq_thread+0xe3/0x540 kernel/irq/manage.c:1302 kthread+0x344/0x440 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 -> #3 (&rt_b->rt_runtime_lock){-.-.}-{2:2}: __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 __enable_runtime kernel/sched/rt.c:876 [inline] rq_online_rt+0xb3/0x3b0 kernel/sched/rt.c:2485 set_rq_online.part.0+0xf9/0x140 kernel/sched/core.c:9541 set_rq_online kernel/sched/core.c:9533 [inline] sched_cpu_activate+0x216/0x440 kernel/sched/core.c:9649 cpuhp_invoke_callback+0x645/0xeb0 kernel/cpu.c:192 cpuhp_thread_fun+0x47f/0x700 kernel/cpu.c:815 smpboot_thread_fn+0x659/0x9e0 kernel/smpboot.c:164 kthread+0x344/0x440 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 -> #2 (&rq->__lock){-.-.}-{2:2}: _raw_spin_lock_nested+0x34/0x40 kernel/locking/spinlock.c:378 raw_spin_rq_lock_nested+0x2f/0x120 kernel/sched/core.c:558 raw_spin_rq_lock kernel/sched/sched.h:1366 [inline] rq_lock kernel/sched/sched.h:1653 [inline] task_fork_fair+0x74/0x4f0 kernel/sched/fair.c:12095 sched_cgroup_fork+0x3d1/0x540 kernel/sched/core.c:4777 copy_process+0x4b8a/0x7600 kernel/fork.c:2618 kernel_clone+0xeb/0x890 kernel/fork.c:2918 user_mode_thread+0xb1/0xf0 kernel/fork.c:2996 rest_init+0x27/0x2b0 init/main.c:700 arch_call_rest_init+0x13/0x30 init/main.c:834 start_kernel+0x3b6/0x490 init/main.c:1088 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:556 x86_64_start_kernel+0xb3/0xc0 arch/x86/kernel/head64.c:537 secondary_startup_64_no_verify+0xf4/0xfb -> #1 (&p->pi_lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 try_to_wake_up+0xab/0x1c40 kernel/sched/core.c:4191 autoremove_wake_function+0x16/0x150 kernel/sched/wait.c:419 __wake_up_common+0x147/0x650 kernel/sched/wait.c:107 __wake_up_common_lock+0xd4/0x140 kernel/sched/wait.c:138 wakeup_kswapd+0x3fe/0x5c0 mm/vmscan.c:7798 rmqueue mm/page_alloc.c:3057 [inline] get_page_from_freelist+0x6c5/0x2c00 mm/page_alloc.c:3499 __alloc_pages+0x1cb/0x4a0 mm/page_alloc.c:4768 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2279 skb_page_frag_refill net/core/sock.c:2854 [inline] skb_page_frag_refill+0x195/0x360 net/core/sock.c:2838 sk_page_frag_refill+0x58/0x300 net/core/sock.c:2874 tcp_sendmsg_locked+0x8c8/0x2960 net/ipv4/tcp.c:1356 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1487 inet_sendmsg+0x9d/0xe0 net/ipv4/af_inet.c:825 sock_sendmsg_nosec net/socket.c:724 [inline] sock_sendmsg+0xde/0x190 net/socket.c:747 sock_write_iter+0x295/0x3d0 net/socket.c:1140 call_write_iter include/linux/fs.h:1868 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x945/0xd50 fs/read_write.c:584 ksys_write+0x1ec/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #0 (&pgdat->kswapd_wait){-...}-{2:2}: check_prev_add kernel/locking/lockdep.c:3108 [inline] check_prevs_add kernel/locking/lockdep.c:3227 [inline] validate_chain kernel/locking/lockdep.c:3842 [inline] __lock_acquire+0x2f21/0x5df0 kernel/locking/lockdep.c:5074 lock_acquire kernel/locking/lockdep.c:5691 [inline] lock_acquire+0x1b1/0x520 kernel/locking/lockdep.c:5656 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 __wake_up_common_lock+0xb8/0x140 kernel/sched/wait.c:137 wakeup_kswapd+0x3fe/0x5c0 mm/vmscan.c:7798 