[v6.1] possible deadlock in ext4_ioctl

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ca87e77a2ef8 Linux 6.1.34
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=157b95f3280000
kernel config: https://syzkaller.appspot.com/x/.config?x=c188e92022a334b
dashboard link: https://syzkaller.appspot.com/bug?extid=b430ca05e157e7bc3202
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f48d514c343c/disk-ca87e77a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/563336f1f216/vmlinux-ca87e77a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2254afa3642b/bzImage-ca87e77a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b430ca...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.1.34-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.3/11688 is trying to acquire lock:
ffff888089faf0e0 (&ei->i_data_sem/1){+.+.}-{3:3}, at: swap_inode_boot_loader fs/ext4/ioctl.c:426 [inline]
ffff888089faf0e0 (&ei->i_data_sem/1){+.+.}-{3:3}, at: __ext4_ioctl fs/ext4/ioctl.c:1421 [inline]
ffff888089faf0e0 (&ei->i_data_sem/1){+.+.}-{3:3}, at: ext4_ioctl+0x462a/0x5f70 fs/ext4/ioctl.c:1611

but task is already holding lock:
ffff888089fa9698 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_double_down_write_data_sem+0x28/0x40

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&ei->i_data_sem/2){++++}-{3:3}:
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
down_read+0x43/0x2e0 kernel/locking/rwsem.c:1520
ext4_map_blocks+0x38a/0x1ce0 fs/ext4/inode.c:574
ext4_getblk+0x1eb/0x7c0 fs/ext4/inode.c:864
ext4_bread+0x2a/0x170 fs/ext4/inode.c:920
ext4_quota_write+0x21e/0x570 fs/ext4/super.c:7132
write_blk fs/quota/quota_tree.c:64 [inline]
get_free_dqblk+0x340/0x6c0 fs/quota/quota_tree.c:130
do_insert_tree+0x299/0x1ae0 fs/quota/quota_tree.c:340
do_insert_tree+0x72a/0x1ae0 fs/quota/quota_tree.c:375
dq_insert_tree fs/quota/quota_tree.c:401 [inline]
qtree_write_dquot+0x3b9/0x530 fs/quota/quota_tree.c:420
v2_write_dquot+0x11c/0x190 fs/quota/quota_v2.c:358
dquot_acquire+0x34d/0x680 fs/quota/dquot.c:444
ext4_acquire_dquot+0x2e6/0x400 fs/ext4/super.c:6766
dqget+0x98b/0xdb0 fs/quota/dquot.c:914
dquot_transfer+0x648/0x8a0 fs/quota/dquot.c:2117
ext4_setattr+0xbd3/0x1a00 fs/ext4/inode.c:5453
notify_change+0xdcd/0x1080 fs/attr.c:482
chown_common+0x5aa/0x900 fs/open.c:736
do_fchownat+0x169/0x240 fs/open.c:767
__do_sys_fchownat fs/open.c:782 [inline]
__se_sys_fchownat fs/open.c:779 [inline]
__x64_sys_fchownat+0xb1/0xc0 fs/open.c:779
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #2 (&s->s_dquot.dqio_sem){++++}-{3:3}:
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
down_read+0x43/0x2e0 kernel/locking/rwsem.c:1520
v2_read_dquot+0x4a/0x100 fs/quota/quota_v2.c:332
dquot_acquire+0x188/0x680 fs/quota/dquot.c:435
ext4_acquire_dquot+0x2e6/0x400 fs/ext4/super.c:6766
dqget+0x98b/0xdb0 fs/quota/dquot.c:914
__dquot_initialize+0x2d9/0xe10 fs/quota/dquot.c:1492
ext4_process_orphan+0x57/0x2d0 fs/ext4/orphan.c:329
ext4_orphan_cleanup+0xb70/0x1400 fs/ext4/orphan.c:474
__ext4_fill_super fs/ext4/super.c:5533 [inline]
ext4_fill_super+0x83cf/0x8b20 fs/ext4/super.c:5661
get_tree_bdev+0x3fe/0x620 fs/super.c:1346
vfs_get_tree+0x88/0x270 fs/super.c:1553
do_new_mount+0x28b/0xae0 fs/namespace.c:3040
do_mount fs/namespace.c:3383 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3568
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (&dquot->dq_lock){+.+.}-{3:3}:
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
__mutex_lock_common+0x1d4/0x2520 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
dquot_commit+0x57/0x510 fs/quota/dquot.c:479
ext4_write_dquot+0x1e8/0x2b0 fs/ext4/super.c:6750
mark_dquot_dirty fs/quota/dquot.c:346 [inline]
mark_all_dquot_dirty fs/quota/dquot.c:384 [inline]
__dquot_free_space+0x992/0xfa0 fs/quota/dquot.c:1907
dquot_free_space_nodirty include/linux/quotaops.h:379 [inline]
dquot_free_space include/linux/quotaops.h:384 [inline]
swap_inode_boot_loader fs/ext4/ioctl.c:492 [inline]
__ext4_ioctl fs/ext4/ioctl.c:1421 [inline]
ext4_ioctl+0x509a/0x5f70 fs/ext4/ioctl.c:1611
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&ei->i_data_sem/1){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3832
__lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
down_write_nested+0x39/0x60 kernel/locking/rwsem.c:1689
swap_inode_boot_loader fs/ext4/ioctl.c:426 [inline]
__ext4_ioctl fs/ext4/ioctl.c:1421 [inline]
ext4_ioctl+0x462a/0x5f70 fs/ext4/ioctl.c:1611
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
&ei->i_data_sem/1 --> &s->s_dquot.dqio_sem --> &ei->i_data_sem/2

