syzbot

=====================================================
WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected
syzkaller #0 Not tainted
-----------------------------------------------------
syz.4.54/6936 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
ffff8000973c1dd0 (&p->sequence){+.-.}-{0:0}, at: __fprop_add_percpu_max+0x130/0x1f4 lib/flex_proportions.c:186

and this task is already holding:
ffff0000c17e8240 (&xa->xa_lock#10){..-.}-{3:3}, at: __folio_end_writeback+0x10c/0x75c mm/page-writeback.c:2996
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:
 (&fq->mq_flush_lock){-.-.}-{3:3}

... which became HARDIRQ-irq-safe at:
  lock_acquire+0x14c/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
  flush_end_io+0xb4/0xd68 block/blk-flush.c:211
  __blk_mq_end_request+0x37c/0x57c block/blk-mq.c:1150
  blk_mq_end_request+0x68/0x88 block/blk-mq.c:1162
  nvme_end_req drivers/nvme/host/core.c:454 [inline]
  nvme_complete_rq+0x150/0x464 drivers/nvme/host/core.c:-1
  nvme_pci_complete_rq drivers/nvme/host/pci.c:1272 [inline]
  nvme_handle_cqe drivers/nvme/host/pci.c:1336 [inline]
  nvme_poll_cq+0x65c/0x1018 drivers/nvme/host/pci.c:1363
  nvme_irq+0x90/0x240 drivers/nvme/host/pci.c:1377
  __handle_irq_event_percpu+0x224/0x8e4 kernel/irq/handle.c:203
  handle_irq_event_percpu kernel/irq/handle.c:240 [inline]
  handle_irq_event+0x9c/0x1d0 kernel/irq/handle.c:257
  handle_fasteoi_irq+0x328/0x8d8 kernel/irq/chip.c:764
  generic_handle_irq_desc include/linux/irqdesc.h:173 [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:874 [inline]
  __gic_handle_irq_from_irqson drivers/irqchip/irq-gic-v3.c:925 [inline]
  gic_handle_irq+0x6c/0x190 drivers/irqchip/irq-gic-v3.c:969
  call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:891
  do_interrupt_handler+0xd4/0x138 arch/arm64/kernel/entry-common.c:135
  __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_enable arch/arm64/include/asm/irqflags.h:26 [inline]
  arch_local_irq_enable arch/arm64/include/asm/irqflags.h:48 [inline]
  raw_spin_rq_unlock_irq kernel/sched/sched.h:1559 [inline]
  finish_lock_switch+0xb4/0x1c0 kernel/sched/core.c:5073
  finish_task_switch+0x120/0x5a4 kernel/sched/core.c:5191
  context_switch kernel/sched/core.c:5328 [inline]
  __schedule+0x13b4/0x2864 kernel/sched/core.c:6929
  __schedule_loop kernel/sched/core.c:7011 [inline]
  schedule+0xb4/0x230 kernel/sched/core.c:7026
  exit_to_user_mode_loop+0x6c/0x178 kernel/entry/common.c:31
  exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
  arm64_exit_to_user_mode arch/arm64/kernel/entry-common.c:81 [inline]
  el0_interrupt+0x180/0x2a4 arch/arm64/kernel/entry-common.c:819
  __el0_irq_handler_common+0x18/0x24 arch/arm64/kernel/entry-common.c:824
  el0t_64_irq_handler+0x10/0x1c arch/arm64/kernel/entry-common.c:829
  el0t_64_irq+0x198/0x19c arch/arm64/kernel/entry.S:597

to a HARDIRQ-irq-unsafe lock:
 (&p->sequence){+.-.}-{0:0}

... which became HARDIRQ-irq-unsafe at:
...
  lock_acquire+0x14c/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+0x1b4/0x818 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+0x328/0xc88 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]
  lock_release+0x270/0x39c kernel/locking/lockdep.c:5892
  rcu_lock_release+0x2c/0x38 include/linux/rcupdate.h:341
  rcu_read_unlock include/linux/rcupdate.h:897 [inline]
  __d_lookup+0x5d0/0x674 fs/dcache.c:2413
  lookup_fast+0x7c/0x4b0 fs/namei.c:1774
  walk_component fs/namei.c:2147 [inline]
  link_path_walk+0x568/0xc98 fs/namei.c:2519
  path_lookupat+0x90/0x3d0 fs/namei.c:2675
  filename_lookup+0x1ac/0x454 fs/namei.c:2705
  do_readlinkat+0xd4/0x474 fs/stat.c:576
  __do_sys_readlinkat fs/stat.c:607 [inline]
  __se_sys_readlinkat fs/stat.c:604 [inline]
  __arm64_sys_readlinkat+0x9c/0xb8 fs/stat.c:604
  __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/0x254 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:

