====================================================== WARNING: possible circular locking dependency detected 6.12.0-rc3-syzkaller-00013-geca631b8fe80 #0 Not tainted ------------------------------------------------------ kswapd0/73 is trying to acquire lock: ffff888011a34610 (sb_internal#2){.+.+}-{0:0}, at: nilfs_dirty_inode+0x158/0x200 fs/nilfs2/inode.c:1110 but task is already holding lock: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6844 [inline] ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xbf1/0x3700 mm/vmscan.c:7226 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (fs_reclaim){+.+.}-{0:0}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 __fs_reclaim_acquire mm/page_alloc.c:3834 [inline] fs_reclaim_acquire+0x88/0x130 mm/page_alloc.c:3848 might_alloc include/linux/sched/mm.h:318 [inline] prepare_alloc_pages+0x147/0x5b0 mm/page_alloc.c:4493 __alloc_pages_noprof+0x16f/0x710 mm/page_alloc.c:4722 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265 alloc_pages_noprof mm/mempolicy.c:2345 [inline] folio_alloc_noprof+0x128/0x180 mm/mempolicy.c:2352 filemap_alloc_folio_noprof+0xdf/0x500 mm/filemap.c:1010 __filemap_get_folio+0x446/0xbd0 mm/filemap.c:1952 block_write_begin+0x66/0x120 fs/buffer.c:2226 nilfs_write_begin+0xa0/0x110 fs/nilfs2/inode.c:259 page_symlink+0x2a6/0x4a0 fs/namei.c:5362 nilfs_symlink+0x236/0x380 fs/nilfs2/namei.c:153 vfs_symlink+0x137/0x2e0 fs/namei.c:4615 do_symlinkat+0x222/0x3a0 fs/namei.c:4641 __do_sys_symlink fs/namei.c:4662 [inline] __se_sys_symlink fs/namei.c:4660 [inline] __x64_sys_symlink+0x7a/0x90 fs/namei.c:4660 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&nilfs->ns_segctor_sem){++++}-{3:3}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 down_read+0xb1/0xa40 kernel/locking/rwsem.c:1524 nilfs_transaction_begin+0x320/0x6e0 fs/nilfs2/segment.c:223 nilfs_symlink+0x135/0x380 fs/nilfs2/namei.c:140 vfs_symlink+0x137/0x2e0 fs/namei.c:4615 do_symlinkat+0x222/0x3a0 fs/namei.c:4641 __do_sys_symlink fs/namei.c:4662 [inline] __se_sys_symlink fs/namei.c:4660 [inline] __x64_sys_symlink+0x7a/0x90 fs/namei.c:4660 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (sb_internal#2){.+.+}-{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+0x1384/0x2050 kernel/locking/lockdep.c:5202 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1716 [inline] sb_start_intwrite include/linux/fs.h:1899 [inline] nilfs_transaction_begin+0x216/0x6e0 fs/nilfs2/segment.c:220 nilfs_dirty_inode+0x158/0x200 fs/nilfs2/inode.c:1110 __mark_inode_dirty+0x2ee/0xe90 fs/fs-writeback.c:2493 mark_inode_dirty_sync include/linux/fs.h:2479 [inline] iput+0x1f1/0xa50 fs/inode.c:1900 __dentry_kill+0x20d/0x630 fs/dcache.c:615 shrink_kill+0xa9/0x2c0 fs/dcache.c:1060 shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1087 prune_dcache_sb+0x10f/0x180 fs/dcache.c:1168 super_cache_scan+0x34f/0x4b0 fs/super.c:221 do_shrink_slab+0x701/0x1160 mm/shrinker.c:435 shrink_slab+0x1093/0x14d0 mm/shrinker.c:662 shrink_one+0x43b/0x850 mm/vmscan.c:4818 shrink_many mm/vmscan.c:4879 [inline] lru_gen_shrink_node mm/vmscan.c:4957 [inline] shrink_node+0x3799/0x3de0 mm/vmscan.c:5937 kswapd_shrink_node mm/vmscan.c:6765 [inline] balance_pgdat mm/vmscan.c:6957 [inline] kswapd+0x1ca3/0x3700 mm/vmscan.c:7226 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: Chain exists of: sb_internal#2 --> &nilfs->ns_segctor_sem --> fs_reclaim Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&nilfs->ns_segctor_sem); lock(fs_reclaim); rlock(sb_internal#2); *** DEADLOCK *** 2 locks held by kswapd0/73: #0: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6844 [inline] #0: ffffffff8ea37160 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xbf1/0x3700 mm/vmscan.c:7226 #1: ffff888011a340e0 (&type->s_umount_key#44){++++}-{3:3}, at: super_trylock_shared fs/super.c:562 [inline] #1: ffff888011a340e0 (&type->s_umount_key#44){++++}-{3:3}, at: super_cache_scan+0x94/0x4b0 fs/super.c:196 stack backtrace: CPU: 0 UID: 0 PID: 73 Comm: kswapd0 Not tainted 6.12.0-rc3-syzkaller-00013-geca631b8fe80 #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+0x1384/0x2050 kernel/locking/lockdep.c:5202 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1716 [inline] sb_start_intwrite include/linux/fs.h:1899 [inline] nilfs_transaction_begin+0x216/0x6e0 fs/nilfs2/segment.c:220 nilfs_dirty_inode+0x158/0x200 fs/nilfs2/inode.c:1110 __mark_inode_dirty+0x2ee/0xe90 fs/fs-writeback.c:2493 mark_inode_dirty_sync include/linux/fs.h:2479 [inline] iput+0x1f1/0xa50 fs/inode.c:1900 __dentry_kill+0x20d/0x630 fs/dcache.c:615 shrink_kill+0xa9/0x2c0 fs/dcache.c:1060 shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1087 prune_dcache_sb+0x10f/0x180 fs/dcache.c:1168 super_cache_scan+0x34f/0x4b0 fs/super.c:221 do_shrink_slab+0x701/0x1160 mm/shrinker.c:435 shrink_slab+0x1093/0x14d0 mm/shrinker.c:662 shrink_one+0x43b/0x850 mm/vmscan.c:4818 shrink_many mm/vmscan.c:4879 [inline] lru_gen_shrink_node mm/vmscan.c:4957 [inline] shrink_node+0x3799/0x3de0 mm/vmscan.c:5937 kswapd_shrink_node mm/vmscan.c:6765 [inline] balance_pgdat mm/vmscan.c:6957 [inline] kswapd+0x1ca3/0x3700 mm/vmscan.c:7226 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