====================================================== WARNING: possible circular locking dependency detected 6.8.0-rc7-syzkaller #0 Not tainted ------------------------------------------------------ kswapd0/88 is trying to acquire lock: ffff88802fd12950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x203c/0x22a0 fs/jbd2/transaction.c:463 but task is already holding lock: ffffffff8e219320 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6771 [inline] ffffffff8e219320 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb3e/0x36d0 mm/vmscan.c:7143 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (fs_reclaim){+.+.}-{0:0}: lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754 __fs_reclaim_acquire mm/page_alloc.c:3692 [inline] fs_reclaim_acquire+0x87/0x130 mm/page_alloc.c:3706 might_alloc include/linux/sched/mm.h:303 [inline] slab_pre_alloc_hook mm/slub.c:3761 [inline] slab_alloc_node mm/slub.c:3842 [inline] kmem_cache_alloc+0x48/0x340 mm/slub.c:3867 ext4_es_insert_delayed_block+0x2d9/0xa10 fs/ext4/extents_status.c:2090 ext4_insert_delayed_block fs/ext4/inode.c:1676 [inline] ext4_da_map_blocks fs/ext4/inode.c:1777 [inline] ext4_da_get_block_prep+0xa67/0x1420 fs/ext4/inode.c:1817 ext4_block_write_begin+0x53d/0x1850 fs/ext4/inode.c:1055 ext4_da_write_begin+0x5e8/0xa50 fs/ext4/inode.c:2894 generic_perform_write+0x323/0x640 mm/filemap.c:3930 ext4_buffered_write_iter+0xc6/0x350 fs/ext4/file.c:299 ext4_file_write_iter+0x1dc/0x19c0 do_iter_readv_writev+0x46e/0x640 vfs_writev+0x395/0xbb0 fs/read_write.c:971 do_pwritev fs/read_write.c:1072 [inline] __do_sys_pwritev2 fs/read_write.c:1131 [inline] __se_sys_pwritev2+0x1ca/0x2d0 fs/read_write.c:1122 do_syscall_64+0xfb/0x240 entry_SYSCALL_64_after_hwframe+0x6f/0x77 -> #1 (&ei->i_data_sem){++++}-{3:3}: lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754 down_write+0x3a/0x50 kernel/locking/rwsem.c:1579 ext4_map_blocks+0x988/0x1d20 fs/ext4/inode.c:616 mpage_map_one_extent fs/ext4/inode.c:2163 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2216 [inline] ext4_do_writepages+0x15e7/0x3ca0 fs/ext4/inode.c:2679 ext4_writepages+0x203/0x3e0 fs/ext4/inode.c:2768 do_writepages+0x3ac/0x680 mm/page-writeback.c:2553 __writeback_single_inode+0x155/0xfd0 fs/fs-writeback.c:1625 writeback_sb_inodes+0x8e3/0x1220 fs/fs-writeback.c:1916 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:1987 wb_writeback+0x461/0xc80 fs/fs-writeback.c:2094 wb_check_background_flush fs/fs-writeback.c:2164 [inline] wb_do_writeback fs/fs-writeback.c:2252 [inline] wb_workfn+0xc33/0xfb0 fs/fs-writeback.c:2279 process_one_work kernel/workqueue.c:2633 [inline] process_scheduled_works+0x915/0x1420 kernel/workqueue.c:2706 worker_thread+0xa5f/0x1000 kernel/workqueue.c:2787 kthread+0x2f1/0x390 kernel/kthread.c:388 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:243 -> #0 (jbd2_handle){++++}-{0:0}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x18ca/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1345/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754 start_this_handle+0x205c/0x22a0 fs/jbd2/transaction.c:463 jbd2__journal_start+0x2d9/0x5d0 fs/jbd2/transaction.c:520 __ext4_journal_start_sb+0x215/0x5b0 fs/ext4/ext4_jbd2.c:112 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline] ext4_dirty_inode+0x92/0x110 fs/ext4/inode.c:5939 __mark_inode_dirty+0x30b/0xdb0 fs/fs-writeback.c:2452 mark_inode_dirty_sync include/linux/fs.h:2387 [inline] iput+0x1f2/0x900 fs/inode.c:1762 __dentry_kill+0x20d/0x630 fs/dcache.c:603 shrink_kill+0xa9/0x2c0 fs/dcache.c:1048 shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1075 prune_dcache_sb+0x10f/0x180 fs/dcache.c:1156 super_cache_scan+0x34f/0x4b0 fs/super.c:221 do_shrink_slab+0x6d2/0x1140 mm/shrinker.c:435 shrink_slab+0x1092/0x14d0 mm/shrinker.c:662 shrink_one+0x423/0x7e0 mm/vmscan.c:4767 shrink_many mm/vmscan.c:4828 [inline] lru_gen_shrink_node mm/vmscan.c:4929 [inline] shrink_node+0x375e/0x3e20 mm/vmscan.c:5888 kswapd_shrink_node mm/vmscan.c:6693 [inline] balance_pgdat mm/vmscan.c:6883 [inline] kswapd+0x17d0/0x36d0 mm/vmscan.c:7143 kthread+0x2f1/0x390 kernel/kthread.c:388 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:243 other info that might help us debug this: Chain exists of: jbd2_handle --> &ei->i_data_sem --> fs_reclaim Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&ei->i_data_sem); lock(fs_reclaim); rlock(jbd2_handle); *** DEADLOCK *** 2 locks held by kswapd0/88: #0: ffffffff8e219320 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6771 [inline] #0: ffffffff8e219320 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb3e/0x36d0 mm/vmscan.c:7143 #1: ffff88802ff760e0 (&type->s_umount_key#31){++++}-{3:3}, at: super_trylock_shared fs/super.c:561 [inline] #1: ffff88802ff760e0 (&type->s_umount_key#31){++++}-{3:3}, at: super_cache_scan+0x94/0x4b0 fs/super.c:196 stack backtrace: CPU: 1 PID: 88 Comm: kswapd0 Not tainted 6.8.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x18ca/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1345/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754 start_this_handle+0x205c/0x22a0 fs/jbd2/transaction.c:463 jbd2__journal_start+0x2d9/0x5d0 fs/jbd2/transaction.c:520 __ext4_journal_start_sb+0x215/0x5b0 fs/ext4/ext4_jbd2.c:112 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline] ext4_dirty_inode+0x92/0x110 fs/ext4/inode.c:5939 __mark_inode_dirty+0x30b/0xdb0 fs/fs-writeback.c:2452 mark_inode_dirty_sync include/linux/fs.h:2387 [inline] iput+0x1f2/0x900 fs/inode.c:1762 __dentry_kill+0x20d/0x630 fs/dcache.c:603 shrink_kill+0xa9/0x2c0 fs/dcache.c:1048 shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1075 prune_dcache_sb+0x10f/0x180 fs/dcache.c:1156 super_cache_scan+0x34f/0x4b0 fs/super.c:221 do_shrink_slab+0x6d2/0x1140 mm/shrinker.c:435 shrink_slab+0x1092/0x14d0 mm/shrinker.c:662 shrink_one+0x423/0x7e0 mm/vmscan.c:4767 shrink_many mm/vmscan.c:4828 [inline] lru_gen_shrink_node mm/vmscan.c:4929 [inline] shrink_node+0x375e/0x3e20 mm/vmscan.c:5888 kswapd_shrink_node mm/vmscan.c:6693 [inline] balance_pgdat mm/vmscan.c:6883 [inline] kswapd+0x17d0/0x36d0 mm/vmscan.c:7143 kthread+0x2f1/0x390 kernel/kthread.c:388 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:243