Messages in this thread | | | Date | Sun, 13 Aug 2006 18:51:02 -0700 | From | Andrew Morton <> | Subject | Re: CIFS & Lockdep warnings |
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On Mon, 14 Aug 2006 11:05:03 +1000 (EST) Srihari Vijayaraghavan <sriharivijayaraghavan@yahoo.com.au> wrote:
> This is observed on 2.6.18-rc4 on SUSE 10.1 x86 on > P-IV. The volume is question was mounted from a > Windows 2003 server. > > ======================================================= > [ INFO: possible circular locking dependency detected > ] > ------------------------------------------------------- > cp/11790 is trying to acquire lock: > (iprune_mutex){--..}, at: [<c029e364>] > mutex_lock+0x19/0x20 > > but task is already holding lock: > (&inode->i_mutex){--..}, at: [<c029e364>] > mutex_lock+0x19/0x20 > > which lock already depends on the new lock. > > > the existing dependency chain (in reverse order) is: > > -> #1 (&inode->i_mutex){--..}: > [<c012a1c0>] lock_acquire+0x56/0x73 > [<c029e205>] __mutex_lock_slowpath+0xa6/0x1ec > [<c029e364>] mutex_lock+0x19/0x20 > [<e3cd2b7a>] ntfs_put_inode+0x3e/0x79 [ntfs] > [<c0169ac1>] iput+0x33/0x70 > [<c017738e>] inotify_unmount_inodes+0x12e/0x15f > [<c016a55c>] invalidate_inodes+0x38/0xd1 > [<c01599b3>] generic_shutdown_super+0x5a/0x108 > [<c0159a81>] kill_block_super+0x20/0x36 > [<c0159b56>] deactivate_super+0x61/0x78 > [<c016c561>] mntput_no_expire+0x44/0x78 > [<c015f536>] path_release_on_umount+0x16/0x1d > [<c016d692>] sys_umount+0x1d2/0x208 > [<c016d6d5>] sys_oldumount+0xd/0xf > [<c0102cfb>] syscall_call+0x7/0xb
NTFS takes i_mutex inside iprune_mutex. NTFS _should_ be deadlocking because of this (iprune_mutex nests inside i_mutex on the write() path) but somehow it gets away with it.
> -> #0 (iprune_mutex){--..}: > [<c012a1c0>] lock_acquire+0x56/0x73 > [<c029e205>] __mutex_lock_slowpath+0xa6/0x1ec > [<c029e364>] mutex_lock+0x19/0x20 > [<c016a3a2>] shrink_icache_memory+0x33/0x1b5 > [<c0142b56>] shrink_slab+0xce/0x125 > [<c0143385>] try_to_free_pages+0x125/0x1cc > [<c013f8a8>] __alloc_pages+0x184/0x26d > [<c013ca52>] > generic_file_buffered_write+0x15a/0x53d > [<c013d175>] > __generic_file_aio_write_nolock+0x340/0x38d > [<c013d223>] generic_file_aio_write+0x61/0xb3 > [<e3d8a326>] cifs_file_aio_write+0x23/0x43 > [cifs] > [<c0153bb3>] do_sync_write+0x9d/0xce > [<c0154437>] vfs_write+0xaa/0x14e > [<c015496e>] sys_write+0x3a/0x61 > [<c0102cfb>] syscall_call+0x7/0xb
CIFS takes i_prune_mutex inside i_mutex.
There's no deadlock here. Arguably lockdep should be treating i_mutex in filesystem A as being a different class from i_mutex from filesystem B.
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