[syzbot] [ext4?] possible deadlock in start_this_handle (4)

From: syzbot
Date: Tue Feb 28 2023 - 19:02:44 EST

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Hello,

syzbot found the following issue on:

HEAD commit: a93e884edf61 Merge tag 'driver-core-6.3-rc1' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11b9dea8c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=537cd86b8ac8f12d
dashboard link: https://syzkaller.appspot.com/bug?extid=cf0b4280f19be4031cf2
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.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cf0b4280f19be4031cf2@xxxxxxxxxxxxxxxxxxxxxxxxx

======================================================
WARNING: possible circular locking dependency detected
6.2.0-syzkaller-10217-ga93e884edf61 #0 Not tainted
------------------------------------------------------
kswapd0/100 is trying to acquire lock:
ffff888043c64990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xfb4/0x14e0 fs/jbd2/transaction.c:461

but task is already holding lock:
ffffffff8c8e9ae0 (fs_reclaim){+.+.}-{0:0}, at: set_task_reclaim_state mm/vmscan.c:200 [inline]
ffffffff8c8e9ae0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x170/0x1ac0 mm/vmscan.c:7338

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:4716 [inline]
fs_reclaim_acquire+0x11d/0x160 mm/page_alloc.c:4730
might_alloc include/linux/sched/mm.h:271 [inline]
slab_pre_alloc_hook mm/slab.h:728 [inline]
slab_alloc_node mm/slub.c:3434 [inline]
__kmem_cache_alloc_node+0x41/0x330 mm/slub.c:3491
kmalloc_node_trace+0x21/0x60 mm/slab_common.c:1074
kmalloc_node include/linux/slab.h:606 [inline]
kzalloc_node include/linux/slab.h:731 [inline]
mempool_create_node mm/mempool.c:272 [inline]
mempool_create+0x52/0xc0 mm/mempool.c:261
mempool_create_page_pool include/linux/mempool.h:112 [inline]
fscrypt_initialize+0x8a/0xa0 fs/crypto/crypto.c:332
fscrypt_setup_encryption_info+0xef/0xeb0 fs/crypto/keysetup.c:563
fscrypt_get_encryption_info+0x375/0x450 fs/crypto/keysetup.c:668
fscrypt_setup_filename+0x23c/0xec0 fs/crypto/fname.c:458
__fscrypt_prepare_lookup+0x2c/0xf0 fs/crypto/hooks.c:100
fscrypt_prepare_lookup include/linux/fscrypt.h:935 [inline]
ext4_fname_prepare_lookup+0x1be/0x200 fs/ext4/crypto.c:46
ext4_lookup_entry fs/ext4/namei.c:1745 [inline]
ext4_lookup fs/ext4/namei.c:1820 [inline]
ext4_lookup+0x131/0x700 fs/ext4/namei.c:1811
__lookup_slow+0x24c/0x460 fs/namei.c:1686
lookup_slow fs/namei.c:1703 [inline]
walk_component+0x33f/0x5a0 fs/namei.c:1994
lookup_last fs/namei.c:2451 [inline]
path_lookupat+0x1ba/0x840 fs/namei.c:2475
filename_lookup+0x1d2/0x590 fs/namei.c:2504
user_path_at_empty+0x46/0x60 fs/namei.c:2877
user_path_at include/linux/namei.h:57 [inline]
__do_sys_chdir fs/open.c:515 [inline]
__se_sys_chdir fs/open.c:509 [inline]
__ia32_sys_chdir+0xbb/0x260 fs/open.c:509
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 (fscrypt_init_mutex){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747
fscrypt_initialize+0x40/0xa0 fs/crypto/crypto.c:326
fscrypt_setup_encryption_info+0xef/0xeb0 fs/crypto/keysetup.c:563
fscrypt_get_encryption_info+0x375/0x450 fs/crypto/keysetup.c:668
fscrypt_setup_filename+0x23c/0xec0 fs/crypto/fname.c:458
ext4_fname_setup_filename+0x8c/0x110 fs/ext4/crypto.c:28
ext4_add_entry+0x3aa/0xe30 fs/ext4/namei.c:2380
ext4_rename+0x1979/0x2620 fs/ext4/namei.c:3904
ext4_rename2+0x1c7/0x270 fs/ext4/namei.c:4184
vfs_rename+0xef6/0x17a0 fs/namei.c:4772
do_renameat2+0xb62/0xc90 fs/namei.c:4923
__do_sys_renameat2 fs/namei.c:4956 [inline]
__se_sys_renameat2 fs/namei.c:4953 [inline]
__ia32_sys_renameat2+0xe8/0x120 fs/namei.c:4953
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 (jbd2_handle){++++}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain kernel/locking/lockdep.c:3832 [inline]
__lock_acquire+0x2ec7/0x5d40 kernel/locking/lockdep.c:5056
lock_acquire kernel/locking/lockdep.c:5669 [inline]
lock_acquire+0x1e3/0x670 kernel/locking/lockdep.c:5634
start_this_handle+0xfe7/0x14e0 fs/jbd2/transaction.c:463
jbd2__journal_start+0x39d/0x9d0 fs/jbd2/transaction.c:520
__ext4_journal_start_sb+0x706/0x890 fs/ext4/ext4_jbd2.c:111
__ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
ext4_dirty_inode+0xa5/0x130 fs/ext4/inode.c:6107
__mark_inode_dirty+0x247/0x1250 fs/fs-writeback.c:2421
mark_inode_dirty_sync include/linux/fs.h:2132 [inline]
iput.part.0+0x57/0x8a0 fs/inode.c:1771
iput+0x5c/0x80 fs/inode.c:1764
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+0x464/0xd20 mm/vmscan.c:853
shrink_slab_memcg mm/vmscan.c:922 [inline]
shrink_slab+0x388/0x660 mm/vmscan.c:1001
shrink_one+0x502/0x810 mm/vmscan.c:5343
shrink_many mm/vmscan.c:5394 [inline]
lru_gen_shrink_node mm/vmscan.c:5511 [inline]
shrink_node+0x2064/0x35f0 mm/vmscan.c:6459
kswapd_shrink_node mm/vmscan.c:7262 [inline]
balance_pgdat+0xa02/0x1ac0 mm/vmscan.c:7452
kswapd+0x70b/0x1000 mm/vmscan.c:7712
kthread+0x2e8/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

