loop6: detected capacity change from 0 to 264192
======================================================
WARNING: possible circular locking dependency detected
6.2.0-next-20230223 #1 Not tainted
------------------------------------------------------
syz-executor.4/58772 is trying to acquire lock:
ffff88800c188400 (&sb->s_type->i_mutex_key#6){++++}-{3:3}, at: ext4_bmap+0x52/0x470

but task is already holding lock:
ffff88800fffc3f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: jbd2_journal_flush+0x483/0xc90

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&journal->j_checkpoint_mutex){+.+.}-{3:3}:
       mutex_lock_io_nested+0x149/0x1300
       __jbd2_log_wait_for_space+0x238/0x4b0
       add_transaction_credits+0xa42/0xb80
       start_this_handle+0x3a6/0x14d0
       jbd2__journal_start+0x394/0x6b0
       __ext4_journal_start_sb+0x4c2/0x6f0
       __ext4_unlink+0x44e/0xcf0
       ext4_unlink+0x3ac/0x640
       vfs_unlink+0x35e/0x930
       do_unlinkat+0x3b9/0x650
       __x64_sys_unlink+0xca/0x110
       do_syscall_64+0x3f/0x90
       entry_SYSCALL_64_after_hwframe+0x72/0xdc

-> #0 (&sb->s_type->i_mutex_key#6){++++}-{3:3}:
       __lock_acquire+0x2d56/0x6380
       lock_acquire.part.0+0xea/0x320
       down_read+0x3d/0x50
       ext4_bmap+0x52/0x470
       bmap+0xb0/0x130
       jbd2_journal_bmap+0xac/0x1d0
       jbd2_journal_flush+0x87f/0xc90
       __ext4_ioctl+0x9fd/0x4330
       __x64_sys_ioctl+0x19e/0x210
       do_syscall_64+0x3f/0x90
       entry_SYSCALL_64_after_hwframe+0x72/0xdc

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&journal->j_checkpoint_mutex);
                               lock(&sb->s_type->i_mutex_key#6);
                               lock(&journal->j_checkpoint_mutex);
  lock(&sb->s_type->i_mutex_key#6);

 *** DEADLOCK ***

2 locks held by syz-executor.4/58772:
 #0: ffff88800fffc170 (&journal->j_barrier){+.+.}-{3:3}, at: jbd2_journal_lock_updates+0x162/0x310
 #1: ffff88800fffc3f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: jbd2_journal_flush+0x483/0xc90

