===================================================== WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected syzkaller #0 Not tainted ----------------------------------------------------- syz.4.21/6846 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: ffff800097625150 (&p->sequence){+.-.}-{0:0}, at: __fprop_add_percpu_max+0x130/0x1f4 lib/flex_proportions.c:186 and this task is already holding: ffff0000f7d10240 (&xa->xa_lock#10){-.-.}-{3:3}, at: __folio_end_writeback+0x10c/0x6f8 mm/page-writeback.c:2990 which would create a new lock dependency: (&xa->xa_lock#10){-.-.}-{3:3} -> (&p->sequence){+.-.}-{0:0} but this new dependency connects a HARDIRQ-irq-safe lock: (&xa->xa_lock#10){-.-.}-{3:3} ... which became HARDIRQ-irq-safe at: lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x5c/0x7c kernel/locking/spinlock.c:162 __folio_end_writeback+0x10c/0x6f8 mm/page-writeback.c:2990 folio_end_writeback_no_dropbehind+0xd0/0x204 mm/filemap.c:1661 folio_end_writeback+0xd8/0x248 mm/filemap.c:1687 end_buffer_async_write+0x20c/0x350 fs/buffer.c:419 end_bio_bh_io_sync+0xb0/0x184 fs/buffer.c:2776 bio_endio+0x8d4/0x910 block/bio.c:1675 blk_complete_request block/blk-mq.c:908 [inline] blk_mq_end_request_batch+0x49c/0x105c block/blk-mq.c:1202 nvme_complete_batch drivers/nvme/host/nvme.h:802 [inline] nvme_pci_complete_batch drivers/nvme/host/pci.c:1348 [inline] nvme_irq+0x1ec/0x240 drivers/nvme/host/pci.c:1450 __handle_irq_event_percpu+0x20c/0x8e4 kernel/irq/handle.c:211 handle_irq_event_percpu kernel/irq/handle.c:248 [inline] handle_irq_event+0x9c/0x1d0 kernel/irq/handle.c:265 handle_fasteoi_irq+0x328/0x8d8 kernel/irq/chip.c:764 generic_handle_irq_desc include/linux/irqdesc.h:172 [inline] handle_irq_desc kernel/irq/irqdesc.c:669 [inline] generic_handle_domain_irq+0xe0/0x140 kernel/irq/irqdesc.c:725 __gic_handle_irq drivers/irqchip/irq-gic-v3.c:825 [inline] __gic_handle_irq_from_irqson drivers/irqchip/irq-gic-v3.c:876 [inline] gic_handle_irq+0x6c/0x18c drivers/irqchip/irq-gic-v3.c:920 do_interrupt_handler+0xe0/0x138 arch/arm64/kernel/entry-common.c:137 __el1_irq arch/arm64/kernel/entry-common.c:497 [inline] el1_interrupt+0x3c/0x60 arch/arm64/kernel/entry-common.c:510 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:515 el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:592 __daif_local_irq_restore arch/arm64/include/asm/irqflags.h:175 [inline] arch_local_irq_restore+0x8/0xc arch/arm64/include/asm/irqflags.h:195 lock_is_held include/linux/lockdep.h:249 [inline] rcu_read_lock_held+0x34/0x50 kernel/rcu/update.c:351 __find_rr_leaf+0x2d4/0x5c8 net/ipv6/route.c:833 find_rr_leaf net/ipv6/route.c:889 [inline] rt6_select net/ipv6/route.c:933 [inline] fib6_table_lookup+0x308/0x8b8 net/ipv6/route.c:2233 ip6_pol_route+0x1f8/0x101c net/ipv6/route.c:2269 ip6_pol_route_input+0x74/0x94 net/ipv6/route.c:2326 pol_lookup_func include/net/ip6_fib.h:617 [inline] fib6_rule_lookup+0x174/0x45c net/ipv6/fib6_rules.c:120 ip6_route_input_lookup net/ipv6/route.c:2338 [inline] ip6_route_input+0x5d0/0x930 net/ipv6/route.c:2641 ip6_rcv_finish_core+0x218/0x3c8 net/ipv6/ip6_input.c:66 ip6_rcv_finish+0x120/0x21c net/ipv6/ip6_input.c:77 NF_HOOK+0x2c4/0x358 include/linux/netfilter.h:318 ipv6_rcv+0x9c/0xbc net/ipv6/ip6_input.c:311 __netif_receive_skb_one_core net/core/dev.c:6137 [inline] __netif_receive_skb+0xcc/0x2a8 net/core/dev.c:6250 process_backlog+0x608/0x10e8 net/core/dev.c:6602 __napi_poll+0xb0/0x310 net/core/dev.c:7666 napi_poll net/core/dev.c:7729 [inline] net_rx_action+0x548/0xcf0 net/core/dev.c:7881 handle_softirqs+0x31c/0xc88 kernel/softirq.c:622 __do_softirq+0x14/0x20 kernel/softirq.c:656 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:68 call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:891 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:73 do_softirq+0x90/0xf8 kernel/softirq.c:523 __local_bh_enable_ip+0x240/0x35c kernel/softirq.c:450 local_bh_enable+0x28/0x34 include/linux/bottom_half.h:33 rcu_read_unlock_bh include/linux/rcupdate.h:936 [inline] __dev_queue_xmit+0x1464/0x2a68 net/core/dev.c:4844 dev_queue_xmit include/linux/netdevice.h:3381 [inline] neigh_hh_output include/net/neighbour.h:540 [inline] neigh_output include/net/neighbour.h:554 [inline] ip6_finish_output2+0x1150/0x1a78 net/ipv6/ip6_output.c:136 __ip6_finish_output net/ipv6/ip6_output.c:-1 [inline] ip6_finish_output+0x418/0x7b4 net/ipv6/ip6_output.c:220 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip6_output+0x2c8/0x640 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:464 [inline] NF_HOOK+0x15c/0x430 include/linux/netfilter.h:318 mld_sendpack+0x7fc/0x100c net/ipv6/mcast.c:1855 mld_send_initial_cr+0x34c/0x534 net/ipv6/mcast.c:2271 ipv6_mc_dad_complete+0x74/0x3a8 net/ipv6/mcast.c:2279 addrconf_dad_completed+0x604/0xb74 net/ipv6/addrconf.c:4340 addrconf_dad_work+0x928/0x10cc net/ipv6/addrconf.c:-1 process_one_work+0x7c0/0x1558 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x958/0xed8 kernel/workqueue.c:3421 kthread+0x5fc/0x75c kernel/kthread.c:463 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844 to a HARDIRQ-irq-unsafe lock: (&p->sequence){+.-.}-{0:0} ... which became HARDIRQ-irq-unsafe at: ... lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868 do_write_seqcount_begin_nested include/linux/seqlock.h:477 [inline] do_write_seqcount_begin include/linux/seqlock.h:503 [inline] fprop_new_period+0x3b8/0x718 lib/flex_proportions.c:74 writeout_period+0x94/0x11c mm/page-writeback.c:615 call_timer_fn+0x19c/0x814 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers kernel/time/timer.c:2373 [inline] __run_timer_base+0x51c/0x76c kernel/time/timer.c:2385 run_timer_base kernel/time/timer.c:2394 [inline] run_timer_softirq+0x11c/0x194 kernel/time/timer.c:2405 handle_softirqs+0x31c/0xc88 kernel/softirq.c:622 __do_softirq+0x14/0x20 kernel/softirq.c:656 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:68 call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:891 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:73 invoke_softirq kernel/softirq.c:503 [inline] __irq_exit_rcu+0x1b0/0x478 kernel/softirq.c:723 irq_exit_rcu+0x14/0x84 kernel/softirq.c:739 __el1_irq arch/arm64/kernel/entry-common.c:498 [inline] el1_interrupt+0x40/0x60 arch/arm64/kernel/entry-common.c:510 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:515 el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:592 __daif_local_irq_restore arch/arm64/include/asm/irqflags.h:175 [inline] arch_local_irq_restore arch/arm64/include/asm/irqflags.h:195 [inline] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock_irqrestore+0x44/0x98 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] unlock_task_sighand include/linux/sched/signal.h:756 [inline] do_send_sig_info kernel/signal.c:1270 [inline] do_send_specific+0x1cc/0x2cc kernel/signal.c:4131 do_tkill kernel/signal.c:4152 [inline] __do_sys_tgkill kernel/signal.c:4171 [inline] __se_sys_tgkill kernel/signal.c:4165 [inline] __arm64_sys_tgkill+0x12c/0x188 kernel/signal.c:4165 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&p->sequence); local_irq_disable(); lock(&xa->xa_lock#10); lock(&p->sequence); lock(&xa->xa_lock#10); *** DEADLOCK *** 2 locks held by syz.4.21/6846: #0: ffff0000f7d10638 (&fi->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] #0: ffff0000f7d10638 (&fi->lock){+.