Kernel bug: possible deadlock in f2fs_evict_inode
Subsystem: f2fs
Status: fixed

Crash report:
======================================================
WARNING: possible circular locking dependency detected
6.12.0-rc1-syzkaller-00114-g3840cbe24cf0 #0 Not tainted
------------------------------------------------------
kswapd0/79 is trying to acquire lock:
ffff888057a62610 (sb_internal#2){.+.+}-{0:0}, at: f2fs_evict_inode+0x662/0x15c0 fs/f2fs/inode.c:842

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+0x88/0x140 mm/page_alloc.c:3848
       might_alloc include/linux/sched/mm.h:327 [inline]
       prepare_alloc_pages+0x147/0x5d0 mm/page_alloc.c:4493
       __alloc_pages_noprof+0x166/0x6c0 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
       do_read_cache_folio+0x2eb/0x850 mm/filemap.c:3787
       read_mapping_folio include/linux/pagemap.h:1011 [inline]
       f2fs_commit_super+0x52b/0x7d0 fs/f2fs/super.c:4044
       f2fs_record_stop_reason+0x13b/0x1d0 fs/f2fs/super.c:4079
       f2fs_handle_critical_error+0x2ac/0x5c0 fs/f2fs/super.c:4174
       f2fs_write_inode+0x35f/0x4d0 fs/f2fs/inode.c:785
       f2fs_do_sync_file+0x1395/0x19f0 fs/f2fs/file.c:356
       f2fs_ioc_commit_atomic_write fs/f2fs/file.c:2259 [inline]
       __f2fs_ioctl+0x49db/0xb8f0 fs/f2fs/file.c:4417
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:907 [inline]
       __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893
       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 (&sbi->sb_lock){++++}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
       down_write+0x99/0x220 kernel/locking/rwsem.c:1577
       f2fs_down_write fs/f2fs/f2fs.h:2199 [inline]
       f2fs_record_errors fs/f2fs/super.c:4121 [inline]
       f2fs_handle_error+0xf6/0x250 fs/f2fs/super.c:4138
       __get_node_page+0x8d0/0xfc0 fs/f2fs/node.c:1489
       f2fs_update_inode_page+0x87/0x170 fs/f2fs/inode.c:746
       f2fs_evict_inode+0xa61/0x15c0 fs/f2fs/inode.c:883
       evict+0x4e8/0x9b0 fs/inode.c:723
       do_unlinkat+0x512/0x830 fs/namei.c:4540
       __do_sys_unlink fs/namei.c:4581 [inline]
       __se_sys_unlink fs/namei.c:4579 [inline]
       __x64_sys_unlink+0x47/0x50 fs/namei.c:4579
       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+0x4d/0x1c0 include/linux/fs.h:1899
       f2fs_evict_inode+0x662/0x15c0 fs/f2fs/inode.c:842
       evict+0x4e8/0x9b0 fs/inode.c:723
       f2fs_evict_inode+0x1a4/0x15c0 fs/f2fs/inode.c:807
       evict+0x4e8/0x9b0 fs/inode.c:723
       dispose_list fs/inode.c:772 [inline]
       prune_icache_sb+0x239/0x2f0 fs/inode.c:961
       super_cache_scan+0x38c/0x4b0 fs/super.c:223
       do_shrink_slab+0x701/0x1160 mm/shrinker.c:435
       shrink_slab_memcg mm/shrinker.c:548 [inline]
       shrink_slab+0x878/0x14d0 mm/shrinker.c:626
       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 --> &sbi->sb_lock --> fs_reclaim

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(fs_reclaim);
                               lock(&sbi->sb_lock);
                               lock(fs_reclaim);
  rlock(sb_internal#2);

 *** DEADLOCK ***

2 locks held by kswapd0/79:
 #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: ffff888057a620e0 (&type->s_umount_key#54){++++}-{3:3}, at: super_trylock_shared fs/super.c:562 [inline]
 #1: ffff888057a620e0 (&type->s_umount_key#54){++++}-{3:3}, at: super_cache_scan+0x94/0x4b0 fs/super.c:196

stack backtrace:
CPU: 0 UID: 0 PID: 79 Comm: kswapd0 Not tainted 6.12.0-rc1-syzkaller-00114-g3840cbe24cf0 #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:
 <TASK>
 __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+0x4d/0x1c0 include/linux/fs.h:1899
 f2fs_evict_inode+0x662/0x15c0 fs/f2fs/inode.c:842
 evict+0x4e8/0x9b0 fs/inode.c:723
 f2fs_evict_inode+0x1a4/0x15c0 fs/f2fs/inode.c:807
 evict+0x4e8/0x9b0 fs/inode.c:723
 dispose_list fs/inode.c:772 [inline]
 prune_icache_sb+0x239/0x2f0 fs/inode.c:961
 super_cache_scan+0x38c/0x4b0 fs/super.c:223
 do_shrink_slab+0x701/0x1160 mm/shrinker.c:435
 shrink_slab_memcg mm/shrinker.c:548 [inline]
 shrink_slab+0x878/0x14d0 mm/shrinker.c:626
 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
 </TASK>