stack backtrace:
CPU: 1 PID: 58772 Comm: syz-executor.4 Not tainted 6.2.0-next-20230223 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x91/0xf0
 check_noncircular+0x263/0x2e0
 __lock_acquire+0x2d56/0x6380
 lock_acquire.part.0+0xea/0x320
 down_read+0x3d/0x50
 ext4_bmap+0x52/0x470
 bmap+0xb0/0x130
 jbd2_journal_bmap+0xac/0x1d0
 jbd2_journal_flush+0x87f/0xc90
 __ext4_ioctl+0x9fd/0x4330
 __x64_sys_ioctl+0x19e/0x210
 do_syscall_64+0x3f/0x90
 entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7f6f7c0cdb19
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6f79643188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f6f7c1e0f60 RCX: 00007f6f7c0cdb19
RDX: 0000000020000340 RSI: 000000004004662b RDI: 0000000000000004
RBP: 00007f6f7c127f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffcaf8c6b3f R14: 00007f6f79643300 R15: 0000000000022000
 </TASK>
EXT4-fs (loop6): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
ext4 filesystem being mounted at /syzkaller-testdir812686412/syzkaller.KOHKk0/1350/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs (loop6): unmounting filesystem 00000000-0000-0000-0000-000000000000.
loop6: detected capacity change from 0 to 264192
EXT4-fs (loop6): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
ext4 filesystem being mounted at /syzkaller-testdir812686412/syzkaller.KOHKk0/1351/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs (loop6): unmounting filesystem 00000000-0000-0000-0000-000000000000.
loop6: detected capacity change from 0 to 264192
EXT4-fs (loop6): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
ext4 filesystem being mounted at /syzkaller-testdir812686412/syzkaller.KOHKk0/1352/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs (loop6): unmounting filesystem 00000000-0000-0000-0000-000000000000.
loop6: detected capacity change from 0 to 264192
EXT4-fs (loop6): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
ext4 filesystem being mounted at /syzkaller-testdir812686412/syzkaller.KOHKk0/1353/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs (loop6): unmounting filesystem 00000000-0000-0000-0000-000000000000.
loop6: detected capacity change from 0 to 264192
EXT4-fs (loop6): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
ext4 filesystem being mounted at /syzkaller-testdir812686412/syzkaller.KOHKk0/1354/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs (loop6): unmounting filesystem 00000000-0000-0000-0000-000000000000.
loop6: detected capacity change from 0 to 264192
EXT4-fs (loop6): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
ext4 filesystem being mounted at /syzkaller-testdir812686412/syzkaller.KOHKk0/1355/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs (loop6): unmounting filesystem 00000000-0000-0000-0000-000000000000.
loop6: detected capacity change from 0 to 264192
EXT4-fs (loop6): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
ext4 filesystem being mounted at /syzkaller-testdir812686412/syzkaller.KOHKk0/1356/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs (loop6): unmounting filesystem 00000000-0000-0000-0000-000000000000.
loop6: detected capacity change from 0 to 264192
EXT4-fs (loop6): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
ext4 filesystem being mounted at /syzkaller-testdir812686412/syzkaller.KOHKk0/1357/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs (loop6): unmounting filesystem 00000000-0000-0000-0000-000000000000.
loop6: detected capacity change from 0 to 264192
EXT4-fs (loop6): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
ext4 filesystem being mounted at /syzkaller-testdir812686412/syzkaller.KOHKk0/1358/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs (loop6): unmounting filesystem 00000000-0000-0000-0000-000000000000.
loop6: detected capacity change from 0 to 264192
EXT4-fs (loop6): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
ext4 filesystem being mounted at /syzkaller-testdir812686412/syzkaller.KOHKk0/1359/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs (loop6): unmounting filesystem 00000000-0000-0000-0000-000000000000.
loop6: detected capacity change from 0 to 264192
EXT4-fs (loop6): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
ext4 filesystem being mounted at /syzkaller-testdir812686412/syzkaller.KOHKk0/1360/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs (loop6): unmounting filesystem 00000000-0000-0000-0000-000000000000.
loop6: detected capacity change from 0 to 264192
EXT4-fs (loop6): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
ext4 filesystem being mounted at /syzkaller-testdir812686412/syzkaller.KOHKk0/1361/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs (loop6): unmounting filesystem 00000000-0000-0000-0000-000000000000.
loop6: detected capacity change from 0 to 264192
EXT4-fs (loop6): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
ext4 filesystem being mounted at /syzkaller-testdir812686412/syzkaller.KOHKk0/1362/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs (loop6): unmounting filesystem 00000000-0000-0000-0000-000000000000.
loop6: detected capacity change from 0 to 264192
EXT4-fs (loop6): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
ext4 filesystem being mounted at /syzkaller-testdir812686412/syzkaller.KOHKk0/1363/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs (loop6): unmounting filesystem 00000000-0000-0000-0000-000000000000.
loop6: detected capacity change from 0 to 264192
EXT4-fs (loop6): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
ext4 filesystem being mounted at /syzkaller-testdir812686412/syzkaller.KOHKk0/1364/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs (loop6): unmounting filesystem 00000000-0000-0000-0000-000000000000.
loop6: detected capacity change from 0 to 264192
EXT4-fs (loop6): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
ext4 filesystem being mounted at /syzkaller-testdir812686412/syzkaller.KOHKk0/1365/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs (loop6): unmounting filesystem 00000000-0000-0000-0000-000000000000.
loop6: detected capacity change from 0 to 264192
EXT4-fs (loop6): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback.
ext4 filesystem being mounted at /syzkaller-testdir812686412/syzkaller.KOHKk0/1366/file0 supports timestamps until 2038 (0x7fffffff)
EXT4-fs (loop6): unmounting filesystem 00000000-0000-0000-0000-000000000000.