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From: "蒋雄伟(蒋冲)" <xiongwei.jiang@alibaba-inc.com>
To: <mingo@redhat.com>, <peterz@infradead.org>,
	<linux-kernel@vger.kernel.org>
Subject: panic at rb_next when do pick_next_task_fair
Date: Tue, 08 Nov 2016 17:52:03 +0800	[thread overview]
Message-ID: <001701d239a5$c2665880$47330980$@alibaba-inc.com> (raw)

Hi,all

We encountered the following panic  in 2.6.32 and 3.10.0:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
IP: [] rb_next+0x1/0x50

Call Trace:
 ? pick_next_task_fair+0x129/0x1d0
  [] __schedule+0x12a/0x910
  [] schedule+0x29/0x70
  [] futex_wait_queue_me+0xc4/0x120
  [] futex_wait+0x179/0x280
  [] ? hrtimer_get_res+0x50/0x50
  [] ? futex_wait_queue_me+0xa2/0x120
  [] do_futex+0xfe/0x5b0
  [] ? blk_finish_plug+0x14/0x40
  [] ? SyS_madvise+0x3c5/0x820
  [] SyS_futex+0x80/0x180
  [] system_call_fastpath+0x16/0x1b


It seems that after passing the check "if (!cfs_rq->nr_running)" ,
__pick_first_entity sometimes still return NULL, then leads to panic. 

Would you please give any advise?
Thanks a lot.

Best regards.

             reply	other threads:[~2016-11-08 10:02 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-08  9:52 蒋雄伟(蒋冲) [this message]
2016-11-08 13:11 ` Peter Zijlstra

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