======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
ksoftirqd/0/15 is trying to acquire lock:
ffff888112c1f9e8 (&(log)->gclock){..-.}-{3:3}, at: lmPostGC fs/jfs/jfs_logmgr.c:810 [inline]
ffff888112c1f9e8 (&(log)->gclock){..-.}-{3:3}, at: lbmIODone+0x681/0x17b0 fs/jfs/jfs_logmgr.c:2284

but task is already holding lock:
ffffffff8e396158 (jfsLCacheLock){..-.}-{3:3}, at: lbmIODone+0x92/0x17b0 fs/jfs/jfs_logmgr.c:2181

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (jfsLCacheLock){..-.}-{3:3}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
       lbmWrite+0x115/0x490 fs/jfs/jfs_logmgr.c:2022
       lmGCwrite fs/jfs/jfs_logmgr.c:-1 [inline]
       lmGroupCommit+0x570/0xb30 fs/jfs/jfs_logmgr.c:687
       txCommit+0x4940/0x5430 fs/jfs/jfs_txnmgr.c:1305
       diNewIAG fs/jfs/jfs_imap.c:2592 [inline]
       diAllocExt fs/jfs/jfs_imap.c:1905 [inline]
       diAllocAG+0x1770/0x1df0 fs/jfs/jfs_imap.c:1669
       diAlloc+0x1d5/0x1680 fs/jfs/jfs_imap.c:1590
       ialloc+0x8c/0x8f0 fs/jfs/jfs_inode.c:56
       jfs_mkdir+0x193/0xa70 fs/jfs/namei.c:225
       vfs_mkdir+0x512/0x5b0 fs/namei.c:5130
       do_mkdirat+0x276/0x4b0 fs/namei.c:5164
       __do_sys_mkdirat fs/namei.c:5186 [inline]
       __se_sys_mkdirat fs/namei.c:5184 [inline]
       __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:5184
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&(log)->gclock){..-.}-{3:3}:
       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+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
       lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
       lmPostGC fs/jfs/jfs_logmgr.c:810 [inline]
       lbmIODone+0x681/0x17b0 fs/jfs/jfs_logmgr.c:2284
       blk_update_request+0x57e/0xe60 block/blk-mq.c:1007
       blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1169
       blk_complete_reqs block/blk-mq.c:1244 [inline]
       blk_done_softirq+0x10a/0x160 block/blk-mq.c:1249
       handle_softirqs+0x27d/0x850 kernel/softirq.c:622
       run_ksoftirqd+0x9b/0x100 kernel/softirq.c:1063
       smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
       kthread+0x711/0x8a0 kernel/kthread.c:463
       ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(jfsLCacheLock);
                               lock(&(log)->gclock);
                               lock(jfsLCacheLock);
  lock(&(log)->gclock);

 *** DEADLOCK ***

1 lock held by ksoftirqd/0/15:
 #0: ffffffff8e396158 (jfsLCacheLock){..-.}-{3:3}, at: lbmIODone+0x92/0x17b0 fs/jfs/jfs_logmgr.c:2181

stack backtrace:
CPU: 0 UID: 0 PID: 15 Comm: ksoftirqd/0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_circular_bug+0x2e2/0x300 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+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
 lmPostGC fs/jfs/jfs_logmgr.c:810 [inline]
 lbmIODone+0x681/0x17b0 fs/jfs/jfs_logmgr.c:2284
 blk_update_request+0x57e/0xe60 block/blk-mq.c:1007
 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1169
 blk_complete_reqs block/blk-mq.c:1244 [inline]
 blk_done_softirq+0x10a/0x160 block/blk-mq.c:1249
 handle_softirqs+0x27d/0x850 kernel/softirq.c:622
 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:1063
 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>