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From: Roland Dreier <rdreier@cisco.com>
To: "Tony Luck" <tony.luck@intel.com>
Cc: "David Miller" <davem@davemloft.net>,
	mingo@elte.hu, linux-kernel@vger.kernel.org
Subject: Re: Strange hang on ia64 with CONFIG_PRINTK_TIME=y
Date: Thu, 14 Feb 2008 14:04:05 -0800	[thread overview]
Message-ID: <ada7ih7qjoq.fsf@cisco.com> (raw)
In-Reply-To: <12c511ca0802141327j6e31e8c2tee1d679053b604fc@mail.gmail.com> (Tony Luck's message of "Thu, 14 Feb 2008 13:27:58 -0800")

 > >  The strange thing is that Ingo's patch to make cpu_clock() a NOP until
 > >  after sched_init() didn't fix things for me...

 > Very strange.  I threw in an output line counter into the printk code() ... if I
 > disable the timestamps for the first 30 lines, then everything is good (so the
 > basic timestamping code does still work on ia64). But I would have thought
 > that Ingo's delay until sched_init() ought to be long enough too. Clearly I
 > need to figure out exactly what needs to be initialized to prevent the
 > hang/crash.

I guess sched_init() is too early... it does seem really strange to
me, but I just double checked with Ingo's patch and it does indeed
hang.  The slow way to make progress is just to go through
start_kernel() line-by-line and enable cpu_clock() at each stage, and
see where it stops hanging.  I'll give that a shot as a background
process (my ia64 box takes quite a while to boot, so each test takes a
long time but requires very little of my attention).

  reply	other threads:[~2008-02-14 22:04 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-13  6:24 Roland Dreier
2008-02-13  7:01 ` David Miller
2008-02-13 12:57   ` Ingo Molnar
2008-02-13 13:02     ` Ingo Molnar
2008-02-14  0:26       ` Roland Dreier
2008-02-13 13:03     ` David Miller
2008-02-13 13:06       ` Ingo Molnar
2008-02-14  0:59       ` Tony Luck
2008-02-14  1:04         ` David Miller
2008-02-14  3:33           ` Tony Luck
2008-02-14  3:47             ` Roland Dreier
2008-02-14 18:24               ` Luck, Tony
2008-02-14 21:27               ` Tony Luck
2008-02-14 22:04                 ` Roland Dreier [this message]
2008-02-14 22:23                   ` Luck, Tony
2008-02-15  2:17                     ` Tony Luck
2008-02-19 22:40                       ` Tony Luck
2008-02-20  8:12                         ` Ingo Molnar
2008-02-20  8:15                           ` David Miller
2008-02-20 23:35                         ` Roland Dreier
2008-02-20 23:36                         ` Roland Dreier

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