======================================================
WARNING: possible circular locking dependency detected
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz-executor/5592 is trying to acquire lock:
ffff8880609fd8d0 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108

but task is already holding lock:
ffff8880618a5950 (&(log)->loglock){+.+.}-{4:4}, at: jfs_umount+0x17f/0x3d0 fs/jfs/jfs_umount.c:66

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&(log)->loglock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/rtmutex_api.c:534 [inline]
       mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:553
       lmLog+0x78/0xa30 fs/jfs/jfs_logmgr.c:234
       diLog fs/jfs/jfs_txnmgr.c:1454 [inline]
       txLog fs/jfs/jfs_txnmgr.c:1406 [inline]
       txCommit+0x16fb/0x5410 fs/jfs/jfs_txnmgr.c:1266
       jfs_commit_inode+0x2ef/0x530 fs/jfs/inode.c:114
       jfs_write_inode+0x145/0x220 fs/jfs/inode.c:138
       write_inode fs/fs-writeback.c:1584 [inline]
       __writeback_single_inode+0x75d/0x10e0 fs/fs-writeback.c:1827
       writeback_sb_inodes+0x97f/0x1980 fs/fs-writeback.c:2056
       wb_writeback+0x445/0xb00 fs/fs-writeback.c:2241
       wb_do_writeback fs/fs-writeback.c:2388 [inline]
       wb_workfn+0x3fd/0xf20 fs/fs-writeback.c:2428
       process_one_work kernel/workqueue.c:3302 [inline]
       process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
       worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
       kthread+0x388/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #0 (&jfs_ip->commit_mutex){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain kernel/locking/lockdep.c:3908 [inline]
       __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
       lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
       __mutex_lock_common kernel/locking/rtmutex_api.c:534 [inline]
       mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:553
       jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108
       jfs_write_inode+0x145/0x220 fs/jfs/inode.c:138
       write_inode fs/fs-writeback.c:1584 [inline]
       __writeback_single_inode+0x75d/0x10e0 fs/fs-writeback.c:1827
       writeback_single_inode+0x488/0xd60 fs/fs-writeback.c:1883
       write_inode_now+0x1c2/0x290 fs/fs-writeback.c:2974
       iput_final fs/inode.c:1950 [inline]
       iput+0x8c1/0xe80 fs/inode.c:2009
       jfs_umount+0x198/0x3d0 fs/jfs/jfs_umount.c:72
       jfs_put_super+0x8c/0x190 fs/jfs/super.c:194
       generic_shutdown_super+0x13d/0x2d0 fs/super.c:646
       kill_block_super+0x44/0x90 fs/super.c:1725
       deactivate_locked_super+0xbc/0x130 fs/super.c:476
       cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
       task_work_run+0x1d9/0x270 kernel/task_work.c:233
       resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
       __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
       exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
       __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
       syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
       syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
       do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&(log)->loglock);
                               lock(&jfs_ip->commit_mutex);
                               lock(&(log)->loglock);
  lock(&jfs_ip->commit_mutex);

 *** DEADLOCK ***

2 locks held by syz-executor/5592:
 #0: ffff8880626d80d0 (&type->s_umount_key#58){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff8880626d80d0 (&type->s_umount_key#58){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff8880626d80d0 (&type->s_umount_key#58){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508
 #1: ffff8880618a5950 (&(log)->loglock){+.+.}-{4:4}, at: jfs_umount+0x17f/0x3d0 fs/jfs/jfs_umount.c:66