+.}-{3:3}, at: fuse_writepages_send fs/fuse/file.c:2156 [inline] #0: ffff0000f7d10638 (&fi->lock){+.+.}-{3:3}, at: fuse_iomap_writeback_range+0x674/0x149c fs/fuse/file.c:2225 #1: ffff0000f7d10240 (&xa->xa_lock#10){-.-.}-{3:3}, at: __folio_end_writeback+0x10c/0x6f8 mm/page-writeback.c:2990 the dependencies between HARDIRQ-irq-safe lock and the holding lock: -> (&xa->xa_lock#10){-.-.}-{3:3} { IN-HARDIRQ-W at: lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x5c/0x7c kernel/locking/spinlock.c:162 __folio_end_writeback+0x10c/0x6f8 mm/page-writeback.c:2990 folio_end_writeback_no_dropbehind+0xd0/0x204 mm/filemap.c:1661 folio_end_writeback+0xd8/0x248 mm/filemap.c:1687 end_buffer_async_write+0x20c/0x350 fs/buffer.c:419 end_bio_bh_io_sync+0xb0/0x184 fs/buffer.c:2776 bio_endio+0x8d4/0x910 block/bio.c:1675 blk_complete_request block/blk-mq.c:908 [inline] blk_mq_end_request_batch+0x49c/0x105c block/blk-mq.c:1202 nvme_complete_batch drivers/nvme/host/nvme.h:802 [inline] nvme_pci_complete_batch drivers/nvme/host/pci.c:1348 [inline] nvme_irq+0x1ec/0x240 drivers/nvme/host/pci.c:1450 __handle_irq_event_percpu+0x20c/0x8e4 kernel/irq/handle.c:211 handle_irq_event_percpu kernel/irq/handle.c:248 [inline] handle_irq_event+0x9c/0x1d0 kernel/irq/handle.c:265 handle_fasteoi_irq+0x328/0x8d8 kernel/irq/chip.c:764 generic_handle_irq_desc include/linux/irqdesc.h:172 [inline] handle_irq_desc kernel/irq/irqdesc.c:669 [inline] generic_handle_domain_irq+0xe0/0x140 kernel/irq/irqdesc.c:725 __gic_handle_irq drivers/irqchip/irq-gic-v3.c:825 [inline] __gic_handle_irq_from_irqson drivers/irqchip/irq-gic-v3.c:876 [inline] gic_handle_irq+0x6c/0x18c drivers/irqchip/irq-gic-v3.c:920 do_interrupt_handler+0xe0/0x138 arch/arm64/kernel/entry-common.c:137 __el1_irq arch/arm64/kernel/entry-common.c:497 [inline] el1_interrupt+0x3c/0x60 arch/arm64/kernel/entry-common.c:510 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:515 el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:592 __daif_local_irq_restore arch/arm64/include/asm/irqflags.h:175 [inline] arch_local_irq_restore+0x8/0xc arch/arm64/include/asm/irqflags.h:195 lock_is_held include/linux/lockdep.h:249 [inline] rcu_read_lock_held+0x34/0x50 kernel/rcu/update.c:351 __find_rr_leaf+0x2d4/0x5c8 net/ipv6/route.c:833 find_rr_leaf net/ipv6/route.c:889 [inline] rt6_select net/ipv6/route.c:933 [inline] fib6_table_lookup+0x308/0x8b8 net/ipv6/route.c:2233 ip6_pol_route+0x1f8/0x101c net/ipv6/route.c:2269 ip6_pol_route_input+0x74/0x94 net/ipv6/route.c:2326 pol_lookup_func include/net/ip6_fib.h:617 [inline] fib6_rule_lookup+0x174/0x45c net/ipv6/fib6_rules.c:120 ip6_route_input_lookup net/ipv6/route.c:2338 [inline] ip6_route_input+0x5d0/0x930 net/ipv6/route.c:2641 ip6_rcv_finish_core+0x218/0x3c8 net/ipv6/ip6_input.c:66 ip6_rcv_finish+0x120/0x21c net/ipv6/ip6_input.c:77 NF_HOOK+0x2c4/0x358 include/linux/netfilter.h:318 ipv6_rcv+0x9c/0xbc net/ipv6/ip6_input.c:311 __netif_receive_skb_one_core net/core/dev.c:6137 [inline] __netif_receive_skb+0xcc/0x2a8 net/core/dev.c:6250 process_backlog+0x608/0x10e8 net/core/dev.c:6602 __napi_poll+0xb0/0x310 net/core/dev.c:7666 napi_poll net/core/dev.c:7729 [inline] net_rx_action+0x548/0xcf0 net/core/dev.c:7881 handle_softirqs+0x31c/0xc88 kernel/softirq.c:622 __do_softirq+0x14/0x20 kernel/softirq.c:656 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:68 call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:891 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:73 