On Fri, 13 Jul 2012, Dave Jones wrote:
> Looks like calling futex() with garbage makes things unhappy.
Cc'ing Darren and Peter.
> [ 673.054286] BUG: unable to handle kernel NULL pointer dereference at
> 0000000000000028
> [ 673.055292] IP: [<ffffffff810d665e>] __lock_acquire+0x5e/0x1ae0
> [ 673.056225] PGD 1107c8067 PUD 11079c067 PMD 0
> [ 673.057224] Oops: 0000 [#1] SMP
> [ 673.058248] CPU 3
> [ 673.095668] <SNIP modules splat>
> [ 673.095669] Pid: 22872, comm: trinity-child3 Not tainted 3.5.0-rc6+ #107
> [ 673.095673] RIP: 0010:[<ffffffff810d665e>] [<ffffffff810d665e>]
> __lock_acquire+0x5e/0x1ae0
> [ 673.095679] RSP: 0000:ffff8801107c7a48 EFLAGS: 00010046
> [ 673.095679] RAX: 0000000000000082 RBX: 0000000000000000 RCX:
> 0000000000000000
> [ 673.095680] RDX: 0000000000000000 RSI: 0000000000000000 RDI:
> 0000000000000028
> [ 673.095681] RBP: ffff8801107c7b38 R08: 0000000000000002 R09:
> 0000000000000000
> [ 673.095682] R10: 0000000000000000 R11: 0000000000000001 R12:
> 0000000000000002
> [ 673.095683] R13: ffff8800a9144d20 R14: 0000000000000002 R15:
> 0000000000000028
> [ 673.095684] FS: 00007f4343491740(0000) GS:ffff880148200000(0000)
> knlGS:0000000000000000
> [ 673.095685] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 673.095686] CR2: 0000000000000028 CR3: 000000012d9ba000 CR4:
> 00000000001407e0
> [ 673.095687] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
> 0000000000000000
> [ 673.095688] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7:
> 0000000000000400
> [ 673.095690] Process trinity-child3 (pid: 22872, threadinfo
> ffff8801107c6000, task ffff8800a9144d20)
> [ 673.095690] Stack:
> [ 673.095691] ffff8801107c7a58 ffff8800a91455e0 0000000000000002
> ffff8800a9144d20
> [ 673.095695] 000000000000029f ffffffff82959908 ffff8801107c7b78
> 0000000000000082
> [ 673.095699] ffff8801107c7aa8 ffffffff816884f0 ffff8800a9144d20
> ffff88013f748000
> [ 673.095702] Call Trace:
> [ 673.095703] [<ffffffff816884f0>] ? _raw_spin_unlock_irq+0x30/0x60
> [ 673.095708] [<ffffffff810d941d>] ? trace_hardirqs_on_caller+0x15d/0x1e0
> [ 673.095710] [<ffffffff810d94ad>] ? trace_hardirqs_on+0xd/0x10
> [ 673.095713] [<ffffffff810d87ed>] lock_acquire+0xad/0x220
> [ 673.095715] [<ffffffff810e0104>] ? rt_mutex_finish_proxy_lock+0x34/0xd0
> [ 673.095717] [<ffffffff810d3958>] ? trace_hardirqs_off_caller+0x28/0xd0
> [ 673.095720] [<ffffffff81687de6>] _raw_spin_lock+0x46/0x80
> [ 673.095722] [<ffffffff810e0104>] ? rt_mutex_finish_proxy_lock+0x34/0xd0
> [ 673.095725] [<ffffffff810e0104>] rt_mutex_finish_proxy_lock+0x34/0xd0
> [ 673.095726] [<ffffffff810ddbd2>]
> futex_wait_requeue_pi.constprop.20+0x2d2/0x3d0
> [ 673.095730] [<ffffffff81097ff0>] ? update_rmtp+0x70/0x70
> [ 673.095733] [<ffffffff810993c4>] ? hrtimer_start_range_ns+0x14/0x20
> [ 673.095736] [<ffffffff810de42a>] do_futex+0xea/0xa20
> [ 673.095738] [<ffffffff810ad759>] ? local_clock+0x99/0xc0
> [ 673.095741] [<ffffffff81189443>] ? might_fault+0x53/0xb0
> [ 673.095746] [<ffffffff810dee67>] sys_futex+0x107/0x1a0
> [ 673.095749] [<ffffffff810d9400>] ? trace_hardirqs_on_caller+0x140/0x1e0
> [ 673.095751] [<ffffffff81691b6d>] system_call_fastpath+0x1a/0x1f
> [ 673.095755] Code: d8 45 0f 45 e0 4c 89 75 f0 4c 89 7d f8 85 c0 0f 84 f8 00
> 00 00 8b 05 e2 af fa 00 49 89 ff 89 f3 41 89 d2 85 c0 0f 84 02 01 00 00 <49>
> 8b 07 ba 01 00 00 00 48 3d 20 c4 0c 82 44 0f 44 e2 83 fb 01
> [ 673.095789] RIP [<ffffffff810d665e>] __lock_acquire+0x5e/0x1ae0
> [ 673.095791] RSP <ffff8801107c7a48>
> [ 673.095792] CR2: 0000000000000028
> [ 673.095793] ---[ end trace c26f1bd418342e06 ]---
>
WARN_ON(!&q.pi_state);
pi_mutex = &q.pi_state->pi_mutex;
ret = rt_mutex_finish_proxy_lock(pi_mutex, to, &rt_waiter, 1);
debug_rt_mutex_free_waiter(&rt_waiter);
So there is some weird way which causes q.pi_state = NULL. Dave, did
you see the warning before the oops happened ?
That futex stuff should be sent to outer space.
Thanks,
tglx
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