Chain exists of:
  &fq->mq_flush_lock --> &xa->xa_lock#10 --> &p->sequence

 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&p->sequence);
                               local_irq_disable();
                               lock(&fq->mq_flush_lock);
                               lock(&xa->xa_lock#10);
  <Interrupt>
    lock(&fq->mq_flush_lock);

 *** DEADLOCK ***

2 locks held by syz.4.54/6936:
 #0: ffff0000c17e8638 (&fi->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #0: ffff0000c17e8638 (&fi->lock){+.+.}-{3:3}, at: fuse_writepages_send fs/fuse/file.c:2089 [inline]
 #0: ffff0000c17e8638 (&fi->lock){+.+.}-{3:3}, at: fuse_iomap_writeback_range+0x3b8/0x152c fs/fuse/file.c:2150
 #1: ffff0000c17e8240 (&xa->xa_lock#10){..-.}-{3:3}, at: __folio_end_writeback+0x10c/0x75c mm/page-writeback.c:2996

the dependencies between HARDIRQ-irq-safe lock and the holding lock:
 -> (&fq->mq_flush_lock){-.-.}-{3:3} {
    IN-HARDIRQ-W at:
                      lock_acquire+0x14c/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
                      flush_end_io+0xb4/0xd68 block/blk-flush.c:211
                      __blk_mq_end_request+0x37c/0x57c block/blk-mq.c:1150
                      blk_mq_end_request+0x68/0x88 block/blk-mq.c:1162
                      nvme_end_req drivers/nvme/host/core.c:454 [inline]
                      nvme_complete_rq+0x150/0x464 drivers/nvme/host/core.c:-1
                      nvme_pci_complete_rq drivers/nvme/host/pci.c:1272 [inline]
                      nvme_handle_cqe drivers/nvme/host/pci.c:1336 [inline]
                      nvme_poll_cq+0x65c/0x1018 drivers/nvme/host/pci.c:1363
                      nvme_irq+0x90/0x240 drivers/nvme/host/pci.c:1377
                      __handle_irq_event_percpu+0x224/0x8e4 kernel/irq/handle.c:203
                      handle_irq_event_percpu kernel/irq/handle.c:240 [inline]
                      handle_irq_event+0x9c/0x1d0 kernel/irq/handle.c:257
                      handle_fasteoi_irq+0x328/0x8d8 kernel/irq/chip.c:764
                      generic_handle_irq_desc include/linux/irqdesc.h:173 [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:874 [inline]
                      __gic_handle_irq_from_irqson drivers/irqchip/irq-gic-v3.c:925 [inline]
                      gic_handle_irq+0x6c/0x190 drivers/irqchip/irq-gic-v3.c:969
                      call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:891
                      do_interrupt_handler+0xd4/0x138 arch/arm64/kernel/entry-common.c:135
                      __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_enable arch/arm64/include/asm/irqflags.h:26 [inline]
                      arch_local_irq_enable arch/arm64/include/asm/irqflags.h:48 [inline]
                      raw_spin_rq_unlock_irq kernel/sched/sched.h:1559 [inline]
                      finish_lock_switch+0xb4/0x1c0 kernel/sched/core.c:5073
                      finish_task_switch+0x120/0x5a4 kernel/sched/core.c:5191
                      context_switch kernel/sched/core.c:5328 [inline]
                      __schedule+0x13b4/0x2864 kernel/sched/core.c:6929
                      __schedule_loop kernel/sched/core.c:7011 [inline]
                      schedule+0xb4/0x230 kernel/sched/core.c:7026
                      exit_to_user_mode_loop+0x6c/0x178 kernel/entry/common.c:31
                      exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
                      arm64_exit_to_user_mode arch/arm64/kernel/entry-common.c:81 [inline]
                      el0_interrupt+0x180/0x2a4 arch/arm64/kernel/entry-common.c:819
                      __el0_irq_handler_common+0x18/0x24 arch/arm64/kernel/entry-common.c:824
