Re: [2.6.31-rc2] hitting lockdep limits...

[Amerigo Wang <xiyou.wangcong@gmail.com>]

On Sun, Jul 05, 2009 at 07:19:34PM +0100, Daniel J Blueman wrote:
>Running 2.6.31-rc2, lockdep hits it's 2^18 stack trace limit [1],
>giving a warning [2]. It's clear the stacktrace here has no connection
>to the root problem.
>
>Nothing jumps out of the lockdep /proc files for what's eating up the
>limit - what's best to check for?


Hello,

Joao reported the same problem some days ago, I think Peter
will think about this.

>
>Thanks,
>  Daniel
>
>--- [1]
>
># cat lockdep_stats
> lock-classes:                         2034 [max: 8191]
> direct dependencies:                  8142 [max: 16384]
> indirect dependencies:               41755
> all direct dependencies:            886855
> dependency chains:                    7094 [max: 32768]
> dependency chain hlocks:             18066 [max: 163840]
> in-hardirq chains:                    1477
> in-softirq chains:                     617
> in-process chains:                    4221
> stack-trace entries:                262144 [max: 262144]
> combined max dependencies:      3856391688
> hardirq-safe locks:                   1063
> hardirq-unsafe locks:                  407
> softirq-safe locks:                   1088
> softirq-unsafe locks:                  366
> irq-safe locks:                       1096
> irq-unsafe locks:                      407
> hardirq-read-safe locks:                 0
> hardirq-read-unsafe locks:              47
> softirq-read-safe locks:                 0
> softirq-read-unsafe locks:              47
> irq-read-safe locks:                     0
> irq-read-unsafe locks:                  47
> uncategorized locks:                   107
> unused locks:                            0
> max locking depth:                       9
> max recursion depth:                     9
> chain lookup misses:                  7094
> chain lookup hits:                 5316747
> cyclic checks:                       59293
> cyclic-check recursions:             39761
> find-mask forwards checks:           16333
> find-mask forwards recursions:        5897
> find-mask backwards checks:         305195
> find-mask backwards recursions:     363516
> hardirq on events:                 6449896
> hardirq off events:                6449901
> redundant hardirq ons:                   0
> redundant hardirq offs:            6903417
> softirq on events:                   22975
> softirq off events:                  23003
> redundant softirq ons:                   0
> redundant softirq offs:                  0
> debug_locks:                             0
>
>--- [2]
>
>BUG: MAX_STACK_TRACE_ENTRIES too low!
>
>turning off the locking correctness validator.
>
>Pid: 2677, comm: rpc.statd Not tainted 2.6.31-rc2-272c #1
>
>Call Trace:
>
> [<ffffffff8101ad9f>] ? save_stack_trace+0x2f/0x50
>
> [<ffffffff8109c4be>] save_trace+0xbe/0xd0
>
> [<ffffffff8109c528>] add_lock_to_list+0x58/0xf0
>
> [<ffffffff81114d6b>] ? get_page_from_freelist+0x4db/0xa70
>
> [<ffffffff810a0870>] __lock_acquire+0xe40/0x1250
>
> [<ffffffff810a0d9e>] lock_acquire+0x11e/0x170
>
> [<ffffffff81114d6b>] ? get_page_from_freelist+0x4db/0xa70
>
> [<ffffffff81695110>] _spin_lock_irqsave+0x60/0xa0
>
> [<ffffffff81114d6b>] ? get_page_from_freelist+0x4db/0xa70
>
> [<ffffffff81114d6b>] get_page_from_freelist+0x4db/0xa70
>
> [<ffffffff8111556b>] __alloc_pages_nodemask+0x26b/0x880
>
> [<ffffffff81143bec>] alloc_pages_current+0x8c/0xe0
>
> [<ffffffff8114a922>] new_slab+0x382/0x390
>
> [<ffffffff8114c2d3>] __slab_alloc+0x203/0x6d0
>
> [<ffffffff815a7dce>] ? neigh_create+0x7e/0x690
>
> [<ffffffff815a7dce>] ? neigh_create+0x7e/0x690
>
> [<ffffffff8114d119>] kmem_cache_alloc+0x269/0x280
>
> [<ffffffff81071c69>] ? local_bh_enable_ip+0x119/0x1e0
>
> [<ffffffff815a7dce>] neigh_create+0x7e/0x690
>
> [<ffffffff81694cee>] ? _read_unlock_bh+0x3e/0x50
>
> [<ffffffff815a5a69>] ? neigh_lookup+0x179/0x190
>
> [<ffffffff81608dca>] arp_bind_neighbour+0xca/0xd0
>
> [<ffffffff815d9451>] rt_intern_hash+0x141/0x570
>
> [<ffffffff8109efbd>] ? trace_hardirqs_on+0xd/0x10
>
> [<ffffffff815dbcb7>] __ip_route_output_key+0x6b7/0xbc0
>
> [<ffffffff816990a2>] ? sub_preempt_count+0x142/0x150
>
> [<ffffffff815dc1e1>] ip_route_output_flow+0x21/0x70
>
> [<ffffffff816077e4>] udp_sendmsg+0x7c4/0x940
>
> [<ffffffff81322642>] ? debug_smp_processor_id+0x42/0x120
>
> [<ffffffff8160fb6a>] inet_sendmsg+0x4a/0x90
>
> [<ffffffff81587da4>] sock_sendmsg+0xe4/0x110
>
> [<ffffffff81086ea0>] ? autoremove_wake_function+0x0/0x40
>
> [<ffffffff8109fd08>] ? __lock_acquire+0x2d8/0x1250
>
> [<ffffffff810cd041>] ? audit_sockaddr+0x51/0x110
>
> [<ffffffff8158852c>] ? move_addr_to_kernel+0x5c/0x60
>
> [<ffffffff81588c0f>] sys_sendto+0x11f/0x190
>
> [<ffffffff8100d039>] ? retint_swapgs+0x13/0x1b
>
> [<ffffffff8109ef4d>] ? trace_hardirqs_on_caller+0x17d/0x1e0
>
> [<ffffffff81694a9e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
>
> [<ffffffff8100c4f2>] system_call_fastpath+0x16/0x1b
>
>-- 
>Daniel J Blueman
>--
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