reiserfs locking (v2)

[Sergey Senozhatsky]

Code with munmap produces:

[   54.152356] 
[   54.152358] =======================================================
[   54.152363] [ INFO: possible circular locking dependency detected ] 
[   54.152367] 2.6.35-rc3-dbg-git6-00502-g94feaba-dirty #65
[   54.152371] -------------------------------------------------------
[   54.152374] a.out/4044 is trying to acquire lock:                  
[   54.152378]  (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<c10f1d4e>] reiserfs_file_release+0x11d/0x344
[   54.152394]                   
[   54.152395] but task is already holding lock:
[   54.152398]  (&mm->mmap_sem){++++++}, at: [<c1091b7f>] sys_munmap+0x26/0x42
[   54.152408] 
[   54.152409] which lock already depends on the new lock.
[   54.152410] 
[   54.152413] 
[   54.152414] the existing dependency chain (in reverse order) is:
[   54.152417] 
[   54.152418] -> #1 (&mm->mmap_sem){++++++}:
[   54.152425]        [<c104f566>] lock_acquire+0x59/0x70
[   54.152433]        [<c108cf70>] might_fault+0x53/0x70
[   54.152439]        [<c1185418>] copy_to_user+0x30/0x48    
[   54.152445]        [<c10afaf9>] filldir64+0x95/0xc9
[   54.152451]        [<c10f255c>] reiserfs_readdir_dentry+0x35d/0x4d9
[   54.152457]        [<c10f26ea>] reiserfs_readdir+0x12/0x17         
[   54.152463]        [<c10afd17>] vfs_readdir+0x6d/0x92     
[   54.152468]        [<c10afe91>] sys_getdents64+0x63/0xa2  
[   54.152473]        [<c10027d3>] sysenter_do_call+0x12/0x32
[   54.152480] 
[   54.152481] -> #0 (&sb->s_type->i_mutex_key#10){+.+.+.}:   
[   54.152488]        [<c104ef5c>] __lock_acquire+0x96d/0xbe1
[   54.152494]        [<c104f566>] lock_acquire+0x59/0x70    
[   54.152500]        [<c12c5674>] __mutex_lock_common+0x39/0x36b
[   54.152507]        [<c12c59e0>] mutex_lock_nested+0x12/0x15   
[   54.152512]        [<c10f1d4e>] reiserfs_file_release+0x11d/0x344
[   54.152518]        [<c10a5805>] fput+0xe0/0x16a
[   54.152524]        [<c1090c9e>] remove_vma+0x28/0x47
[   54.152529]        [<c1091a60>] do_munmap+0x1e8/0x200
[   54.152535]        [<c1091b8b>] sys_munmap+0x32/0x42 
[   54.152540]        [<c10027d3>] sysenter_do_call+0x12/0x32
[   54.152546] 
[   54.152546] other info that might help us debug this:
[   54.152548]                                          
[   54.152552] 1 lock held by a.out/4044:
[   54.152554]  #0:  (&mm->mmap_sem){++++++}, at: [<c1091b7f>] sys_munmap+0x26/0x42
[   54.152563] 
[   54.152564] stack backtrace:
[   54.152569] Pid: 4044, comm: a.out Not tainted 2.6.35-rc3-dbg-git6-00502-g94feaba-dirty #65
[   54.152572] Call Trace:                  
[   54.152577]  [<c12c48f3>] ? printk+0xf/0x11
[   54.152583]  [<c104dc09>] print_circular_bug+0x8a/0x96
[   54.152589]  [<c104ef5c>] __lock_acquire+0x96d/0xbe1
[   54.152595]  [<c104e462>] ? mark_lock+0x26/0x1b3    
[   54.152601]  [<c104f566>] lock_acquire+0x59/0x70
[   54.152607]  [<c10f1d4e>] ? reiserfs_file_release+0x11d/0x344
[   54.152612]  [<c12c5674>] __mutex_lock_common+0x39/0x36b     
[   54.152618]  [<c10f1d4e>] ? reiserfs_file_release+0x11d/0x344
[   54.152624]  [<c12c59e0>] mutex_lock_nested+0x12/0x15        
[   54.152629]  [<c10f1d4e>] ? reiserfs_file_release+0x11d/0x344
[   54.152634]  [<c10f1d4e>] reiserfs_file_release+0x11d/0x344  
[   54.152640]  [<c108d77d>] ? free_pgd_range+0x96/0x12f
[   54.152646]  [<c10a57b5>] ? fput+0x90/0x16a
[   54.152651]  [<c10a5805>] fput+0xe0/0x16a
[   54.152656]  [<c1090c9e>] remove_vma+0x28/0x47
[   54.152661]  [<c1091811>] ? arch_unmap_area_topdown+0x0/0x18
[   54.152666]  [<c1091a60>] do_munmap+0x1e8/0x200             
[   54.152672]  [<c1091b8b>] sys_munmap+0x32/0x42 
[   54.152677]  [<c10027d3>] sysenter_do_call+0x12/0x32



	Sergey

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