====================================================== WARNING: possible circular locking dependency detected 6.13.0-rc6-syzkaller-gfbfd64d25c7a #0 Not tainted ------------------------------------------------------ kswapd1/81 is trying to acquire lock: ffffffff8e7d2ed0 (cpu_hotplug_lock){++++}-{0:0}, at: acomp_ctx_get_cpu mm/zswap.c:886 [inline] ffffffff8e7d2ed0 (cpu_hotplug_lock){++++}-{0:0}, at: zswap_compress mm/zswap.c:908 [inline] ffffffff8e7d2ed0 (cpu_hotplug_lock){++++}-{0:0}, at: zswap_store_page mm/zswap.c:1439 [inline] ffffffff8e7d2ed0 (cpu_hotplug_lock){++++}-{0:0}, at: zswap_store+0xa74/0x1ba0 mm/zswap.c:1546 but task is already holding lock: ffffffff8ea36ea0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6871 [inline] ffffffff8ea36ea0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xbf1/0x36f0 mm/vmscan.c:7253 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (fs_reclaim){+.+.}-{0:0}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __fs_reclaim_acquire mm/page_alloc.c:3853 [inline] fs_reclaim_acquire+0x88/0x130 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] __do_kmalloc_node mm/slub.c:4297 [inline] __kmalloc_noprof+0xae/0x4c0 mm/slub.c:4310 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] __alloc_workqueue+0x10a/0x1f20 kernel/workqueue.c:5674 alloc_workqueue+0xd6/0x210 kernel/workqueue.c:5777 padata_alloc+0xc3/0x370 kernel/padata.c:1011 pcrypt_init_padata+0x27/0x100 crypto/pcrypt.c:331 pcrypt_init+0x65/0xe0 crypto/pcrypt.c:356 do_one_initcall+0x248/0x870 init/main.c:1266 do_initcall_level+0x157/0x210 init/main.c:1328 do_initcalls+0x3f/0x80 init/main.c:1344 kernel_init_freeable+0x435/0x5d0 init/main.c:1577 kernel_init+0x1d/0x2b0 init/main.c:1466 ret_from_fork+0x4b/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+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] cpus_read_lock+0x42/0x150 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+0xa74/0x1ba0 mm/zswap.c:1546 swap_writepage+0x647/0xce0 mm/page_io.c:279 shmem_writepage+0x1248/0x1610 mm/shmem.c:1579 pageout mm/vmscan.c:696 [inline] shrink_folio_list+0x3b68/0x5ca0 mm/vmscan.c:1374 evict_folios+0x3c86/0x5800 mm/vmscan.c:4600 try_to_shrink_lruvec+0x9a6/0xc70 mm/vmscan.c:4796 shrink_one+0x3b9/0x850 mm/vmscan.c:4841 shrink_many mm/vmscan.c:4904 [inline] lru_gen_shrink_node mm/vmscan.c:4982 [inline] shrink_node+0x37c5/0x3e50 mm/vmscan.c:5963 kswapd_shrink_node mm/vmscan.c:6792 [inline] balance_pgdat mm/vmscan.c:6984 [inline] kswapd+0x1ca9/0x36f0 mm/vmscan.c:7253 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/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 kswapd1/81: #0: ffffffff8ea36ea0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6871 [inline] #0: ffffffff8ea36ea0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xbf1/0x36f0 mm/vmscan.c:7253 stack backtrace: CPU: 0 UID: 0 PID: 81 Comm: kswapd1 Not tainted 6.13.0-rc6-syzkaller-gfbfd64d25c7a #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+0x241/0x360 lib/dump_stack.c:120 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074 check_noncircular+0x36a/0x4a0 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+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] cpus_read_lock+0x42/0x150 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+0xa74/0x1ba0 mm/zswap.c:1546 swap_writepage+0x647/0xce0 mm/page_io.c:279 shmem_writepage+0x1248/0x1610 mm/shmem.c:1579 pageout mm/vmscan.c:696 [inline] shrink_folio_list+0x3b68/0x5ca0 mm/vmscan.c:1374 evict_folios+0x3c86/0x5800 mm/vmscan.c:4600 try_to_shrink_lruvec+0x9a6/0xc70 mm/vmscan.c:4796 shrink_one+0x3b9/0x850 mm/vmscan.c:4841 shrink_many mm/vmscan.c:4904 [inline] lru_gen_shrink_node mm/vmscan.c:4982 [inline] shrink_node+0x37c5/0x3e50 mm/vmscan.c:5963 kswapd_shrink_node mm/vmscan.c:6792 [inline] balance_pgdat mm/vmscan.c:6984 [inline] kswapd+0x1ca9/0x36f0 mm/vmscan.c:7253 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244