                      el0t_64_irq_handler+0x10/0x1c arch/arm64/kernel/entry-common.c:829
                      el0t_64_irq+0x198/0x19c arch/arm64/kernel/entry.S:597
    IN-SOFTIRQ-W at:
                      lock_acquire+0x14c/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
                      mq_flush_data_end_io+0x270/0x480 block/blk-flush.c:355
                      __blk_mq_end_request+0x37c/0x57c block/blk-mq.c:1150
                      blk_mq_end_request+0x68/0x88 block/blk-mq.c:1162
                      lo_complete_rq+0x124/0x274 drivers/block/loop.c:314
                      blk_complete_reqs block/blk-mq.c:1235 [inline]
                      blk_done_softirq+0x11c/0x168 block/blk-mq.c:1240
                      handle_softirqs+0x328/0xc88 kernel/softirq.c:622
                      run_ksoftirqd+0x70/0xc0 kernel/softirq.c:1063
                      smpboot_thread_fn+0x4d8/0x9cc kernel/smpboot.c:160
                      kthread+0x5fc/0x75c kernel/kthread.c:463
                      ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844
    INITIAL USE at:
                     lock_acquire+0x14c/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]
                     blk_insert_flush+0x360/0x4b8 block/blk-flush.c:454
                     blk_mq_submit_bio+0x1614/0x2168 block/blk-mq.c:3218
                     __submit_bio+0x1d8/0x4d8 block/blk-core.c:637
                     __submit_bio_noacct_mq block/blk-core.c:724 [inline]
                     submit_bio_noacct_nocheck+0x29c/0x9a4 block/blk-core.c:755
                     submit_bio_noacct+0xde0/0x186c block/blk-core.c:879
                     submit_bio+0x3b4/0x550 block/blk-core.c:921
                     submit_bio_wait+0x104/0x208 block/bio.c:1388
                     blkdev_issue_flush+0xb4/0x100 block/blk-flush.c:473
                     ext4_init_inode_table+0x420/0x780 fs/ext4/ialloc.c:1603
                     ext4_run_li_request fs/ext4/super.c:3729 [inline]
                     ext4_lazyinit_thread+0x704/0x1744 fs/ext4/super.c:3824
                     kthread+0x5fc/0x75c kernel/kthread.c:463
                     ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844
  }
  ... key      at: [<ffff8000975641a0>] blk_alloc_flush_queue.__key+0x0/0x20
-> (&xa->xa_lock#10){..-.}-{3:3} {
   IN-SOFTIRQ-W at:
                    lock_acquire+0x14c/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/0x75c mm/page-writeback.c:2996
                    folio_end_writeback_no_dropbehind+0xd0/0x204 mm/filemap.c:1668
                    folio_end_writeback+0xd8/0x248 mm/filemap.c:1694
                    btrfs_meta_folio_clear_writeback+0xcc/0x11c fs/btrfs/subpage.c:666
                    end_bbio_meta_write+0x284/0x440 fs/btrfs/extent_io.c:2163
                    btrfs_bio_end_io+0x2a4/0x41c fs/btrfs/bio.c:133
                    btrfs_simple_end_io+0x390/0x4a0 fs/btrfs/bio.c:348
                    bio_endio+0x858/0x894 block/bio.c:1672
                    blk_update_request+0x474/0xba8 block/blk-mq.c:998
                    blk_mq_end_request+0x54/0x88 block/blk-mq.c:1160
                    lo_complete_rq+0x124/0x274 drivers/block/loop.c:314
                    blk_complete_reqs block/blk-mq.c:1235 [inline]
                    blk_done_softirq+0x11c/0x168 block/blk-mq.c:1240
                    handle_softirqs+0x328/0xc88 kernel/softirq.c:622
                    run_ksoftirqd+0x70/0xc0 kernel/softirq.c:1063
                    smpboot_thread_fn+0x4d8/0x9cc kernel/smpboot.c:160
                    kthread+0x5fc/0x75c kernel/kthread.c:463