do_softirq+0x90/0xf8 kernel/softirq.c:523 __local_bh_enable_ip+0x240/0x35c kernel/softirq.c:450 local_bh_enable+0x28/0x34 include/linux/bottom_half.h:33 rcu_read_unlock_bh include/linux/rcupdate.h:936 [inline] __dev_queue_xmit+0x1464/0x2a68 net/core/dev.c:4844 dev_queue_xmit include/linux/netdevice.h:3381 [inline] neigh_hh_output include/net/neighbour.h:540 [inline] neigh_output include/net/neighbour.h:554 [inline] ip6_finish_output2+0x1150/0x1a78 net/ipv6/ip6_output.c:136 __ip6_finish_output net/ipv6/ip6_output.c:-1 [inline] ip6_finish_output+0x418/0x7b4 net/ipv6/ip6_output.c:220 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip6_output+0x2c8/0x640 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:464 [inline] NF_HOOK+0x15c/0x430 include/linux/netfilter.h:318 mld_sendpack+0x7fc/0x100c net/ipv6/mcast.c:1855 mld_send_initial_cr+0x34c/0x534 net/ipv6/mcast.c:2271 ipv6_mc_dad_complete+0x74/0x3a8 net/ipv6/mcast.c:2279 addrconf_dad_completed+0x604/0xb74 net/ipv6/addrconf.c:4340 addrconf_dad_work+0x928/0x10cc net/ipv6/addrconf.c:-1 process_one_work+0x7c0/0x1558 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x958/0xed8 kernel/workqueue.c:3421 kthread+0x5fc/0x75c kernel/kthread.c:463 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844 IN-SOFTIRQ-W at: lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x5c/0x7c kernel/locking/spinlock.c:162 __folio_end_writeback+0x10c/0x6f8 mm/page-writeback.c:2990 folio_end_writeback_no_dropbehind+0xd0/0x204 mm/filemap.c:1661 folio_end_writeback+0xd8/0x248 mm/filemap.c:1687 end_buffer_async_write+0x20c/0x350 fs/buffer.c:419 end_bio_bh_io_sync+0xb0/0x184 fs/buffer.c:2776 bio_endio+0x8d4/0x910 block/bio.c:1675 blk_complete_request block/blk-mq.c:908 [inline] blk_mq_end_request_batch+0x49c/0x105c block/blk-mq.c:1202 nvme_complete_batch drivers/nvme/host/nvme.h:802 [inline] nvme_pci_complete_batch drivers/nvme/host/pci.c:1348 [inline] nvme_irq+0x1ec/0x240 drivers/nvme/host/pci.c:1450 __handle_irq_event_percpu+0x20c/0x8e4 kernel/irq/handle.c:211 handle_irq_event_percpu kernel/irq/handle.c:248 [inline] handle_irq_event+0x9c/0x1d0 kernel/irq/handle.c:265 handle_fasteoi_irq+0x328/0x8d8 kernel/irq/chip.c:764 generic_handle_irq_desc include/linux/irqdesc.h:172 [inline] handle_irq_desc kernel/irq/irqdesc.c:669 [inline] generic_handle_domain_irq+0xe0/0x140 kernel/irq/irqdesc.c:725 __gic_handle_irq drivers/irqchip/irq-gic-v3.c:825 [inline] __gic_handle_irq_from_irqson drivers/irqchip/irq-gic-v3.c:876 [inline] gic_handle_irq+0x6c/0x18c drivers/irqchip/irq-gic-v3.c:920 do_interrupt_handler+0xe0/0x138 arch/arm64/kernel/entry-common.c:137 __el1_irq arch/arm64/kernel/entry-common.c:497 [inline] el1_interrupt+0x3c/0x60 arch/arm64/kernel/entry-common.c:510 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:515 el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:592 __daif_local_irq_restore arch/arm64/include/asm/irqflags.h:175 [inline] arch_local_irq_restore+0x8/0xc arch/arm64/include/asm/irqflags.h:195 lock_is_held include/linux/lockdep.h:249 [inline] rcu_read_lock_held+0x34/0x50 kernel/rcu/update.c:351 __find_rr_leaf+0x2d4/0x5c8 net/ipv6/route.c:833 find_rr_leaf net/ipv6/route.c:889 [inline] rt6_select net/ipv6/route.c:933 [inline] fib6_table_lookup+0x308/0x8b8 net/ipv6/route.c:2233 ip6_pol_route+0x1f8/0x101c net/ipv6/route.c:2269 ip6_pol_route_input+0x74/0x94 net/ipv6/route.c:2326 pol_lookup_func include/net/ip6_fib.h:617 [inline] fib6_rule_lookup+0x174/0x45c net/ipv6/fib6_rules.c:120 ip6_route_input_lookup net/ipv6/route.c:2338 [inline] ip6_route_input+0x5d0/0x930 net/ipv6/route.c:2641 