warning: checkpointing journal with EXT4_IOC_CHECKPOINT_FLAG_ZEROOUT can be slow
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.0/4406 is trying to acquire lock:
ffff0000d4f4c170 (&journal->j_barrier){+.+.}-{3:3}, at: jbd2_journal_lock_updates+0x260/0x318 fs/jbd2/transaction.c:905

but task is already holding lock:
ffff0000d4f48c58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_change_inode_journal_flag+0x150/0x630 fs/ext4/inode.c:6124

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&sbi->s_writepages_rwsem){++++}-{0:0}:
       percpu_down_write+0xcc/0x39c kernel/locking/percpu-rwsem.c:217
       ext4_change_inode_journal_flag+0x150/0x630 fs/ext4/inode.c:6124
       ext4_ioctl_setflags fs/ext4/ioctl.c:448 [inline]
       ext4_fileattr_set+0xbd8/0x133c fs/ext4/ioctl.c:766
       vfs_fileattr_set+0x67c/0x90c fs/ioctl.c:700
       ioctl_setflags fs/ioctl.c:732 [inline]
       do_vfs_ioctl+0x1c88/0x23f0 fs/ioctl.c:843
       __do_sys_ioctl fs/ioctl.c:872 [inline]
       __se_sys_ioctl fs/ioctl.c:860 [inline]
       __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:860
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:181
       el0_svc+0x78/0x1d0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #3 (mapping.invalidate_lock){++++}-{3:3}:
       down_write+0xbc/0x12c kernel/locking/rwsem.c:1551
       filemap_invalidate_lock include/linux/fs.h:832 [inline]
       ext4_setattr+0xb30/0x1518 fs/ext4/inode.c:5543
       notify_change+0xa08/0xcd8 fs/attr.c:505
       do_truncate+0x188/0x20c fs/open.c:65
       do_sys_ftruncate+0x284/0x31c fs/open.c:193
       __do_sys_ftruncate fs/open.c:204 [inline]
       __se_sys_ftruncate fs/open.c:202 [inline]
       __arm64_sys_ftruncate+0x60/0x74 fs/open.c:202
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:181
       el0_svc+0x78/0x1d0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #2 (&sb->s_type->i_mutex_key#9){++++}-{3:3}:
       down_read+0xc0/0x38c kernel/locking/rwsem.c:1498
       inode_lock_shared include/linux/fs.h:797 [inline]
       ext4_bmap+0x54/0x360 fs/ext4/inode.c:3166
       bmap+0xa8/0xe8 fs/inode.c:1820
       jbd2_journal_bmap fs/jbd2/journal.c:981 [inline]
       __jbd2_journal_erase fs/jbd2/journal.c:1795 [inline]
       jbd2_journal_flush+0x600/0xa28 fs/jbd2/journal.c:2515
       ext4_ioctl_checkpoint fs/ext4/ioctl.c:850 [inline]
       __ext4_ioctl fs/ext4/ioctl.c:1276 [inline]
       ext4_ioctl+0x2e0c/0x3750 fs/ext4/ioctl.c:1285
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl fs/ioctl.c:860 [inline]
       __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:181
       el0_svc+0x78/0x1d0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #1 (&journal->j_checkpoint_mutex){+.+.}-{3:3}:
       __mutex_lock_common+0x194/0x1f14 kernel/locking/mutex.c:596
       mutex_lock_io_nested+0xcc/0x12c kernel/locking/mutex.c:777
       jbd2_journal_flush+0x1e8/0xa28 fs/jbd2/journal.c:2487
       ext4_ioctl_checkpoint fs/ext4/ioctl.c:850 [inline]
       __ext4_ioctl fs/ext4/ioctl.c:1276 [inline]
       ext4_ioctl+0x2e0c/0x3750 fs/ext4/ioctl.c:1285
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl fs/ioctl.c:860 [inline]
       __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:181
       el0_svc+0x78/0x1d0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #0 (&journal->j_barrier){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x2870/0x67ec kernel/locking/lockdep.c:5012
       lock_acquire+0x1f4/0x618 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x194/0x1f14 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0xac/0x11c kernel/locking/mutex.c:743
       jbd2_journal_lock_updates+0x260/0x318 fs/jbd2/transaction.c:905
       ext4_change_inode_journal_flag+0x158/0x630 fs/ext4/inode.c:6125
       ext4_ioctl_setflags fs/ext4/ioctl.c:448 [inline]
       ext4_fileattr_set+0xbd8/0x133c fs/ext4/ioctl.c:766
       vfs_fileattr_set+0x67c/0x90c fs/ioctl.c:700
       ioctl_setflags fs/ioctl.c:732 [inline]
       do_vfs_ioctl+0x1c88/0x23f0 fs/ioctl.c:843
       __do_sys_ioctl fs/ioctl.c:872 [inline]
       __se_sys_ioctl fs/ioctl.c:860 [inline]
       __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:860
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b0 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:181
       el0_svc+0x78/0x1d0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

other info that might help us debug this:

Chain exists of:
  &journal->j_barrier --> mapping.invalidate_lock --> &sbi->s_writepages_rwsem

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&sbi->s_writepages_rwsem);
                               lock(mapping.invalidate_lock);
                               lock(&sbi->s_writepages_rwsem);
  lock(&journal->j_barrier);

 *** DEADLOCK ***

4 locks held by syz-executor.0/4406:
 #0: ffff0000d4f46460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write_file+0x64/0x1e8 fs/namespace.c:430
 #1: ffff0000df7949b8 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff0000df7949b8 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: vfs_fileattr_set+0x110/0x90c fs/ioctl.c:685
 #2: ffff0000df794b58 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #2: ffff0000df794b58 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_change_inode_journal_flag+0xf0/0x630 fs/ext4/inode.c:6116
 #3: ffff0000d4f48c58 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_change_inode_journal_flag+0x150/0x630 fs/ext4/inode.c:6124

stack backtrace:
CPU: 0 PID: 4406 Comm: syz-executor.0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call trace:
 dump_backtrace+0x0/0x458 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 dump_stack+0x1c/0x5c lib/dump_stack.c:113
 print_circular_bug+0x148/0x1b0 kernel/locking/lockdep.c:2011
 check_noncircular+0x264/0x2f8 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x2870/0x67ec kernel/locking/lockdep.c:5012
 lock_acquire+0x1f4/0x618 kernel/locking/lockdep.c:5623
 __mutex_lock_common+0x194/0x1f14 kernel/locking/mutex.c:596
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0xac/0x11c kernel/locking/mutex.c:743
 jbd2_journal_lock_updates+0x260/0x318 fs/jbd2/transaction.c:905
 ext4_change_inode_journal_flag+0x158/0x630 fs/ext4/inode.c:6125
 ext4_ioctl_setflags fs/ext4/ioctl.c:448 [inline]
 ext4_fileattr_set+0xbd8/0x133c fs/ext4/ioctl.c:766
 vfs_fileattr_set+0x67c/0x90c fs/ioctl.c:700
 ioctl_setflags fs/ioctl.c:732 [inline]
 do_vfs_ioctl+0x1c88/0x23f0 fs/ioctl.c:843
 __do_sys_ioctl fs/ioctl.c:872 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:860
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b0 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:181
 el0_svc+0x78/0x1d0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584