                    ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844
   INITIAL USE at:
                   lock_acquire+0x14c/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:886
                   shmem_alloc_and_add_folio+0x758/0x10c4 mm/shmem.c:1938
                   shmem_get_folio_gfp+0x4d4/0x159c mm/shmem.c:2535
                   shmem_read_folio_gfp+0x8c/0xf0 mm/shmem.c:5933
                   drm_gem_get_pages+0x1cc/0x7c0 drivers/gpu/drm/drm_gem.c:656
                   drm_gem_shmem_get_pages_locked+0x1d4/0x364 drivers/gpu/drm/drm_gem_shmem_helper.c:200
                   drm_gem_shmem_pin_locked+0x1f8/0x410 drivers/gpu/drm/drm_gem_shmem_helper.c:261
                   drm_gem_shmem_vmap_locked+0x3cc/0x658 drivers/gpu/drm/drm_gem_shmem_helper.c:365
                   drm_gem_shmem_object_vmap+0x28/0x38 include/drm/drm_gem_shmem_helper.h:243
                   drm_gem_vmap_locked drivers/gpu/drm/drm_gem.c:1279 [inline]
                   drm_gem_vmap+0x104/0x1d8 drivers/gpu/drm/drm_gem.c:1321
                   drm_client_buffer_vmap+0x48/0x90 drivers/gpu/drm/drm_client.c:312
                   drm_fbdev_shmem_driver_fbdev_probe+0x1d8/0x70c drivers/gpu/drm/drm_fbdev_shmem.c:160
                   drm_fb_helper_single_fb_probe drivers/gpu/drm/drm_fb_helper.c:1650 [inline]
                   __drm_fb_helper_initial_config_and_unlock+0xf94/0x159c drivers/gpu/drm/drm_fb_helper.c:1830
                   drm_fb_helper_initial_config+0x3c/0x58 drivers/gpu/drm/drm_fb_helper.c:1917
                   drm_fbdev_client_hotplug+0x154/0x22c drivers/gpu/drm/clients/drm_fbdev_client.c:52
                   drm_client_register+0x13c/0x1d4 drivers/gpu/drm/drm_client.c:141
                   drm_fbdev_client_setup+0x194/0x3d0 drivers/gpu/drm/clients/drm_fbdev_client.c:159
                   drm_client_setup+0x114/0x228 drivers/gpu/drm/clients/drm_client_setup.c:46
                   vkms_create drivers/gpu/drm/vkms/vkms_drv.c:201 [inline]
                   vkms_init+0x338/0x3f0 drivers/gpu/drm/vkms/vkms_drv.c:221
                   do_one_initcall+0x250/0x990 init/main.c:1283
                   do_initcall_level+0x128/0x1c4 init/main.c:1345
                   do_initcalls+0x70/0xd0 init/main.c:1361
                   do_basic_setup+0x78/0x8c init/main.c:1380
                   kernel_init_freeable+0x268/0x39c init/main.c:1593
                   kernel_init+0x24/0x1dc init/main.c:1483
                   ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844
 }
 ... key      at: [<ffff8000973e6280>] xa_init_flags.__key+0x0/0x20
 ... acquired at:
   __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/0x75c mm/page-writeback.c:2996
   folio_end_writeback_no_dropbehind+0xd0/0x204 mm/filemap.c:1668
   folio_end_writeback+0xd8/0x248 mm/filemap.c:1694
   f2fs_write_end_io+0x6b8/0xa70 fs/f2fs/data.c:362
   bio_endio+0x858/0x894 block/bio.c:1672
   blk_update_request+0x474/0xba8 block/blk-mq.c:998
   blk_mq_end_request+0x54/0x88 block/blk-mq.c:1160
   blk_flush_complete_seq+0x57c/0xad4 block/blk-flush.c:191
   flush_end_io+0x9e8/0xd68 block/blk-flush.c:250
   __blk_mq_end_request+0x37c/0x57c block/blk-mq.c:1150
   blk_mq_end_request+0x68/0x88 block/blk-mq.c:1162
   lo_complete_rq+0x124/0x274 drivers/block/loop.c:314
   blk_complete_reqs block/blk-mq.c:1235 [inline]
   blk_done_softirq+0x11c/0x168 block/blk-mq.c:1240
   handle_softirqs+0x328/0xc88 kernel/softirq.c:622
   run_ksoftirqd+0x70/0xc0 kernel/softirq.c:1063
   smpboot_thread_fn+0x4d8/0x9cc kernel/smpboot.c:160
   kthread+0x5fc/0x75c kernel/kthread.c:463
   ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844


