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Date: Thu, 7 May 2015 16:05:57 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Tejun Heo <tj@kernel.org>, NeilBrown <neilb@suse.de>
Subject: Re: pmu_dev_alloc; warning at at kernel/locking/lockdep.c:3002
 lockdep_init_map
Message-ID: <20150507140557.GV21418@twins.programming.kicks-ass.net>
References: <554B6E78.2090608@linux.intel.com>
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On Thu, May 07, 2015 at 02:54:00PM +0100, Tvrtko Ursulin wrote:
> 
> Hi,
> 
> 4.1.0-rc2 spews the below warning and disables lockdep for me at boot.
> 
> Any ideas?
> 
> May  7 11:58:20 skl kernel: [    6.066696] futex hash table entries: 1024 (order: 5, 131072 bytes)
> May  7 11:58:20 skl kernel: [    6.075774] BUG: key ffff88014973b850 not in .data!
> May  7 11:58:20 skl kernel: [    6.081369] ------------[ cut here ]------------
> May  7 11:58:20 skl kernel: [    6.086695] WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:3002 lockdep_init_map+0x14b/0x5e0()
> May  7 11:58:20 skl kernel: [    6.096928] DEBUG_LOCKS_WARN_ON(1)
> May  7 11:58:20 skl kernel: [    6.100659] Modules linked in:
> May  7 11:58:20 skl kernel: [    6.104433] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.1.0-rc2-150507+ #3
> May  7 11:58:20 skl kernel: [    6.112284] Hardware name: Intel Corporation Skylake Client platform/Skylake Y LPDDR3 RVP3, BIOS SKLSE2R1.86C.X070.R01.1501282110 01/28/2015
> May  7 11:58:20 skl kernel: [    6.126689]  0000000000000bba ffff880149e1fb88 ffffffff816213f8 ffffffff8109fcc6
> May  7 11:58:20 skl kernel: [    6.135381]  ffff880149e1fbd8 ffff880149e1fbc8 ffffffff810528e2 0000000000000000
> May  7 11:58:20 skl kernel: [    6.143992]  ffff880146428858 0000000000000000 0000000000000000 ffff88014973b838
> May  7 11:58:20 skl kernel: [    6.152682] Call Trace:
> May  7 11:58:20 skl kernel: [    6.155513]  [<ffffffff816213f8>] dump_stack+0x4c/0x6e
> May  7 11:58:20 skl kernel: [    6.161399]  [<ffffffff8109fcc6>] ? console_unlock+0x406/0x440
> May  7 11:58:20 skl kernel: [    6.168075]  [<ffffffff810528e2>] warn_slowpath_common+0xb2/0xe0
> May  7 11:58:20 skl kernel: [    6.174946]  [<ffffffff810529c6>] warn_slowpath_fmt+0x46/0x50
> May  7 11:58:20 skl kernel: [    6.181525]  [<ffffffff81093b6b>] lockdep_init_map+0x14b/0x5e0
> May  7 11:58:20 skl kernel: [    6.188202]  [<ffffffff811dc06a>] __kernfs_create_file+0x7a/0xf0
> May  7 11:58:20 skl kernel: [    6.195069]  [<ffffffff811dcb4e>] sysfs_add_file_mode_ns+0x16e/0x1b0
> May  7 11:58:20 skl kernel: [    6.202346]  [<ffffffff811dd92a>] internal_create_group+0x19a/0x280
> May  7 11:58:20 skl kernel: [    6.209515]  [<ffffffff811dda43>] sysfs_create_group+0x13/0x20
> May  7 11:58:20 skl kernel: [    6.216185]  [<ffffffff811dda88>] sysfs_create_groups+0x38/0x90
> May  7 11:58:20 skl kernel: [    6.222958]  [<ffffffff8145c3d6>] device_add+0x276/0x5d0
> May  7 11:58:20 skl kernel: [    6.229040]  [<ffffffff8110a80b>] pmu_dev_alloc+0x8b/0xd0
> May  7 11:58:20 skl kernel: [    6.235215]  [<ffffffff81d44c93>] ? perf_workqueue_init+0x61/0x61
> May  7 11:58:20 skl kernel: [    6.242184]  [<ffffffff81d44cd9>] perf_event_sysfs_init+0x46/0x95
> May  7 11:58:20 skl kernel: [    6.249144]  [<ffffffff81d44c93>] ? perf_workqueue_init+0x61/0x61
> May  7 11:58:20 skl kernel: [    6.256118]  [<ffffffff81000352>] do_one_initcall+0x122/0x1f0
> May  7 11:58:20 skl kernel: [    6.262700]  [<ffffffff81072e00>] ? parse_args+0x240/0x450
> May  7 11:58:20 skl kernel: [    6.268980]  [<ffffffff81d27126>] kernel_init_freeable+0x106/0x19a
> May  7 11:58:20 skl kernel: [    6.276045]  [<ffffffff81d26878>] ? loglevel+0x31/0x31
> May  7 11:58:20 skl kernel: [    6.281939]  [<ffffffff8161a380>] ? rest_init+0x140/0x140
> May  7 11:58:20 skl kernel: [    6.288120]  [<ffffffff8161a38e>] kernel_init+0xe/0xf0
> May  7 11:58:20 skl kernel: [    6.294004]  [<ffffffff81629e92>] ret_from_fork+0x42/0x70
> May  7 11:58:20 skl kernel: [    6.300186]  [<ffffffff8161a380>] ? rest_init+0x140/0x140
> May  7 11:58:20 skl kernel: [    6.306367] ---[ end trace 98f2b03275198a56 ]---
> May  7 11:58:20 skl kernel: [    6.311703] BUG: key ffff88014973b888 not in .data!
> May  7 11:58:20 skl kernel: [    6.317300] BUG: key ffff88014973b8c0 not in .data!
> May  7 11:58:20 skl kernel: [    6.322895] BUG: key ffff88014973b8f8 not in .data!
> May  7 11:58:20 skl kernel: [    6.329549] HugeTLB registered 2 MB page size, pre-allocated 0 pages

That's in sysfs magic mushroom land, lets Cc people who know about this.