[syzbot] [fscrypt?] possible deadlock in fscrypt_initialize (2)

From: syzbot
Date: Wed Mar 01 2023 - 10:05:08 EST

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Hello,

syzbot found the following issue on:

HEAD commit: c0927a7a5391 Merge tag 'xfs-6.3-merge-4' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1268a838c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=cab35c936731a347
dashboard link: https://syzkaller.appspot.com/bug?extid=3a3b5221ffafba7d5204
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+3a3b5221ffafba7d5204@xxxxxxxxxxxxxxxxxxxxxxxxx

syz-executor.3 (pid 10194) is setting deprecated v1 encryption policy; recommend upgrading to v2.
======================================================
WARNING: possible circular locking dependency detected
6.2.0-syzkaller-12998-gc0927a7a5391 #0 Not tainted
------------------------------------------------------
syz-executor.3/10194 is trying to acquire lock:
ffffffff8c972128 (fscrypt_init_mutex){+.+.}-{3:3}, at: fscrypt_initialize+0x40/0xa0 fs/crypto/crypto.c:326

but task is already holding lock:
ffff888044f84990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xfb4/0x14e0 fs/jbd2/transaction.c:461

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #3 (jbd2_handle){++++}-{0:0}:
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_sample_last_mounted fs/ext4/file.c:851 [inline]
ext4_file_open+0x618/0xbf0 fs/ext4/file.c:880
do_dentry_open+0x6cc/0x13f0 fs/open.c:920
do_open fs/namei.c:3560 [inline]
path_openat+0x1baa/0x2750 fs/namei.c:3715
do_filp_open+0x1ba/0x410 fs/namei.c:3742
do_sys_openat2+0x16d/0x4c0 fs/open.c:1348
do_sys_open fs/open.c:1364 [inline]
__do_sys_openat fs/open.c:1380 [inline]
__se_sys_openat fs/open.c:1375 [inline]
__x64_sys_openat+0x143/0x1f0 fs/open.c:1375
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #2 (sb_internal){.+.+}-{0:0}:
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1477 [inline]
sb_start_intwrite include/linux/fs.h:1599 [inline]
ext4_evict_inode+0xfc7/0x1b50 fs/ext4/inode.c:240
evict+0x2ed/0x6b0 fs/inode.c:665
iput_final fs/inode.c:1748 [inline]
iput.part.0+0x59b/0x8a0 fs/inode.c:1774
iput+0x5c/0x80 fs/inode.c:1764
dentry_unlink_inode+0x2b1/0x460 fs/dcache.c:401
__dentry_kill+0x3c0/0x640 fs/dcache.c:607
dentry_kill fs/dcache.c:745 [inline]
dput+0x6ac/0xe10 fs/dcache.c:913
ovl_entry_stack_free fs/overlayfs/super.c:62 [inline]
ovl_dentry_release+0xce/0x140 fs/overlayfs/super.c:75
__dentry_kill+0x42b/0x640 fs/dcache.c:612
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

-> #1 (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
ext4_fname_setup_filename+0x8c/0x110 fs/ext4/crypto.c:28
ext4_find_entry+0x8c/0x140 fs/ext4/namei.c:1725
ext4_rename+0x51d/0x26d0 fs/ext4/namei.c:3829
ext4_rename2+0x1c7/0x270 fs/ext4/namei.c:4193
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 (fscrypt_init_mutex){+.+.}-{3:3}:
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
__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+0x19ff/0x26d0 fs/ext4/namei.c:3911
ext4_rename2+0x1c7/0x270 fs/ext4/namei.c:4193
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

other info that might help us debug this:

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

Possible unsafe locking scenario:

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

*** DEADLOCK ***

6 locks held by syz-executor.3/10194:
#0: ffff888044f80460 (sb_writers#4){.+.+}-{0:0}, at: do_renameat2+0x37f/0xc90 fs/namei.c:4859
#1: ffff888044f80748 (&type->s_vfs_rename_key){+.+.}-{3:3}, at: lock_rename+0x58/0x280 fs/namei.c:2995
#2: ffff888027b17258 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline]
#2: ffff888027b17258 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: lock_rename+0xa4/0x280 fs/namei.c:2999
#3: ffff88801caa0400 (&type->i_mutex_dir_key#3/2){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline]
#3: ffff88801caa0400 (&type->i_mutex_dir_key#3/2){+.+.}-{3:3}, at: lock_rename+0xd8/0x280 fs/namei.c:3000
#4: ffff888028c35440 (&sb->s_type->i_mutex_key#8/4){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:793 [inline]
#4: ffff888028c35440 (&sb->s_type->i_mutex_key#8/4){+.+.}-{3:3}, at: lock_two_nondirectories+0xd5/0x110 fs/inode.c:1124
#5: ffff888044f84990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xfb4/0x14e0 fs/jbd2/transaction.c:461

stack backtrace:
CPU: 1 PID: 10194 Comm: syz-executor.3 Not tainted 6.2.0-syzkaller-12998-gc0927a7a5391 #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
__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+0x19ff/0x26d0 fs/ext4/namei.c:3911
ext4_rename2+0x1c7/0x270 fs/ext4/namei.c:4193
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
RIP: 0023:0xf7f22579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f7f1d5cc EFLAGS: 00000296 ORIG_RAX: 0000000000000161
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00000000200001c0
RDX: 0000000000000004 RSI: 0000000020000200 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
----------------
Code disassembly (best guess), 2 bytes skipped:
0: 10 06 adc %al,(%rsi)
2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi
6: 10 07 adc %al,(%rdi)
8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi
c: 10 08 adc %cl,(%rax)
e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi
1e: 00 51 52 add %dl,0x52(%rcx)
21: 55 push %rbp
22: 89 e5 mov %esp,%ebp
24: 0f 34 sysenter
26: cd 80 int $0x80
* 28: 5d pop %rbp <-- trapping instruction
29: 5a pop %rdx
2a: 59 pop %rcx
2b: c3 retq
2c: 90 nop
2d: 90 nop
2e: 90 nop
2f: 90 nop
30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi
37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi

---
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Next message: Florian Westphal: "Re: [PATCH] [NETFILTER]: Keep conntrack reference until IPsecv6 policy checks are done"
Previous message: Jinlong Mao: "Re: [PATCH] coresight: core: Add sysfs node to reset all sources and sinks"
Next in thread: Eric Biggers: "Re: [syzbot] [fscrypt?] possible deadlock in fscrypt_initialize (2)"
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