stack backtrace:
CPU: 0 UID: 0 PID: 5592 Comm: syz-executor Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043
 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3165 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
 __mutex_lock_common kernel/locking/rtmutex_api.c:534 [inline]
 mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:553
 jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108
 jfs_write_inode+0x145/0x220 fs/jfs/inode.c:138
 write_inode fs/fs-writeback.c:1584 [inline]
 __writeback_single_inode+0x75d/0x10e0 fs/fs-writeback.c:1827
 writeback_single_inode+0x488/0xd60 fs/fs-writeback.c:1883
 write_inode_now+0x1c2/0x290 fs/fs-writeback.c:2974
 iput_final fs/inode.c:1950 [inline]
 iput+0x8c1/0xe80 fs/inode.c:2009
 jfs_umount+0x198/0x3d0 fs/jfs/jfs_umount.c:72
 jfs_put_super+0x8c/0x190 fs/jfs/super.c:194
 generic_shutdown_super+0x13d/0x2d0 fs/super.c:646
 kill_block_super+0x44/0x90 fs/super.c:1725
 deactivate_locked_super+0xbc/0x130 fs/super.c:476
 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5634b7e017
Code: a2 c7 05 dc 06 25 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffe8a5f2878 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f5634c12120 RCX: 00007f5634b7e017
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe8a5f2930
RBP: 00007ffe8a5f2930 R08: 00007ffe8a5f3930 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe8a5f39c0
R13: 00007f5634c12120 R14: 0000000000023955 R15: 00007ffe8a5f3a00
 </TASK>
Oops: general protection fault, probably for non-canonical address 0xdffffc000000015b: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000ad8-0x0000000000000adf]
CPU: 0 UID: 0 PID: 5592 Comm: syz-executor Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline]
RIP: 0010:do_raw_spin_lock+0x73/0x2f0 kernel/locking/spinlock_debug.c:115
Code: c7 44 24 30 30 f6 a0 81 4c 8d 64 24 20 49 c1 ec 03 48 b8 f1 f1 f1 f1 f8 f3 f3 f3 49 89 04 14 4c 8d 77 04 4c 89 f0 48 c1 e8 03 <0f> b6 04 10 84 c0 0f 85 f3 01 00 00 41 8b 06 3d ad 4e ad de 0f 85
RSP: 0018:ffffc90004417260 EFLAGS: 00010003
RAX: 000000000000015b RBX: 0000000000000ad8 RCX: 0000000080000003
RDX: dffffc0000000000 RSI: ffffffff8ba74c40 RDI: 0000000000000ad8
RBP: ffffc90004417320 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f11a5f R12: 1ffff92000882e50
R13: ffffc90004417420 R14: 0000000000000adc R15: 0000000000000ad8
FS:  0000555572f20500(0000) GS:ffff88812617c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa407883000 CR3: 0000000031e3e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 class_raw_spinlock_constructor include/linux/spinlock.h:535 [inline]
 remove_waiter+0x138/0xb10 kernel/locking/rtmutex.c:1561
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1751 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1779 [inline]
 rt_mutex_slowlock+0x72d/0x780 kernel/locking/rtmutex.c:1819
 __rt_mutex_lock kernel/locking/rtmutex.c:1834 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:535 [inline]
 mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:553
 lmLog+0x78/0xa30 fs/jfs/jfs_logmgr.c:234
 diLog fs/jfs/jfs_txnmgr.c:1454 [inline]
 txLog fs/jfs/jfs_txnmgr.c:1406 [inline]
 txCommit+0x16fb/0x5410 fs/jfs/jfs_txnmgr.c:1266
 jfs_commit_inode+0x2ef/0x530 fs/jfs/inode.c:114
 jfs_write_inode+0x145/0x220 fs/jfs/inode.c:138
 write_inode fs/fs-writeback.c:1584 [inline]
 __writeback_single_inode+0x75d/0x10e0 fs/fs-writeback.c:1827
 writeback_single_inode+0x488/0xd60 fs/fs-writeback.c:1883
 write_inode_now+0x1c2/0x290 fs/fs-writeback.c:2974
 iput_final fs/inode.c:1950 [inline]
 iput+0x8c1/0xe80 fs/inode.c:2009
 jfs_umount+0x198/0x3d0 fs/jfs/jfs_umount.c:72
 jfs_put_super+0x8c/0x190 fs/jfs/super.c:194
 generic_shutdown_super+0x13d/0x2d0 fs/super.c:646
 kill_block_super+0x44/0x90 fs/super.c:1725
 deactivate_locked_super+0xbc/0x130 fs/super.c:476
 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5634b7e017
Code: a2 c7 05 dc 06 25 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffe8a5f2878 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f5634c12120 RCX: 00007f5634b7e017
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe8a5f2930
RBP: 00007ffe8a5f2930 R08: 00007ffe8a5f3930 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe8a5f39c0
R13: 00007f5634c12120 R14: 0000000000023955 R15: 00007ffe8a5f3a00
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline]
RIP: 0010:do_raw_spin_lock+0x73/0x2f0 kernel/locking/spinlock_debug.c:115
Code: c7 44 24 30 30 f6 a0 81 4c 8d 64 24 20 49 c1 ec 03 48 b8 f1 f1 f1 f1 f8 f3 f3 f3 49 89 04 14 4c 8d 77 04 4c 89 f0 48 c1 e8 03 <0f> b6 04 10 84 c0 0f 85 f3 01 00 00 41 8b 06 3d ad 4e ad de 0f 85
RSP: 0018:ffffc90004417260 EFLAGS: 00010003
RAX: 000000000000015b RBX: 0000000000000ad8 RCX: 0000000080000003
RDX: dffffc0000000000 RSI: ffffffff8ba74c40 RDI: 0000000000000ad8
RBP: ffffc90004417320 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f11a5f R12: 1ffff92000882e50
R13: ffffc90004417420 R14: 0000000000000adc R15: 0000000000000ad8
FS:  0000555572f20500(0000) GS:ffff88812617c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa407883000 CR3: 0000000031e3e000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	c7 44 24 30 30 f6 a0 	movl   $0x81a0f630,0x30(%rsp)
   7:	81
   8:	4c 8d 64 24 20       	lea    0x20(%rsp),%r12
   d:	49 c1 ec 03          	shr    $0x3,%r12
  11:	48 b8 f1 f1 f1 f1 f8 	movabs $0xf3f3f3f8f1f1f1f1,%rax
  18:	f3 f3 f3
  1b:	49 89 04 14          	mov    %rax,(%r12,%rdx,1)
  1f:	4c 8d 77 04          	lea    0x4(%rdi),%r14
  23:	4c 89 f0             	mov    %r14,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	0f b6 04 10          	movzbl (%rax,%rdx,1),%eax <-- trapping instruction
  2e:	84 c0                	test   %al,%al
  30:	0f 85 f3 01 00 00    	jne    0x229
  36:	41 8b 06             	mov    (%r14),%eax
  39:	3d ad 4e ad de       	cmp    $0xdead4ead,%eax
  3e:	0f                   	.byte 0xf
  3f:	85                   	.byte 0x85