the dependencies between the lock to be acquired
 and HARDIRQ-irq-unsafe lock:
-> (&p->sequence){+.-.}-{0:0} {
   HARDIRQ-ON-W at:
                    lock_acquire+0x14c/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+0x1b4/0x818 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+0x328/0xc88 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]
                    lock_release+0x270/0x39c kernel/locking/lockdep.c:5892
                    rcu_lock_release+0x2c/0x38 include/linux/rcupdate.h:341
                    rcu_read_unlock include/linux/rcupdate.h:897 [inline]
                    __d_lookup+0x5d0/0x674 fs/dcache.c:2413
                    lookup_fast+0x7c/0x4b0 fs/namei.c:1774
                    walk_component fs/namei.c:2147 [inline]
                    link_path_walk+0x568/0xc98 fs/namei.c:2519
                    path_lookupat+0x90/0x3d0 fs/namei.c:2675
                    filename_lookup+0x1ac/0x454 fs/namei.c:2705
                    do_readlinkat+0xd4/0x474 fs/stat.c:576
                    __do_sys_readlinkat fs/stat.c:607 [inline]
                    __se_sys_readlinkat fs/stat.c:604 [inline]
                    __arm64_sys_readlinkat+0x9c/0xb8 fs/stat.c:604
                    __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/0x254 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+0x14c/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+0x1b4/0x818 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+0x328/0xc88 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]
                    lock_release+0x270/0x39c kernel/locking/lockdep.c:5892
                    rcu_lock_release+0x2c/0x38 include/linux/rcupdate.h:341
                    rcu_read_unlock include/linux/rcupdate.h:897 [inline]
                    __d_lookup+0x5d0/0x674 fs/dcache.c:2413
                    lookup_fast+0x7c/0x4b0 fs/namei.c:1774
                    walk_component fs/namei.c:2147 [inline]
                    link_path_walk+0x568/0xc98 fs/namei.c:2519
                    path_lookupat+0x90/0x3d0 fs/namei.c:2675
                    filename_lookup+0x1ac/0x454 fs/namei.c:2705
                    do_readlinkat+0xd4/0x474 fs/stat.c:576
                    __do_sys_readlinkat fs/stat.c:607 [inline]
                    __se_sys_readlinkat fs/stat.c:604 [inline]
                    __arm64_sys_readlinkat+0x9c/0xb8 fs/stat.c:604
                    __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/0x254 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+0x14c/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+0x1b4/0x818 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+0x328/0xc88 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]
                   lock_release+0x270/0x39c kernel/locking/lockdep.c:5892
                   rcu_lock_release+0x2c/0x38 include/linux/rcupdate.h:341
                   rcu_read_unlock include/linux/rcupdate.h:897 [inline]
                   __d_lookup+0x5d0/0x674 fs/dcache.c:2413
                   lookup_fast+0x7c/0x4b0 fs/namei.c:1774
                   walk_component fs/namei.c:2147 [inline]
                   link_path_walk+0x568/0xc98 fs/namei.c:2519
                   path_lookupat+0x90/0x3d0 fs/namei.c:2675
                   filename_lookup+0x1ac/0x454 fs/namei.c:2705
                   do_readlinkat+0xd4/0x474 fs/stat.c:576
                   __do_sys_readlinkat fs/stat.c:607 [inline]
                   __se_sys_readlinkat fs/stat.c:604 [inline]
                   __arm64_sys_readlinkat+0x9c/0xb8 fs/stat.c:604
