====================================================== WARNING: possible circular locking dependency detected 5.14.0-rc1-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.2/8508 is trying to acquire lock: ffffffff8ba9af80 (fs_reclaim){+.+.}-{0:0}, at: fs_reclaim_acquire+0xf7/0x160 mm/page_alloc.c:4574 but task is already holding lock: ffff8880b9d4d580 (lock#2){-.-.}-{2:2}, at: __alloc_pages_bulk+0x4ad/0x1870 mm/page_alloc.c:5279 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (lock#2){-.-.}-{2:2}: local_lock_acquire include/linux/local_lock_internal.h:42 [inline] free_unref_page+0x1bf/0x690 mm/page_alloc.c:3427 mm_free_pgd kernel/fork.c:636 [inline] __mmdrop+0xcb/0x3f0 kernel/fork.c:687 mmdrop include/linux/sched/mm.h:49 [inline] finish_task_switch.isra.0+0x6da/0xa50 kernel/sched/core.c:4582 context_switch kernel/sched/core.c:4686 [inline] __schedule+0x942/0x26f0 kernel/sched/core.c:5940 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:6328 irqentry_exit+0x31/0x80 kernel/entry/common.c:427 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:629 fs_reclaim_release+0x9c/0xf0 mm/page_alloc.c:4585 prepare_alloc_pages+0x164/0x580 mm/page_alloc.c:5165 __alloc_pages+0x12f/0x500 mm/page_alloc.c:5363 alloc_pages_vma+0xd9/0x710 mm/mempolicy.c:2208 do_anonymous_page mm/memory.c:3767 [inline] handle_pte_fault mm/memory.c:4547 [inline] __handle_mm_fault+0x1f67/0x5320 mm/memory.c:4684 handle_mm_fault+0x1c8/0x790 mm/memory.c:4782 do_user_addr_fault+0x48b/0x11c0 arch/x86/mm/fault.c:1390 handle_page_fault arch/x86/mm/fault.c:1475 [inline] exc_page_fault+0x9e/0x180 arch/x86/mm/fault.c:1531 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:568 -> #0 (fs_reclaim){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add kernel/locking/lockdep.c:3174 [inline] validate_chain kernel/locking/lockdep.c:3789 [inline] __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015 lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 __fs_reclaim_acquire mm/page_alloc.c:4552 [inline] fs_reclaim_acquire+0x117/0x160 mm/page_alloc.c:4566 prepare_alloc_pages+0x15c/0x580 mm/page_alloc.c:5164 __alloc_pages+0x12f/0x500 mm/page_alloc.c:5363 alloc_pages+0x18c/0x2a0 mm/mempolicy.c:2244 stack_depot_save+0x39d/0x4e0 lib/stackdepot.c:303 save_stack+0x15e/0x1e0 mm/page_owner.c:120 __set_page_owner+0x50/0x290 mm/page_owner.c:181 prep_new_page mm/page_alloc.c:2433 [inline] __alloc_pages_bulk+0x8b9/0x1870 mm/page_alloc.c:5301 alloc_pages_bulk_array_node include/linux/gfp.h:557 [inline] vm_area_alloc_pages mm/vmalloc.c:2793 [inline] __vmalloc_area_node mm/vmalloc.c:2863 [inline] __vmalloc_node_range+0x39d/0x960 mm/vmalloc.c:2966 __vmalloc_node mm/vmalloc.c:3015 [inline] __vmalloc+0x69/0x80 mm/vmalloc.c:3029 pcpu_mem_zalloc mm/percpu.c:517 [inline] pcpu_mem_zalloc+0x51/0xa0 mm/percpu.c:509 pcpu_alloc_chunk mm/percpu.c:1465 [inline] pcpu_create_chunk+0x18a/0x720 mm/percpu-vm.c:338 pcpu_alloc+0xfa1/0x1350 mm/percpu.c:1838 xt_percpu_counter_alloc+0x131/0x1a0 net/netfilter/x_tables.c:1869 find_check_entry.constprop.0+0xab/0x9a0 net/ipv4/netfilter/ip_tables.c:527 translate_table+0xc26/0x16a0 net/ipv4/netfilter/ip_tables.c:717 ipt_register_table+0x10c/0x360 net/ipv4/netfilter/ip_tables.c:1736 iptable_raw_table_init+0x61/0x90 net/ipv4/netfilter/iptable_raw.c:61 xt_find_table_lock+0x44e/0xaf0 net/netfilter/x_tables.c:1244 xt_request_find_table_lock+0x27/0xf0 net/netfilter/x_tables.c:1275 get_info+0x16a/0x740 net/ipv6/netfilter/ip6_tables.c:980 do_ipt_get_ctl+0x152/0x9d0 net/ipv4/netfilter/ip_tables.c:1653 nf_getsockopt+0x72/0xd0 net/netfilter/nf_sockopt.c:116 ip_getsockopt net/ipv4/ip_sockglue.c:1777 [inline] ip_getsockopt+0x164/0x1c0 net/ipv4/ip_sockglue.c:1756 tcp_getsockopt+0x86/0xd0 net/ipv4/tcp.c:4253 __sys_getsockopt+0x21f/0x5f0 net/socket.c:2203 __do_sys_getsockopt net/socket.c:2218 [inline] __se_sys_getsockopt net/socket.c:2215 [inline] __x64_sys_getsockopt+0xba/0x150 net/socket.c:2215 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(lock#2); lock(fs_reclaim); lock(lock#2); lock(fs_reclaim); *** DEADLOCK *** 2 locks held by syz-executor.2/8508: #0: ffffffff8ba7b9c8 (pcpu_alloc_mutex){+.+.}-{3:3}, at: pcpu_alloc+0xb12/0x1350 mm/percpu.c:1778 #1: ffff8880b9d4d580 (lock#2){-.-.}-{2:2}, at: __alloc_pages_bulk+0x4ad/0x1870 mm/page_alloc.c:5279 stack backtrace: CPU: 1 PID: 8508 Comm: syz-executor.2 Not tainted 5.14.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2131 check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add kernel/locking/lockdep.c:3174 [inline] validate_chain kernel/locking/lockdep.c:3789 [inline] __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015 lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 __fs_reclaim_acquire mm/page_alloc.c:4552 [inline] fs_reclaim_acquire+0x117/0x160 mm/page_alloc.c:4566 prepare_alloc_pages+0x15c/0x580 mm/page_alloc.c:5164 __alloc_pages+0x12f/0x500 mm/page_alloc.c:5363 alloc_pages+0x18c/0x2a0 mm/mempolicy.c:2244 stack_depot_save+0x39d/0x4e0 lib/stackdepot.c:303 save_stack+0x15e/0x1e0 mm/page_owner.c:120