Scheduler tracepoints stat_sleep, stat_iowait, stat_blocked and stat_runtime require the kernel parameter schedstats=enable or kernel.sched_schedstats=1 ====================================================== WARNING: possible circular locking dependency detected 6.1.15-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.5/11629 is trying to acquire lock: ffff888140ee0400 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:766 [inline] ffff888140ee0400 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_bmap+0x4b/0x410 fs/ext4/inode.c:3171 but task is already holding lock: ffff8880295f23f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: jbd2_journal_flush+0x323/0xc40 fs/jbd2/journal.c:2474 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&journal->j_checkpoint_mutex){+.+.}-{3:3}: lock_acquire+0x231/0x620 kernel/locking/lockdep.c:5668 __mutex_lock_common+0x1d4/0x2520 kernel/locking/mutex.c:603 mutex_lock_io_nested+0x43/0x60 kernel/locking/mutex.c:833 __jbd2_log_wait_for_space+0x213/0x760 fs/jbd2/checkpoint.c:110 add_transaction_credits+0x94c/0xc00 fs/jbd2/transaction.c:298 start_this_handle+0x747/0x1640 fs/jbd2/transaction.c:422 jbd2__journal_start+0x2d1/0x5c0 fs/jbd2/transaction.c:520 __ext4_journal_start_sb+0x206/0x4e0 fs/ext4/ext4_jbd2.c:105 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline] ext4_dirty_inode+0x8b/0x100 fs/ext4/inode.c:6037 __mark_inode_dirty+0x3d9/0x1220 fs/fs-writeback.c:2408 mark_inode_dirty include/linux/fs.h:2481 [inline] generic_write_end+0x180/0x1d0 fs/buffer.c:2184 ext4_da_write_end+0x836/0xba0 fs/ext4/inode.c:3103 generic_perform_write+0x3e9/0x5e0 mm/filemap.c:3765 ext4_buffered_write_iter+0x122/0x3a0 fs/ext4/file.c:285 ext4_file_write_iter+0x1d2/0x18f0 call_write_iter include/linux/fs.h:2205 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x7ae/0xba0 fs/read_write.c:584 ksys_write+0x19c/0x2c0 fs/read_write.c:637 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 (&sb->s_type->i_mutex_key#8){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3831 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5055 lock_acquire+0x231/0x620 kernel/locking/lockdep.c:5668 down_read+0x39/0x50 kernel/locking/rwsem.c:1509 inode_lock_shared include/linux/fs.h:766 [inline] ext4_bmap+0x4b/0x410 fs/ext4/inode.c:3171 bmap+0xa1/0xd0 fs/inode.c:1798 jbd2_journal_bmap fs/jbd2/journal.c:977 [inline] __jbd2_journal_erase fs/jbd2/journal.c:1789 [inline] jbd2_journal_flush+0x5b5/0xc40 fs/jbd2/journal.c:2492 ext4_ioctl_checkpoint fs/ext4/ioctl.c:1082 [inline] __ext4_ioctl fs/ext4/ioctl.c:1590 [inline] ext4_ioctl+0x3a7d/0x61c0 fs/ext4/ioctl.c:1610 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: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&journal->j_checkpoint_mutex); lock(&sb->s_type->i_mutex_key#8); lock(&journal->j_checkpoint_mutex); lock(&sb->s_type->i_mutex_key#8); *** DEADLOCK *** 2 locks held by syz-executor.5/11629: #0: ffff8880295f2170 (&journal->j_barrier){+.+.}-{3:3}, at: jbd2_journal_lock_updates+0x2a8/0x370 fs/jbd2/transaction.c:904 #1: ffff8880295f23f8 (&journal->j_checkpoint_mutex){+.+.}-{3:3}, at: jbd2_journal_flush+0x323/0xc40 fs/jbd2/journal.c:2474 stack backtrace: CPU: 0 PID: 11629 Comm: syz-executor.5 Not tainted 6.1.15-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 Call Trace: __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:2177 check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain+0x1667/0x58e0 kernel/locking/lockdep.c:3831 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5055 lock_acquire+0x231/0x620 kernel/locking/lockdep.c:5668 down_read+0x39/0x50 kernel/locking/rwsem.c:1509 inode_lock_shared include/linux/fs.h:766 [inline] ext4_bmap+0x4b/0x410 fs/ext4/inode.c:3171 bmap+0xa1/0xd0 fs/inode.c:1798 jbd2_journal_bmap fs/jbd2/journal.c:977 [inline] __jbd2_journal_erase fs/jbd2/journal.c:1789 [inline] jbd2_journal_flush+0x5b5/0xc40 fs/jbd2/journal.c:2492 ext4_ioctl_checkpoint fs/ext4/ioctl.c:1082 [inline] __ext4_ioctl fs/ext4/ioctl.c:1590 [inline] ext4_ioctl+0x3a7d/0x61c0 fs/ext4/ioctl.c:1610 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: 0033:0x7f3f0408c0f9 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:00007f3f04e8a168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f3f041abf80 RCX: 00007f3f0408c0f9 RDX: 00000000200005c0 RSI: 000000004004662b RDI: 0000000000000005 RBP: 00007f3f040e7ae9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc4eb5c6df R14: 00007f3f04e8a300 R15: 0000000000022000