====================================================== WARNING: possible circular locking dependency detected 6.13.0-rc7-syzkaller-g5bc55a333a2f #0 Not tainted ------------------------------------------------------ kswapd0/113 is trying to acquire lock: ffffffff8e05ef50 (cpu_hotplug_lock){++++}-{0:0}, at: acomp_ctx_get_cpu mm/zswap.c:886 [inline] ffffffff8e05ef50 (cpu_hotplug_lock){++++}-{0:0}, at: zswap_compress mm/zswap.c:908 [inline] ffffffff8e05ef50 (cpu_hotplug_lock){++++}-{0:0}, at: zswap_store_page mm/zswap.c:1439 [inline] ffffffff8e05ef50 (cpu_hotplug_lock){++++}-{0:0}, at: zswap_store+0x905/0x26a0 mm/zswap.c:1546 but task is already holding lock: ffffffff8e350ae0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x16e/0x18f0 mm/vmscan.c:6871 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+0x102/0x150 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+0x54/0x420 mm/slub.c:4337 kmalloc_node_noprof include/linux/slab.h:924 [inline] alloc_worker kernel/workqueue.c:2645 [inline] create_worker+0x10a/0x800 kernel/workqueue.c:2788 workqueue_prepare_cpu+0xb5/0x160 kernel/workqueue.c:6635 cpuhp_invoke_callback+0x3d0/0xa10 kernel/cpu.c:194 __cpuhp_invoke_callback_range+0x101/0x200 kernel/cpu.c:965 cpuhp_invoke_callback_range kernel/cpu.c:989 [inline] cpuhp_up_callbacks kernel/cpu.c:1020 [inline] _cpu_up+0x3fd/0x910 kernel/cpu.c:1690 cpu_up+0x1dc/0x240 kernel/cpu.c:1722 cpuhp_bringup_mask+0xdc/0x210 kernel/cpu.c:1788 cpuhp_bringup_cpus_parallel kernel/cpu.c:1866 [inline] bringup_nonboot_cpus+0xf5/0x1c0 kernel/cpu.c:1892 smp_init+0x34/0x160 kernel/smp.c:1009 kernel_init_freeable+0x3ad/0x900 init/main.c:1569 kernel_init+0x1c/0x2b0 init/main.c:1466 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #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+0x249e/0x3c40 kernel/locking/lockdep.c:5226 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] cpus_read_lock+0x42/0x160 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+0x905/0x26a0 mm/zswap.c:1546 swap_writepage+0x3b6/0x1120 mm/page_io.c:279 pageout+0x3b2/0xaa0 mm/vmscan.c:696 shrink_folio_list+0x3025/0x42d0 mm/vmscan.c:1374 evict_folios+0x6e3/0x19c0 mm/vmscan.c:4600 try_to_shrink_lruvec+0x61e/0xa80 mm/vmscan.c:4796 shrink_one+0x3e3/0x7b0 mm/vmscan.c:4841 shrink_many mm/vmscan.c:4904 [inline] lru_gen_shrink_node mm/vmscan.c:4982 [inline] shrink_node+0x2763/0x3e60 mm/vmscan.c:5963 kswapd_shrink_node mm/vmscan.c:6792 [inline] balance_pgdat+0xc1f/0x18f0 mm/vmscan.c:6984 kswapd+0x605/0xc00 mm/vmscan.c:7253 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 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 kswapd0/113: #0: ffffffff8e350ae0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x16e/0x18f0 mm/vmscan.c:6871 stack backtrace: CPU: 0 UID: 0 PID: 113 Comm: kswapd0 Not tainted 6.13.0-rc7-syzkaller-g5bc55a333a2f #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x419/0x5d0 kernel/locking/lockdep.c:2074 check_noncircular+0x31a/0x400 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+0x249e/0x3c40 kernel/locking/lockdep.c:5226 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] cpus_read_lock+0x42/0x160 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+0x905/0x26a0 mm/zswap.c:1546 swap_writepage+0x3b6/0x1120 mm/page_io.c:279 pageout+0x3b2/0xaa0 mm/vmscan.c:696 shrink_folio_list+0x3025/0x42d0 mm/vmscan.c:1374 evict_folios+0x6e3/0x19c0 mm/vmscan.c:4600 try_to_shrink_lruvec+0x61e/0xa80 mm/vmscan.c:4796 shrink_one+0x3e3/0x7b0 mm/vmscan.c:4841 shrink_many mm/vmscan.c:4904 [inline] lru_gen_shrink_node mm/vmscan.c:4982 [inline] shrink_node+0x2763/0x3e60 mm/vmscan.c:5963 kswapd_shrink_node mm/vmscan.c:6792 [inline] balance_pgdat+0xc1f/0x18f0 mm/vmscan.c:6984 kswapd+0x605/0xc00 mm/vmscan.c:7253 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244