ip6_rcv_finish_core+0x218/0x3c8 net/ipv6/ip6_input.c:66 ip6_rcv_finish+0x120/0x21c net/ipv6/ip6_input.c:77 NF_HOOK+0x2c4/0x358 include/linux/netfilter.h:318 ipv6_rcv+0x9c/0xbc net/ipv6/ip6_input.c:311 __netif_receive_skb_one_core net/core/dev.c:6137 [inline] __netif_receive_skb+0xcc/0x2a8 net/core/dev.c:6250 process_backlog+0x608/0x10e8 net/core/dev.c:6602 __napi_poll+0xb0/0x310 net/core/dev.c:7666 napi_poll net/core/dev.c:7729 [inline] net_rx_action+0x548/0xcf0 net/core/dev.c:7881 handle_softirqs+0x31c/0xc88 kernel/softirq.c:622 __do_softirq+0x14/0x20 kernel/softirq.c:656 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:68 call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:891 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:73 do_softirq+0x90/0xf8 kernel/softirq.c:523 __local_bh_enable_ip+0x240/0x35c kernel/softirq.c:450 local_bh_enable+0x28/0x34 include/linux/bottom_half.h:33 rcu_read_unlock_bh include/linux/rcupdate.h:936 [inline] __dev_queue_xmit+0x1464/0x2a68 net/core/dev.c:4844 dev_queue_xmit include/linux/netdevice.h:3381 [inline] neigh_hh_output include/net/neighbour.h:540 [inline] neigh_output include/net/neighbour.h:554 [inline] ip6_finish_output2+0x1150/0x1a78 net/ipv6/ip6_output.c:136 __ip6_finish_output net/ipv6/ip6_output.c:-1 [inline] ip6_finish_output+0x418/0x7b4 net/ipv6/ip6_output.c:220 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip6_output+0x2c8/0x640 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:464 [inline] NF_HOOK+0x15c/0x430 include/linux/netfilter.h:318 mld_sendpack+0x7fc/0x100c net/ipv6/mcast.c:1855 mld_send_initial_cr+0x34c/0x534 net/ipv6/mcast.c:2271 ipv6_mc_dad_complete+0x74/0x3a8 net/ipv6/mcast.c:2279 addrconf_dad_completed+0x604/0xb74 net/ipv6/addrconf.c:4340 addrconf_dad_work+0x928/0x10cc net/ipv6/addrconf.c:-1 process_one_work+0x7c0/0x1558 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x958/0xed8 kernel/workqueue.c:3421 kthread+0x5fc/0x75c kernel/kthread.c:463 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844 INITIAL USE at: lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0x58/0x70 kernel/locking/spinlock.c:170 spin_lock_irq include/linux/spinlock.h:376 [inline] shmem_add_to_page_cache+0x564/0xa24 mm/shmem.c:904 shmem_alloc_and_add_folio+0x758/0x10c4 mm/shmem.c:1958 shmem_get_folio_gfp+0x4d4/0x159c mm/shmem.c:2556 shmem_read_folio_gfp+0x8c/0xf0 mm/shmem.c:5974 drm_gem_get_pages+0x1cc/0x7c0 drivers/gpu/drm/drm_gem.c:654 drm_gem_shmem_get_pages_locked+0x1d4/0x364 drivers/gpu/drm/drm_gem_shmem_helper.c:239 drm_gem_shmem_pin_locked+0x1f8/0x410 drivers/gpu/drm/drm_gem_shmem_helper.c:300 drm_gem_shmem_vmap_locked+0x3cc/0x658 drivers/gpu/drm/drm_gem_shmem_helper.c:404 drm_gem_shmem_object_vmap+0x28/0x38 include/drm/drm_gem_shmem_helper.h:245 drm_gem_vmap_locked drivers/gpu/drm/drm_gem.c:1269 [inline] drm_gem_vmap+0x104/0x1d8 drivers/gpu/drm/drm_gem.c:1311 drm_client_buffer_vmap+0x68/0xb0 drivers/gpu/drm/drm_client.c:355 drm_fbdev_shmem_driver_fbdev_probe+0x1f4/0x700 drivers/gpu/drm/drm_fbdev_shmem.c:159 drm_fb_helper_single_fb_probe drivers/gpu/drm/drm_fb_helper.c:1562 [inline] __drm_fb_helper_initial_config_and_unlock+0x108c/0x1728 drivers/gpu/drm/drm_fb_helper.c:1741 drm_fb_helper_initial_config+0x3c/0x58 drivers/gpu/drm/drm_fb_helper.c:1828 drm_fbdev_client_hotplug+0x154/0x22c drivers/gpu/drm/clients/drm_fbdev_client.c:66 drm_client_register+0x13c/0x1d4 drivers/gpu/drm/drm_client.c:143 drm_fbdev_client_setup+0x194/0x3d0 drivers/gpu/drm/clients/drm_fbdev_client.c:168 drm_client_setup+0x114/0x228 drivers/gpu/drm/clients/drm_client_setup.c:46 vkms_create+0x370/0x420 drivers/gpu/drm/vkms/vkms_drv.c:211 vkms_init+0x64/0x9c drivers/gpu/drm/vkms/vkms_drv.c:239 do_one_initcall+0x248/0x9b4 init/main.c:1378 do_initcall_level+0x128/0x1c4 init/main.c:1440 do_initcalls+0x70/0xd0 init/main.c:1456 do_basic_setup+0x78/0x8c init/main.c:1475 kernel_init_freeable+0x268/0x39c init/main.c:1688 kernel_init+0x24/0x1dc init/main.c:1578 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844 } ... key at: [] xa_init_flags.