From: David Miller <davem@davemloft.net>
To: mroos@linux.ee
Cc: linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org
Subject: Re: RCU detected CPU 0 stall after panic on sparc64
Date: Sat, 12 Dec 2009 09:40:02 +0000 [thread overview]
Message-ID: <20091212.014002.173528710.davem@davemloft.net> (raw)
In-Reply-To: <alpine.SOC.1.00.0912121049030.26625@math.ut.ee>
From: Meelis Roos <mroos@linux.ee>
Date: Sat, 12 Dec 2009 10:54:19 +0200 (EET)
> I tried 2.6.32 git gaad3bf0 on a SMP sparc64 machine (Ultra Enterprise
> 250). For some reason my disks were not found (not important in this
> bugreport) and this resulted in panic (cannnot mount root). However, the
> machine kept going and got the below messages (RCU detected CPU 0 stall
> (t\x1000 jiffies)) from timer interrupts.
>
> This seems to be like a bug in RCU vs panic.
It's normal actually. A panic() just loops forever and the cpu never
goes through an RCU grace period again as a result, and this triggers
the debugging timer that detects this condition.
Probably the panic() code should disable that assertion check.
WARNING: multiple messages have this Message-ID (diff)
From: David Miller <davem@davemloft.net>
To: mroos@linux.ee
Cc: linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org
Subject: Re: RCU detected CPU 0 stall after panic on sparc64
Date: Sat, 12 Dec 2009 01:40:02 -0800 (PST) [thread overview]
Message-ID: <20091212.014002.173528710.davem@davemloft.net> (raw)
In-Reply-To: <alpine.SOC.1.00.0912121049030.26625@math.ut.ee>
From: Meelis Roos <mroos@linux.ee>
Date: Sat, 12 Dec 2009 10:54:19 +0200 (EET)
> I tried 2.6.32 git gaad3bf0 on a SMP sparc64 machine (Ultra Enterprise
> 250). For some reason my disks were not found (not important in this
> bugreport) and this resulted in panic (cannnot mount root). However, the
> machine kept going and got the below messages (RCU detected CPU 0 stall
> (t=1000 jiffies)) from timer interrupts.
>
> This seems to be like a bug in RCU vs panic.
It's normal actually. A panic() just loops forever and the cpu never
goes through an RCU grace period again as a result, and this triggers
the debugging timer that detects this condition.
Probably the panic() code should disable that assertion check.
next prev parent reply other threads:[~2009-12-12 9:40 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-12 8:54 RCU detected CPU 0 stall after panic on sparc64 Meelis Roos
2009-12-12 8:54 ` Meelis Roos
2009-12-12 9:40 ` David Miller [this message]
2009-12-12 9:40 ` David Miller
2009-12-14 20:25 ` Paul E. McKenney
2009-12-14 20:25 ` Paul E. McKenney
2009-12-14 21:02 ` David Miller
2009-12-14 21:02 ` David Miller
2009-12-14 23:15 ` Paul E. McKenney
2009-12-14 23:15 ` Paul E. McKenney
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