other info that might help us debug this:

Chain exists of:
jbd2_handle --> fscrypt_init_mutex --> fs_reclaim

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(fscrypt_init_mutex);
lock(fs_reclaim);
lock(jbd2_handle);

*** DEADLOCK ***

3 locks held by kswapd0/100:
#0: ffffffff8c8e9ae0 (fs_reclaim){+.+.}-{0:0}, at: set_task_reclaim_state mm/vmscan.c:200 [inline]
#0: ffffffff8c8e9ae0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x170/0x1ac0 mm/vmscan.c:7338
#1: ffffffff8c8a06d0 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab_memcg mm/vmscan.c:895 [inline]
#1: ffffffff8c8a06d0 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x2a0/0x660 mm/vmscan.c:1001
#2: ffff88801b18a0e0 (&type->s_umount_key#31){++++}-{3:3}, at: trylock_super fs/super.c:414 [inline]
#2: ffff88801b18a0e0 (&type->s_umount_key#31){++++}-{3:3}, at: super_cache_scan+0x70/0x590 fs/super.c:79

stack backtrace:
CPU: 1 PID: 100 Comm: kswapd0 Not tainted 6.2.0-syzkaller-10217-ga93e884edf61 #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:2178
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain kernel/locking/lockdep.c:3832 [inline]
__lock_acquire+0x2ec7/0x5d40 kernel/locking/lockdep.c:5056
lock_acquire kernel/locking/lockdep.c:5669 [inline]
lock_acquire+0x1e3/0x670 kernel/locking/lockdep.c:5634
start_this_handle+0xfe7/0x14e0 fs/jbd2/transaction.c:463
jbd2__journal_start+0x39d/0x9d0 fs/jbd2/transaction.c:520
__ext4_journal_start_sb+0x706/0x890 fs/ext4/ext4_jbd2.c:111
__ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
ext4_dirty_inode+0xa5/0x130 fs/ext4/inode.c:6107
__mark_inode_dirty+0x247/0x1250 fs/fs-writeback.c:2421
mark_inode_dirty_sync include/linux/fs.h:2132 [inline]
iput.part.0+0x57/0x8a0 fs/inode.c:1771
iput+0x5c/0x80 fs/inode.c:1764
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+0x464/0xd20 mm/vmscan.c:853
shrink_slab_memcg mm/vmscan.c:922 [inline]
shrink_slab+0x388/0x660 mm/vmscan.c:1001
shrink_one+0x502/0x810 mm/vmscan.c:5343
shrink_many mm/vmscan.c:5394 [inline]
lru_gen_shrink_node mm/vmscan.c:5511 [inline]
shrink_node+0x2064/0x35f0 mm/vmscan.c:6459
kswapd_shrink_node mm/vmscan.c:7262 [inline]
balance_pgdat+0xa02/0x1ac0 mm/vmscan.c:7452
kswapd+0x70b/0x1000 mm/vmscan.c:7712
kthread+0x2e8/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
</TASK>

---
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Next message: Brian Gerst: "Re: [PATCH v12 07/11] x86/smpboot: Remove early_gdt_descr on 64-bit"
Previous message: Dave Chinner: "Re: [syzbot] [ext4?] possible deadlock in evict (3)"
Next in thread: Eric Biggers: "Re: [syzbot] [ext4?] possible deadlock in start_this_handle (4)"
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