f2fs: fix to avoid potential deadlock in f2fs_record_stop_reason()

In the Linux kernel, the following vulnerability has been resolved:

f2fs: fix to avoid potential deadlock in f2fs_record_stop_reason()

syzbot reports deadlock issue of f2fs as below:

======================================================

WARNING: possible circular locking dependency detected

6.12.0-rc3-syzkaller-00087-gc964ced77262 #0 Not tainted

------------------------------------------------------

kswapd0/79 is trying to acquire lock:

ffff888011824088 (&sbi->sb_lock){++++}-{3:3}, at: f2fs_down_write fs/f2fs/f2fs.h:2199 [inline]

ffff888011824088 (&sbi->sb_lock){++++}-{3:3}, at: f2fs_record_stop_reason+0x52/0x1d0 fs/f2fs/super.c:4068

but task is already holding lock:

ffff88804bd92610 (sb_internal#2){.+.+}-{0:0}, at: f2fs_evict_inode+0x662/0x15c0 fs/f2fs/inode.c:842

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (sb_internal#2){.+.+}-{0:0}:

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:725

f2fs_evict_inode+0x1a4/0x15c0 fs/f2fs/inode.c:807

evict+0x4e8/0x9b0 fs/inode.c:725

dispose_list fs/inode.c:774 [inline]

prune_icache_sb+0x239/0x2f0 fs/inode.c:963

super_cache_scan+0x38c/0x4b0 fs/super.c:223

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

-> #1 (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

do_read_cache_folio+0x2eb/0x850 mm/filemap.c:3787

read_mapping_folio include/linux/pagemap.h:1011 [inline]

f2fs_commit_super+0x3c0/0x7d0 fs/f2fs/super.c:4032

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

write_inode fs/fs-writeback.c:1503 [inline]

__writeback_single_inode+0x711/0x10d0 fs/fs-writeback.c:1723

writeback_single_inode+0x1f3/0x660 fs/fs-writeback.c:1779

sync_inode_metadata+0xc4/0x120 fs/fs-writeback.c:2849

f2fs_release_file+0xa8/0x100 fs/f2fs/file.c:1941

__fput+0x23f/0x880 fs/file_table.c:431

task_work_run+0x24f/0x310 kernel/task_work.c:228

resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]

exit_to_user_mode_loop kernel/entry/common.c:114 [inline]

exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]

__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]

syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218

do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89

entry_SYSCALL_64_after_hwframe+0x77/0x7f

---truncated---