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&ei->i_data_sem/2);
lock(&s->s_dquot.dqio_sem);
lock(&ei->i_data_sem/2);
lock(&ei->i_data_sem/1);

*** DEADLOCK ***

6 locks held by syz-executor.3/11688:
#0: ffff88814c038460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write_file+0x5a/0x1f0 fs/namespace.c:437
#1: ffff888089fa9810 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
#1: ffff888089fa9810 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: lock_two_nondirectories+0xde/0x130 fs/inode.c:1121
#2: ffff888089faf258 (&sb->s_type->i_mutex_key#8/4){+.+.}-{3:3}, at: swap_inode_boot_loader fs/ext4/ioctl.c:385 [inline]
#2: ffff888089faf258 (&sb->s_type->i_mutex_key#8/4){+.+.}-{3:3}, at: __ext4_ioctl fs/ext4/ioctl.c:1421 [inline]
#2: ffff888089faf258 (&sb->s_type->i_mutex_key#8/4){+.+.}-{3:3}, at: ext4_ioctl+0x262e/0x5f70 fs/ext4/ioctl.c:1611
#3: ffff888089fa99b0 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:801 [inline]
#3: ffff888089fa99b0 (mapping.invalidate_lock){++++}-{3:3}, at: swap_inode_boot_loader fs/ext4/ioctl.c:402 [inline]
#3: ffff888089fa99b0 (mapping.invalidate_lock){++++}-{3:3}, at: __ext4_ioctl fs/ext4/ioctl.c:1421 [inline]
#3: ffff888089fa99b0 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_ioctl+0x42f1/0x5f70 fs/ext4/ioctl.c:1611
#4: ffff88814c03c990 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x13c8/0x1640 fs/jbd2/transaction.c:461
#5: ffff888089fa9698 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_double_down_write_data_sem+0x28/0x40

stack backtrace:
CPU: 1 PID: 11688 Comm: syz-executor.3 Not tainted 6.1.34-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
check_noncircular+0x2fa/0x3b0 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+0x1667/0x58e0 kernel/locking/lockdep.c:3832
__lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
down_write_nested+0x39/0x60 kernel/locking/rwsem.c:1689
swap_inode_boot_loader fs/ext4/ioctl.c:426 [inline]
__ext4_ioctl fs/ext4/ioctl.c:1421 [inline]
ext4_ioctl+0x462a/0x5f70 fs/ext4/ioctl.c:1611
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f2dcc48c389
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2dcd185168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2dcc5abf80 RCX: 00007f2dcc48c389
RDX: 0000000000000000 RSI: 0000000000006611 RDI: 0000000000000005
RBP: 00007f2dcc4d7493 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc95f52f7f R14: 00007f2dcd185300 R15: 0000000000022000
</TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to change bug's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.