Hello, syzbot found the following issue on: HEAD commit: dad9774deaf1 Merge tag 'timers-urgent-2023-06-21' of git:/.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=106a4b33280000 kernel config: https://syzkaller.appspot.com/x/.config?x=2cbd298d0aff1140 dashboard link: https://syzkaller.appspot.com/bug?extid=903a7b353239d83ad434 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 userspace arch: i386 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-dad9774d.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/04ba8cb302c4/vmlinux-dad9774d.xz kernel image: https://storage.googleapis.com/syzbot-assets/9b26d41c591b/bzImage-dad9774d.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+903a7b353239d83ad434@xxxxxxxxxxxxxxxxxxxxxxxxx ====================================================== WARNING: possible circular locking dependency detected 6.4.0-rc7-syzkaller-00072-gdad9774deaf1 #0 Not tainted ------------------------------------------------------ kswapd0/111 is trying to acquire lock: ffff888050c6e650 (sb_internal#3){.+.+}-{0:0}, at: nilfs_dirty_inode+0x18a/0x260 fs/nilfs2/inode.c:1147 but task is already holding lock: ffffffff8c8efae0 (fs_reclaim){+.+.}-{0:0}, at: set_task_reclaim_state mm/vmscan.c:512 [inline] ffffffff8c8efae0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x170/0x1ac0 mm/vmscan.c:7349 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (fs_reclaim){+.+.}-{0:0}: __fs_reclaim_acquire mm/page_alloc.c:3893 [inline] fs_reclaim_acquire+0x11d/0x160 mm/page_alloc.c:3907 might_alloc include/linux/sched/mm.h:303 [inline] prepare_alloc_pages+0x159/0x570 mm/page_alloc.c:4539 __alloc_pages+0x149/0x4a0 mm/page_alloc.c:4757 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2279 folio_alloc+0x20/0x70 mm/mempolicy.c:2289 filemap_alloc_folio+0x3c1/0x470 mm/filemap.c:976 __filemap_get_folio+0x2a6/0x990 mm/filemap.c:1971 pagecache_get_page+0x2e/0x270 mm/folio-compat.c:99 block_write_begin+0x35/0x4d0 fs/buffer.c:2171 nilfs_write_begin+0xa0/0x1a0 fs/nilfs2/inode.c:261 page_symlink+0x386/0x480 fs/namei.c:5193 nilfs_symlink+0x235/0x3c0 fs/nilfs2/namei.c:153 vfs_symlink fs/namei.c:4475 [inline] vfs_symlink+0x10c/0x2c0 fs/namei.c:4459 do_symlinkat+0x262/0x2e0 fs/namei.c:4501 __do_sys_symlinkat fs/namei.c:4517 [inline] __se_sys_symlinkat fs/namei.c:4514 [inline] __ia32_sys_symlinkat+0x97/0xc0 fs/namei.c:4514 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 -> #1 (&nilfs->ns_segctor_sem){++++}-{3:3}: down_read+0x9c/0x480 kernel/locking/rwsem.c:1520 nilfs_transaction_begin+0x31a/0xa20 fs/nilfs2/segment.c:223 nilfs_create+0x9b/0x300 fs/nilfs2/namei.c:82 lookup_open.isra.0+0x105a/0x1400 fs/namei.c:3492 open_last_lookups fs/namei.c:3560 [inline] path_openat+0x975/0x2750 fs/namei.c:3788 do_filp_open+0x1ba/0x410 fs/namei.c:3818 do_sys_openat2+0x16d/0x4c0 fs/open.c:1356 do_sys_open fs/open.c:1372 [inline] __do_compat_sys_open fs/open.c:1423 [inline] __se_compat_sys_open fs/open.c:1421 [inline] __ia32_compat_sys_open+0x11d/0x1c0 fs/open.c:1421 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 -> #0 (sb_internal#3){.+.+}-{0:0}: check_prev_add kernel/locking/lockdep.c:3113 [inline] check_prevs_add kernel/locking/lockdep.c:3232 [inline] validate_chain kernel/locking/lockdep.c:3847 [inline] __lock_acquire+0x2fcd/0x5f30 kernel/locking/lockdep.c:5088 lock_acquire kernel/locking/lockdep.c:5705 [inline] lock_acquire+0x1b1/0x520 kernel/locking/lockdep.c:5670 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1494 [inline] sb_start_intwrite include/linux/fs.h:1616 [inline] nilfs_transaction_begin+0x21e/0xa20 fs/nilfs2/segment.c:220 nilfs_dirty_inode+0x18a/0x260 