wake_all_kswapds+0x182/0x2d0 mm/page_alloc.c:4028 __alloc_pages_slowpath.constprop.0+0x1724/0x2170 mm/page_alloc.c:4296 __alloc_pages+0x408/0x4a0 mm/page_alloc.c:4781 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2279 alloc_slab_page mm/slub.c:1851 [inline] allocate_slab+0x25f/0x390 mm/slub.c:1998 new_slab mm/slub.c:2051 [inline] ___slab_alloc+0xa91/0x1400 mm/slub.c:3192 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3291 __slab_alloc_node mm/slub.c:3344 [inline] slab_alloc_node mm/slub.c:3441 [inline] slab_alloc mm/slub.c:3459 [inline] __kmem_cache_alloc_lru mm/slub.c:3466 [inline] kmem_cache_alloc+0x38e/0x3b0 mm/slub.c:3475 kmem_cache_zalloc include/linux/slab.h:670 [inline] fill_pool+0x264/0x5c0 lib/debugobjects.c:168 debug_objects_fill_pool lib/debugobjects.c:597 [inline] debug_object_activate+0xfd/0x400 lib/debugobjects.c:693 debug_hrtimer_activate kernel/time/hrtimer.c:420 [inline] debug_activate kernel/time/hrtimer.c:475 [inline] enqueue_hrtimer+0x27/0x320 kernel/time/hrtimer.c:1084 __run_hrtimer kernel/time/hrtimer.c:1702 [inline] __hrtimer_run_queues+0xa5b/0xbe0 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x320/0x7b0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1095 [inline] __sysvec_apic_timer_interrupt+0x14a/0x430 arch/x86/kernel/apic/apic.c:1112 sysvec_apic_timer_interrupt+0x92/0xc0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] arch_safe_halt arch/x86/include/asm/irqflags.h:86 [inline] default_idle+0xf/0x20 arch/x86/kernel/process.c:710 default_idle_call+0x67/0xa0 kernel/sched/idle.c:97 cpuidle_idle_call kernel/sched/idle.c:170 [inline] do_idle+0x317/0x3c0 kernel/sched/idle.c:282 cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:379 rest_init+0x16f/0x2b0 init/main.c:735 arch_call_rest_init+0x13/0x30 init/main.c:834 start_kernel+0x3b6/0x490 init/main.c:1088 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:556 x86_64_start_kernel+0xb3/0xc0 arch/x86/kernel/head64.c:537 secondary_startup_64_no_verify+0xf4/0xfb other info that might help us debug this: Chain exists of: &pgdat->kswapd_wait --> &rt_b->rt_runtime_lock --> hrtimer_bases.lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(hrtimer_bases.lock); lock(&rt_b->rt_runtime_lock); lock(hrtimer_bases.lock); lock(&pgdat->kswapd_wait); *** DEADLOCK *** 1 lock held by swapper/0/0: #0: ffff88802c62b858 (hrtimer_bases.lock){-.-.}-{2:2}, at: __run_hrtimer kernel/time/hrtimer.c:1689 [inline] #0: ffff88802c62b858 (hrtimer_bases.lock){-.-.}-{2:2}, at: __hrtimer_run_queues+0x23e/0xbe0 kernel/time/hrtimer.c:1749 stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.4.0-rc3-syzkaller-00004-g421ca22e3138 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2188 check_prev_add kernel/locking/lockdep.c:3108 [inline] check_prevs_add kernel/locking/lockdep.c:3227 [inline] validate_chain kernel/locking/lockdep.c:3842 [inline] __lock_acquire+0x2f21/0x5df0 kernel/locking/lockdep.c:5074 lock_acquire kernel/locking/lockdep.c:5691 [inline] lock_acquire+0x1b1/0x520 kernel/locking/lockdep.c:5656 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 __wake_up_common_lock+0xb8/0x140 kernel/sched/wait.c:137 wakeup_kswapd+0x3fe/0x5c0 