__key+0x0/0x20 the dependencies between the lock to be acquired and HARDIRQ-irq-unsafe lock: -> (&p->sequence){+.-.}-{0:0} { HARDIRQ-ON-W at: lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868 do_write_seqcount_begin_nested include/linux/seqlock.h:477 [inline] do_write_seqcount_begin include/linux/seqlock.h:503 [inline] fprop_new_period+0x3b8/0x718 lib/flex_proportions.c:74 writeout_period+0x94/0x11c mm/page-writeback.c:615 call_timer_fn+0x19c/0x814 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers kernel/time/timer.c:2373 [inline] __run_timer_base+0x51c/0x76c kernel/time/timer.c:2385 run_timer_base kernel/time/timer.c:2394 [inline] run_timer_softirq+0x11c/0x194 kernel/time/timer.c:2405 handle_softirqs+0x31c/0xc88 kernel/softirq.c:622 __do_softirq+0x14/0x20 kernel/softirq.c:656 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:68 call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:891 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:73 invoke_softirq kernel/softirq.c:503 [inline] __irq_exit_rcu+0x1b0/0x478 kernel/softirq.c:723 irq_exit_rcu+0x14/0x84 kernel/softirq.c:739 __el1_irq arch/arm64/kernel/entry-common.c:498 [inline] el1_interrupt+0x40/0x60 arch/arm64/kernel/entry-common.c:510 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:515 el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:592 __daif_local_irq_restore arch/arm64/include/asm/irqflags.h:175 [inline] arch_local_irq_restore arch/arm64/include/asm/irqflags.h:195 [inline] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock_irqrestore+0x44/0x98 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] unlock_task_sighand include/linux/sched/signal.h:756 [inline] do_send_sig_info kernel/signal.c:1270 [inline] do_send_specific+0x1cc/0x2cc kernel/signal.c:4131 do_tkill kernel/signal.c:4152 [inline] __do_sys_tgkill kernel/signal.c:4171 [inline] __se_sys_tgkill kernel/signal.c:4165 [inline] __arm64_sys_tgkill+0x12c/0x188 kernel/signal.c:4165 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 IN-SOFTIRQ-W at: lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868 do_write_seqcount_begin_nested include/linux/seqlock.h:477 [inline] do_write_seqcount_begin include/linux/seqlock.h:503 [inline] fprop_new_period+0x3b8/0x718 lib/flex_proportions.c:74 writeout_period+0x94/0x11c mm/page-writeback.c:615 call_timer_fn+0x19c/0x814 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers kernel/time/timer.c:2373 [inline] __run_timer_base+0x51c/0x76c kernel/time/timer.c:2385 run_timer_base kernel/time/timer.c:2394 [inline] run_timer_softirq+0x11c/0x194 kernel/time/timer.c:2405 handle_softirqs+0x31c/0xc88 kernel/softirq.c:622 __do_softirq+0x14/0x20 kernel/softirq.c:656 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:68 call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:891 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:73 invoke_softirq kernel/softirq.c:503 [inline] __irq_exit_rcu+0x1b0/0x478 kernel/softirq.c:723 irq_exit_rcu+0x14/0x84 kernel/softirq.c:739 __el1_irq arch/arm64/kernel/entry-common.c:498 [inline] el1_interrupt+0x40/0x60 arch/arm64/kernel/entry-common.c:510 