I'm seeing lockdep warning about a potential lock inversion between &mm->mmap_sem and &inode->i_mutex in NFS (see attachment).
Unfortunately the basis for the warning appears to be the behaviour in ext3(???). AFAICS there is no way for NFS to share an inode->i_mutex with ext3. What to do? Trond
======================================================= [ INFO: possible circular locking dependency detected ] 2.6.23-rc7-g8809e921 #1 ------------------------------------------------------- beagle-build-in/24375 is trying to acquire lock: (&mm->mmap_sem){----}, at: [<c05a2887>] do_page_fault+0x17d/0x591 but task is already holding lock: (&inode->i_mutex){--..}, at: [<c059f9e3>] mutex_lock+0x1c/0x1f which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&inode->i_mutex){--..}: [<c043d4da>] __lock_acquire+0x9f3/0xba6 [<c043da62>] lock_acquire+0x5f/0x78 [<c059f832>] __mutex_lock_slowpath+0xe5/0x27a [<c059f9e3>] mutex_lock+0x1c/0x1f [<f8c92495>] nfs_revalidate_mapping+0x64/0x9c [nfs] [<f8c8ff2a>] nfs_file_mmap+0x46/0x75 [nfs] [<c046097c>] mmap_region+0x1ea/0x3b8 [<c0460e9b>] do_mmap_pgoff+0x27b/0x2da [<c0407d77>] sys_mmap2+0x9b/0xb5 [<c040405e>] sysenter_past_esp+0x5f/0x99 [<ffffffff>] 0xffffffff -> #0 (&mm->mmap_sem){----}: [<c043d3c6>] __lock_acquire+0x8df/0xba6 [<c043da62>] lock_acquire+0x5f/0x78 [<c04360db>] down_read+0x3a/0x4c [<c05a2887>] do_page_fault+0x17d/0x591 [<c05a1382>] error_code+0x72/0x78 [<f88acaac>] call_filldir+0xac/0xc3 [ext3] [<f88acdb2>] ext3_readdir+0x217/0x5e5 [ext3] [<c04798a1>] vfs_readdir+0x67/0x93 [<c0479af6>] sys_getdents+0x5f/0x9d [<c040405e>] sysenter_past_esp+0x5f/0x99 [<ffffffff>] 0xffffffff other info that might help us debug this: 1 lock held by beagle-build-in/24375: #0: (&inode->i_mutex){--..}, at: [<c059f9e3>] mutex_lock+0x1c/0x1f stack backtrace: [<c04050ee>] show_trace_log_lvl+0x1a/0x2f [<c0405b58>] show_trace+0x12/0x14 [<c0405b70>] dump_stack+0x16/0x18 [<c043bc05>] print_circular_bug_tail+0x5f/0x68 [<c043d3c6>] __lock_acquire+0x8df/0xba6 [<c043da62>] lock_acquire+0x5f/0x78 [<c04360db>] down_read+0x3a/0x4c [<c05a2887>] do_page_fault+0x17d/0x591 [<c05a1382>] error_code+0x72/0x78 [<f88acaac>] call_filldir+0xac/0xc3 [ext3] [<f88acdb2>] ext3_readdir+0x217/0x5e5 [ext3] [<c04798a1>] vfs_readdir+0x67/0x93 [<c0479af6>] sys_getdents+0x5f/0x9d [<c040405e>] sysenter_past_esp+0x5f/0x99 =======================