====================================================== WARNING: possible circular locking dependency detected 6.13.0-rc6-syzkaller-00036-gfbfd64d25c7a #0 Not tainted ------------------------------------------------------ kswapd0/71 is trying to acquire lock: ffff800086e2f730 (cpu_hotplug_lock){++++}-{0:0}, at: cpus_read_lock+0x10/0x1c kernel/cpu.c:490 but task is already holding lock: ffff8000870fe700 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x610/0x1110 mm/vmscan.c:6992 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (fs_reclaim){+.+.}-{0:0}: __fs_reclaim_acquire mm/page_alloc.c:3853 [inline] fs_reclaim_acquire+0x138/0x160 mm/page_alloc.c:3867 might_alloc include/linux/sched/mm.h:318 [inline] slab_pre_alloc_hook mm/slub.c:4070 [inline] slab_alloc_node mm/slub.c:4148 [inline] __kmalloc_cache_node_noprof+0x64/0x3cc mm/slub.c:4337 kmalloc_node_noprof include/linux/slab.h:924 [inline] alloc_worker kernel/workqueue.c:2638 [inline] create_worker+0xf8/0x694 kernel/workqueue.c:2781 workqueue_prepare_cpu+0xb4/0x164 kernel/workqueue.c:6628 cpuhp_invoke_callback+0x304/0x6f8 kernel/cpu.c:194 __cpuhp_invoke_callback_range+0x15c/0x248 kernel/cpu.c:965 cpuhp_invoke_callback_range kernel/cpu.c:989 [inline] cpuhp_up_callbacks kernel/cpu.c:1020 [inline] _cpu_up+0x194/0x2f4 kernel/cpu.c:1690 cpu_up+0x120/0x19c kernel/cpu.c:1722 cpuhp_bringup_mask kernel/cpu.c:1788 [inline] bringup_nonboot_cpus+0x88/0x118 kernel/cpu.c:1896 smp_init+0x3c/0xf0 kernel/smp.c:1009 kernel_init_freeable+0x2e4/0x6c0 init/main.c:1569 kernel_init+0x24/0x1e0 init/main.c:1466 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862 -> #0 (cpu_hotplug_lock){++++}-{0:0}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x2b80/0x6604 kernel/locking/lockdep.c:5226 lock_acquire kernel/locking/lockdep.c:5849 [inline] lock_acquire+0x450/0x76c kernel/locking/lockdep.c:5814 percpu_down_read.constprop.0+0x58/0x1f4 include/linux/percpu-rwsem.h:51 cpus_read_lock+0x10/0x1c kernel/cpu.c:490 acomp_ctx_get_cpu mm/zswap.c:886 [inline] zswap_compress mm/zswap.c:908 [inline] zswap_store_page mm/zswap.c:1439 [inline] zswap_store+0x4f0/0x14b0 mm/zswap.c:1546 swap_writepage+0x4b0/0xcd4 mm/page_io.c:279 shmem_writepage+0x9a8/0xd98 mm/shmem.c:1579 pageout+0x2d0/0x9b0 mm/vmscan.c:696 shrink_folio_list+0x203c/0x2fe8 mm/vmscan.c:1374 evict_folios+0x520/0x1410 mm/vmscan.c:4600 try_to_shrink_lruvec+0x368/0x6a0 mm/vmscan.c:4796 shrink_one+0x114/0x4cc mm/vmscan.c:4841 shrink_many mm/vmscan.c:4904 [inline] lru_gen_shrink_node mm/vmscan.c:4982 [inline] shrink_node+0x18dc/0x26c0 mm/vmscan.c:5963 kswapd_shrink_node mm/vmscan.c:6792 [inline] balance_pgdat+0x5ac/0x1110 mm/vmscan.c:6984 kswapd+0x554/0xe74 mm/vmscan.c:7253 kthread+0x27c/0x300 kernel/kthread.c:389 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(cpu_hotplug_lock); lock(fs_reclaim); rlock(cpu_hotplug_lock); *** DEADLOCK *** 1 lock held by kswapd0/71: #0: ffff8000870fe700 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x610/0x1110 mm/vmscan.c:6992 stack backtrace: CPU: 1 UID: 0 PID: 71 Comm: kswapd0 Not tainted 6.13.0-rc6-syzkaller-00036-gfbfd64d25c7a #0 Hardware name: linux,dummy-virt (DT) Call trace: show_stack+0x18/0x24 arch/arm64/kernel/stacktrace.c:466 (C) __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xa4/0xf4 lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x428/0x704 kernel/locking/lockdep.c:2074 check_noncircular+0x2dc/0x364 kernel/locking/lockdep.c:2206 check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x2b80/0x6604 kernel/locking/lockdep.c:5226 lock_acquire kernel/locking/lockdep.c:5849 [inline] lock_acquire+0x450/0x76c kernel/locking/lockdep.c:5814 percpu_down_read.constprop.0+0x58/0x1f4 include/linux/percpu-rwsem.h:51 cpus_read_lock+0x10/0x1c kernel/cpu.c:490 acomp_ctx_get_cpu mm/zswap.c:886 [inline] zswap_compress mm/zswap.c:908 [inline] zswap_store_page mm/zswap.c:1439 [inline] zswap_store+0x4f0/0x14b0 mm/zswap.c:1546 swap_writepage+0x4b0/0xcd4 mm/page_io.c:279 shmem_writepage+0x9a8/0xd98 mm/shmem.c:1579 pageout+0x2d0/0x9b0 mm/vmscan.c:696 shrink_folio_list+0x203c/0x2fe8 mm/vmscan.c:1374 evict_folios+0x520/0x1410 mm/vmscan.c:4600 try_to_shrink_lruvec+0x368/0x6a0 mm/vmscan.c:4796 shrink_one+0x114/0x4cc mm/vmscan.c:4841 shrink_many mm/vmscan.c:4904 [inline] lru_gen_shrink_node mm/vmscan.c:4982 [inline] shrink_node+0x18dc/0x26c0 mm/vmscan.c:5963 kswapd_shrink_node mm/vmscan.c:6792 [inline] balance_pgdat+0x5ac/0x1110 mm/vmscan.c:6984 kswapd+0x554/0xe74 mm/vmscan.c:7253 kthread+0x27c/0x300 kernel/kthread.c:389 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862