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:515 el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:592 __daif_local_irq_restore arch/arm64/include/asm/irqflags.h:175 [inline] arch_local_irq_restore arch/arm64/include/asm/irqflags.h:195 [inline] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock_irqrestore+0x44/0x98 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] unlock_task_sighand include/linux/sched/signal.h:756 [inline] do_send_sig_info kernel/signal.c:1270 [inline] do_send_specific+0x1cc/0x2cc kernel/signal.c:4131 do_tkill kernel/signal.c:4152 [inline] __do_sys_tgkill kernel/signal.c:4171 [inline] __se_sys_tgkill kernel/signal.c:4165 [inline] __arm64_sys_tgkill+0x12c/0x188 kernel/signal.c:4165 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 INITIAL USE at: lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868 do_write_seqcount_begin_nested include/linux/seqlock.h:477 [inline] do_write_seqcount_begin include/linux/seqlock.h:503 [inline] fprop_new_period+0x3b8/0x718 lib/flex_proportions.c:74 writeout_period+0x94/0x11c mm/page-writeback.c:615 call_timer_fn+0x19c/0x814 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers kernel/time/timer.c:2373 [inline] __run_timer_base+0x51c/0x76c kernel/time/timer.c:2385 run_timer_base kernel/time/timer.c:2394 [inline] run_timer_softirq+0x11c/0x194 kernel/time/timer.c:2405 handle_softirqs+0x31c/0xc88 kernel/softirq.c:622 __do_softirq+0x14/0x20 kernel/softirq.c:656 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:68 call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:891 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:73 invoke_softirq kernel/softirq.c:503 [inline] __irq_exit_rcu+0x1b0/0x478 kernel/softirq.c:723 irq_exit_rcu+0x14/0x84 kernel/softirq.c:739 __el1_irq arch/arm64/kernel/entry-common.c:498 [inline] el1_interrupt+0x40/0x60 arch/arm64/kernel/entry-common.c:510 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:515 el1h_64_irq+0x6c/0x70 arch/arm64/kernel/entry.S:592 __daif_local_irq_restore arch/arm64/include/asm/irqflags.h:175 [inline] arch_local_irq_restore arch/arm64/include/asm/irqflags.h:195 [inline] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock_irqrestore+0x44/0x98 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] unlock_task_sighand include/linux/sched/signal.h:756 [inline] do_send_sig_info kernel/signal.c:1270 [inline] do_send_specific+0x1cc/0x2cc kernel/signal.c:4131 do_tkill kernel/signal.c:4152 [inline] __do_sys_tgkill kernel/signal.c:4171 [inline] __se_sys_tgkill kernel/signal.c:4165 [inline] __arm64_sys_tgkill+0x12c/0x188 kernel/signal.c:4165 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 INITIAL READ USE at: lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868 seqcount_lockdep_reader_access include/linux/seqlock.h:72 [inline] fprop_fraction_percpu+0xac/0x270 lib/flex_proportions.c:155 __wb_calc_thresh+0xfc/0x3b0 mm/page-writeback.c:913 wb_bg_dirty_limits mm/page-writeback.c:2130 [inline] domain_over_bg_thresh+0xb8/0x1f0 mm/page-writeback.c:2144 wb_over_bg_thresh+0xf8/0x17c mm/page-writeback.c:2165 wb_check_background_flush fs/fs-writeback.c:2278 [inline] wb_do_writeback fs/fs-writeback.c:2376 [inline] wb_workfn+0xa30/0xdc0 fs/fs-writeback.c:2403 process_one_work+0x7c0/0x1558 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x958/0xed8 kernel/workqueue.c:3421 kthread+0x5fc/0x75c kernel/kthread.c:463 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844 } ... key at: [] fprop_global_init.