                   __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/0x254 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+0x14c/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:2257 [inline]
                        wb_do_writeback fs/fs-writeback.c:2355 [inline]
                        wb_workfn+0xa30/0xdc0 fs/fs-writeback.c:2382
                        process_one_work+0x7e8/0x155c kernel/workqueue.c:3263
                        process_scheduled_works kernel/workqueue.c:3346 [inline]
                        worker_thread+0x958/0xed8 kernel/workqueue.c:3427
                        kthread+0x5fc/0x75c kernel/kthread.c:463
                        ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844
 }
 ... key      at: [<ffff800097934bc0>] 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+0x380/0x75c mm/page-writeback.c:3003
   folio_end_writeback_no_dropbehind+0xd0/0x204 mm/filemap.c:1668
   folio_end_writeback+0xd8/0x248 mm/filemap.c:1694
   iomap_finish_folio_write+0x1c0/0x2a4 fs/iomap/buffered-io.c:1582
   fuse_writepage_finish fs/fuse/file.c:1837 [inline]
   fuse_send_writepage fs/fuse/file.c:1887 [inline]
   fuse_flush_writepages+0x54c/0x73c fs/fuse/file.c:1912
   fuse_writepages_send fs/fuse/file.c:2091 [inline]
   fuse_iomap_writeback_range+0x48c/0x152c fs/fuse/file.c:2150
   iomap_writeback_range fs/iomap/buffered-io.c:1593 [inline]
   iomap_writeback_folio+0xee4/0x1c74 fs/iomap/buffered-io.c:1718
   iomap_writepages+0x128/0x25c fs/iomap/buffered-io.c:1770
   fuse_writepages+0x208/0x2bc fs/fuse/file.c:2220
   do_writepages+0x270/0x468 mm/page-writeback.c:2604
   __writeback_single_inode+0x15c/0x13e8 fs/fs-writeback.c:1719
   writeback_single_inode+0x18c/0x54c fs/fs-writeback.c:1840
   write_inode_now+0x13c/0x1a4 fs/fs-writeback.c:2903
   fuse_flush+0x20c/0x6a0 fs/fuse/file.c:460
   filp_flush+0xb8/0x190 fs/open.c:1549
   filp_close+0x28/0x48 fs/open.c:1562
   __range_close fs/file.c:767 [inline]
   __do_sys_close_range fs/file.c:826 [inline]
   __se_sys_close_range fs/file.c:790 [inline]
   __arm64_sys_close_range+0x318/0x5c4 fs/file.c:790
   __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/0x254 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: 6936 Comm: syz.4.54 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+0x14c/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+0x380/0x75c mm/page-writeback.c:3003
 folio_end_writeback_no_dropbehind+0xd0/0x204 mm/filemap.c:1668
 folio_end_writeback+0xd8/0x248 mm/filemap.c:1694
 iomap_finish_folio_write+0x1c0/0x2a4 fs/iomap/buffered-io.c:1582
 fuse_writepage_finish fs/fuse/file.c:1837 [inline]
 fuse_send_writepage fs/fuse/file.c:1887 [inline]
 fuse_flush_writepages+0x54c/0x73c fs/fuse/file.c:1912
 fuse_writepages_send fs/fuse/file.c:2091 [inline]
 fuse_iomap_writeback_range+0x48c/0x152c fs/fuse/file.c:2150
 iomap_writeback_range fs/iomap/buffered-io.c:1593 [inline]
 iomap_writeback_folio+0xee4/0x1c74 fs/iomap/buffered-io.c:1718
 iomap_writepages+0x128/0x25c fs/iomap/buffered-io.c:1770
 fuse_writepages+0x208/0x2bc fs/fuse/file.c:2220
 do_writepages+0x270/0x468 mm/page-writeback.c:2604
 __writeback_single_inode+0x15c/0x13e8 fs/fs-writeback.c:1719
 writeback_single_inode+0x18c/0x54c fs/fs-writeback.c:1840
 write_inode_now+0x13c/0x1a4 fs/fs-writeback.c:2903
 fuse_flush+0x20c/0x6a0 fs/fuse/file.c:460
 filp_flush+0xb8/0x190 fs/open.c:1549
 filp_close+0x28/0x48 fs/open.c:1562
 __range_close fs/file.c:767 [inline]
 __do_sys_close_range fs/file.c:826 [inline]
 __se_sys_close_range fs/file.c:790 [inline]
 __arm64_sys_close_range+0x318/0x5c4 fs/file.c:790
 __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/0x254 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