mm/vmscan.c:7798 wake_all_kswapds+0x182/0x2d0 mm/page_alloc.c:4028 __alloc_pages_slowpath.constprop.0+0x1724/0x2170 mm/page_alloc.c:4296 __alloc_pages+0x408/0x4a0 mm/page_alloc.c:4781 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2279 alloc_slab_page mm/slub.c:1851 [inline] allocate_slab+0x25f/0x390 mm/slub.c:1998 new_slab mm/slub.c:2051 [inline] ___slab_alloc+0xa91/0x1400 mm/slub.c:3192 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3291 __slab_alloc_node mm/slub.c:3344 [inline] slab_alloc_node mm/slub.c:3441 [inline] slab_alloc mm/slub.c:3459 [inline] __kmem_cache_alloc_lru mm/slub.c:3466 [inline] kmem_cache_alloc+0x38e/0x3b0 mm/slub.c:3475 kmem_cache_zalloc include/linux/slab.h:670 [inline] fill_pool+0x264/0x5c0 lib/debugobjects.c:168 debug_objects_fill_pool lib/debugobjects.c:597 [inline] debug_object_activate+0xfd/0x400 lib/debugobjects.c:693 debug_hrtimer_activate kernel/time/hrtimer.c:420 [inline] debug_activate kernel/time/hrtimer.c:475 [inline] enqueue_hrtimer+0x27/0x320 kernel/time/hrtimer.c:1084 __run_hrtimer kernel/time/hrtimer.c:1702 [inline] __hrtimer_run_queues+0xa5b/0xbe0 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x320/0x7b0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1095 [inline] __sysvec_apic_timer_interrupt+0x14a/0x430 arch/x86/kernel/apic/apic.c:1112 sysvec_apic_timer_interrupt+0x92/0xc0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline] RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:72 [inline] RIP: 0010:default_idle+0xf/0x20 arch/x86/kernel/process.c:711 Code: 89 07 49 c7 c0 08 00 00 00 4d 29 c8 4c 01 c7 4c 29 c2 e9 76 ff ff ff cc cc cc cc f3 0f 1e fa 66 90 0f 00 2d 83 e9 36 00 fb f4 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 f3 0f 1e fa 65 RSP: 0018:ffffffff8c407e08 EFLAGS: 00000246 RAX: 00000000001724f3 RBX: 0000000000000000 RCX: ffffffff8a0f94e5 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: dffffc0000000000 R08: 0000000000000001 R09: ffff88802c636ceb R10: ffffed10058c6d9d R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff8e7a7810 R14: 0000000000000000 R15: 0000000000000000 default_idle_call+0x67/0xa0 kernel/sched/idle.c:97 cpuidle_idle_call kernel/sched/idle.c:170 [inline] do_idle+0x317/0x3c0 kernel/sched/idle.c:282 cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:379 rest_init+0x16f/0x2b0 init/main.c:735 arch_call_rest_init+0x13/0x30 init/main.c:834 start_kernel+0x3b6/0x490 init/main.c:1088 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:556 x86_64_start_kernel+0xb3/0xc0 arch/x86/kernel/head64.c:537 secondary_startup_64_no_verify+0xf4/0xfb ---------------- Code disassembly (best guess): 0: 89 07 mov %eax,(%rdi) 2: 49 c7 c0 08 00 00 00 mov $0x8,%r8 9: 4d 29 c8 sub %r9,%r8 c: 4c 01 c7 add %r8,%rdi f: 4c 29 c2 sub %r8,%rdx 12: e9 76 ff ff ff jmpq 0xffffff8d 17: cc int3 18: cc int3 19: cc int3 1a: cc int3 1b: f3 0f 1e fa endbr64 1f: 66 90 xchg %ax,%ax 21: 0f 00 2d 83 e9 36 00 verw 0x36e983(%rip) # 0x36e9ab 28: fb sti 29: f4 hlt * 2a: fa cli <-- trapping instruction 2b: c3 retq 2c: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1) 33: 00 00 00 00 37: 0f 1f 40 00 nopl 0x0(%rax) 3b: f3 0f 1e fa endbr64 3f: 65 gs