[syzbot] [nilfs?] possible deadlock in nilfs_dirty_inode

[syzbot <syzbot+903a7b353239d83ad434-Pl5Pbv+GP7P466ipTTIvnc23WoclnBCfAL8bYrjMMd8@public.gmane.org>]

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-Pl5Pbv+GP7P466ipTTIvnc23WoclnBCfAL8bYrjMMd8@public.gmane.org

======================================================
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>


---
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