__key.1+0x0/0x20 ... acquired at: seqcount_lockdep_reader_access include/linux/seqlock.h:72 [inline] fprop_fraction_percpu+0xf0/0x270 lib/flex_proportions.c:155 __fprop_add_percpu_max+0x130/0x1f4 lib/flex_proportions.c:186 wb_domain_writeout_add mm/page-writeback.c:562 [inline] __wb_writeout_add+0xbc/0x27c mm/page-writeback.c:586 __folio_end_writeback+0x380/0x6f8 mm/page-writeback.c:2997 folio_end_writeback_no_dropbehind+0xd0/0x204 mm/filemap.c:1661 folio_end_writeback+0xd8/0x248 mm/filemap.c:1687 iomap_finish_folio_write+0x1c0/0x2a4 fs/iomap/buffered-io.c:1713 fuse_writepage_finish fs/fuse/file.c:1903 [inline] fuse_send_writepage fs/fuse/file.c:1954 [inline] fuse_flush_writepages+0x578/0x788 fs/fuse/file.c:1979 fuse_writepages_send fs/fuse/file.c:2158 [inline] fuse_iomap_writeback_range+0x744/0x149c fs/fuse/file.c:2225 iomap_writeback_range fs/iomap/buffered-io.c:1724 [inline] iomap_writeback_folio+0x1064/0x1fc4 fs/iomap/buffered-io.c:1842 iomap_writepages+0x128/0x25c fs/iomap/buffered-io.c:1902 fuse_writepages+0x208/0x2bc fs/fuse/file.c:2295 do_writepages+0x270/0x468 mm/page-writeback.c:2598 __writeback_single_inode+0x144/0x16b8 fs/fs-writeback.c:1737 writeback_single_inode+0x3e4/0xc2c fs/fs-writeback.c:1858 write_inode_now+0x13c/0x1a4 fs/fs-writeback.c:2924 fuse_flush+0x20c/0x6a0 fs/fuse/file.c:472 filp_flush+0xb8/0x190 fs/open.c:1533 filp_close+0x28/0x48 fs/open.c:1546 __range_close fs/file.c:790 [inline] __do_sys_close_range fs/file.c:849 [inline] __se_sys_close_range fs/file.c:813 [inline] __arm64_sys_close_range+0x318/0x5c4 fs/file.c:813 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 stack backtrace: CPU: 1 UID: 0 PID: 6846 Comm: syz.4.21 Not tainted syzkaller #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_bad_irq_dependency kernel/locking/lockdep.c:2616 [inline] check_irq_usage kernel/locking/lockdep.c:2857 [inline] check_prev_add kernel/locking/lockdep.c:3169 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x3058/0x30a4 kernel/locking/lockdep.c:5237 lock_acquire+0x140/0x2e0 kernel/locking/lockdep.c:5868 seqcount_lockdep_reader_access include/linux/seqlock.h:72 [inline] fprop_fraction_percpu+0xf0/0x270 lib/flex_proportions.c:155 __fprop_add_percpu_max+0x130/0x1f4 lib/flex_proportions.c:186 wb_domain_writeout_add mm/page-writeback.c:562 [inline] __wb_writeout_add+0xbc/0x27c mm/page-writeback.c:586 __folio_end_writeback+0x380/0x6f8 mm/page-writeback.c:2997 folio_end_writeback_no_dropbehind+0xd0/0x204 mm/filemap.c:1661 folio_end_writeback+0xd8/0x248 mm/filemap.c:1687 iomap_finish_folio_write+0x1c0/0x2a4 fs/iomap/buffered-io.c:1713 fuse_writepage_finish fs/fuse/file.c:1903 [inline] fuse_send_writepage fs/fuse/file.c:1954 [inline] fuse_flush_writepages+0x578/0x788 fs/fuse/file.c:1979 fuse_writepages_send fs/fuse/file.c:2158 [inline] fuse_iomap_writeback_range+0x744/0x149c fs/fuse/file.c:2225 iomap_writeback_range fs/iomap/buffered-io.c:1724 [inline] iomap_writeback_folio+0x1064/0x1fc4 fs/iomap/buffered-io.c:1842 iomap_writepages+0x128/0x25c fs/iomap/buffered-io.c:1902 fuse_writepages+0x208/0x2bc fs/fuse/file.c:2295 do_writepages+0x270/0x468 mm/page-writeback.c:2598 __writeback_single_inode+0x144/0x16b8 fs/fs-writeback.c:1737 writeback_single_inode+0x3e4/0xc2c fs/fs-writeback.c:1858 write_inode_now+0x13c/0x1a4 fs/fs-writeback.c:2924 fuse_flush+0x20c/0x6a0 fs/fuse/file.c:472 filp_flush+0xb8/0x190 fs/open.c:1533 filp_close+0x28/0x48 fs/open.c:1546 __range_close fs/file.c:790 [inline] __do_sys_close_range fs/file.c:849 [inline] __se_sys_close_range fs/file.c:813 [inline] __arm64_sys_close_range+0x318/0x5c4 fs/file.c:813 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x5c/0x26c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596