Re: 2.6.17-rc6-mm1

[Dave Jones <davej@redhat.com>]

On Wed, Jun 07, 2006 at 10:47:24AM -0700, Andrew Morton wrote:
 > 
 > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.17-rc6/2.6.17-rc6-mm1/
 > 
 > - Many more lockdep updates

Needs more.

====================================
[ BUG: possible deadlock detected! ]
------------------------------------
nfsd/11429 is trying to acquire lock:
 (&inode->i_mutex){--..}, at: [<c032286a>] mutex_lock+0x21/0x24

but task is already holding lock:
 (&inode->i_mutex){--..}, at: [<c032286a>] mutex_lock+0x21/0x24

which could potentially lead to deadlocks!

other info that might help us debug this:
2 locks held by nfsd/11429:
 #0:  (hash_sem){----}, at: [<d10d0364>] exp_readlock+0x0/0x3e [nfsd]
 #1:  (&inode->i_mutex){--..}, at: [<c032286a>] mutex_lock+0x21/0x24

stack backtrace:
 [<c0104966>] show_trace_log_lvl+0x54/0xfd
 [<c0104f1a>] show_trace+0xd/0x10
 [<c010502f>] dump_stack+0x19/0x1b
 [<c013b2d4>] __lockdep_acquire+0x8f6/0x912
 [<c013b346>] lockdep_acquire+0x56/0x6f
 [<c03226cf>] __mutex_lock_slowpath+0xae/0x228
 [<c032286a>] mutex_lock+0x21/0x24
 [<d10cdb64>] nfsd_setattr+0x2d3/0x49f [nfsd]
 [<d10ceecd>] nfsd_create_v3+0x319/0x4aa [nfsd]
 [<d10d413e>] nfsd3_proc_create+0x125/0x135 [nfsd]
 [<d10ca0d4>] nfsd_dispatch+0xc0/0x178 [nfsd]
 [<d0ee89e9>] svc_process+0x38d/0x5d5 [sunrpc]
 [<d10ca581>] nfsd+0x18b/0x302 [nfsd]
 [<c0102005>] kernel_thread_helper+0x5/0xb


It's too close to bedtime for me, and on a cursory examination,
I don't even see where nfsd_setattr touches a mutex.

This was triggered by a simple 'touch foo' over an nfs v3 mount.

		Dave

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