fs/nilfs2/inode.c:1147 __mark_inode_dirty+0x1e0/0xd60 fs/fs-writeback.c:2424 mark_inode_dirty_sync include/linux/fs.h:2149 [inline] iput.part.0+0x57/0x740 fs/inode.c:1770 iput+0x5c/0x80 fs/inode.c:1763 dentry_unlink_inode+0x2b1/0x460 fs/dcache.c:401 __dentry_kill+0x3c0/0x640 fs/dcache.c:607 shrink_dentry_list+0x12c/0x4f0 fs/dcache.c:1201 prune_dcache_sb+0xeb/0x150 fs/dcache.c:1282 super_cache_scan+0x33a/0x590 fs/super.c:104 do_shrink_slab+0x428/0xaa0 mm/vmscan.c:895 shrink_slab_memcg mm/vmscan.c:964 [inline] shrink_slab+0x38f/0x6c0 mm/vmscan.c:1043 shrink_one+0x4f9/0x710 mm/vmscan.c:5365 shrink_many mm/vmscan.c:5415 [inline] lru_gen_shrink_node mm/vmscan.c:5532 [inline] shrink_node+0x1fd5/0x3500 mm/vmscan.c:6473 kswapd_shrink_node mm/vmscan.c:7273 [inline] balance_pgdat+0xa02/0x1ac0 mm/vmscan.c:7463 kswapd+0x677/0xd60 mm/vmscan.c:7723 kthread+0x344/0x440 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 other info that might help us debug this: Chain exists of: sb_internal#3 --> &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#3); *** DEADLOCK *** 3 locks held by kswapd0/111: #0: ffffffff8c8efae0 (fs_reclaim){+.+.}-{0:0}, at: set_task_reclaim_state mm/vmscan.c:512 [inline] #0: ffffffff8c8efae0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x170/0x1ac0 mm/vmscan.c:7349 #1: ffffffff8c8a3b10 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab_memcg mm/vmscan.c:937 [inline] #1: ffffffff8c8a3b10 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x2a0/0x6c0 mm/vmscan.c:1043 #2: ffff888050c6e0e0 (&type->s_umount_key#61){++++}-{3:3}, at: trylock_super fs/super.c:414 [inline] #2: ffff888050c6e0e0 (&type->s_umount_key#61){++++}-{3:3}, at: super_cache_scan+0x70/0x590 fs/super.c:79 stack backtrace: CPU: 0 PID: 111 Comm: kswapd0 Not tainted 6.4.0-rc7-syzkaller-00072-gdad9774deaf1 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2188 check_prev_add kernel/locking/lockdep.c:3113 [inline] check_prevs_add kernel/locking/lockdep.c:3232 [inline] validate_chain kernel/locking/lockdep.c:3847 [inline] __lock_acquire+0x2fcd/0x5f30 kernel/locking/lockdep.c:5088 lock_acquire kernel/locking/lockdep.c:5705 [inline] lock_acquire+0x1b1/0x520 kernel/locking/lockdep.c:5670 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1494 [inline] sb_start_intwrite include/linux/fs.h:1616 [inline] nilfs_transaction_begin+0x21e/0xa20 fs/nilfs2/segment.c:220 nilfs_dirty_inode+0x18a/0x260 fs/nilfs2/inode.c:1147 __mark_inode_dirty+0x1e0/0xd60 fs/fs-writeback.c:2424 mark_inode_dirty_sync include/linux/fs.h:2149 [inline] iput.part.0+0x57/0x740 fs/inode.c:1770 iput+0x5c/0x80 fs/inode.c:1763 dentry_unlink_inode+0x2b1/0x460 fs/dcache.c:401 __dentry_kill+0x3c0/0x640 fs/dcache.c:607 shrink_dentry_list+0x12c/0x4f0 fs/dcache.c:1201 prune_dcache_sb+0xeb/0x150 fs/dcache.c:1282 super_cache_scan+0x33a/0x590 fs/super.c:104 do_shrink_slab+0x428/0xaa0 mm/vmscan.c:895 shrink_slab_memcg mm/vmscan.c:964 [inline] shrink_slab+0x38f/0x6c0 mm/vmscan.c:1043 shrink_one+0x4f9/0x710 mm/vmscan.c:5365 shrink_many mm/vmscan.c:5415 [inline] lru_gen_shrink_node mm/vmscan.c:5532 [inline] shrink_node+0x1fd5/0x3500 mm/vmscan.c:6473 kswapd_shrink_node mm/vmscan.c:7273 [inline] balance_pgdat+0xa02/0x1ac0 mm/vmscan.c:7463 kswapd+0x677/0xd60 mm/vmscan.c:7723 kthread+0x344/0x440 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 </TASK> --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the bug is already fixed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to change bug's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the bug is a duplicate of another bug, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
