From: srivatsa.bhat@linux.vnet.ibm.com (Srivatsa S. Bhat)
To: kernelnewbies@lists.kernelnewbies.org
Subject: side effects of calling interruptible_sleep_on_timeout()
Date: Wed, 25 Apr 2012 15:56:14 +0530 [thread overview]
Message-ID: <4F97D146.4060304@linux.vnet.ibm.com> (raw)
In-Reply-To: <20120424220626.GA6655@peter>
On 04/25/2012 03:36 AM, Philipp Ittershagen wrote:
> Hi Devendra,
>
> On Tue, Apr 24, 2012 at 03:24:23PM +0530, devendra rawat wrote:
>> Hi,
>> A switch driver is causing soft lockup on Montavista Linux Kernel
>> 2.6.10 system.
>> While browsing through the code of the driver. I came across a snippet
>> where after disabling the interrupts
>> a call is made to interruptible_sleep_on_timeout().
>> The code snippet is like
>> cli();
>> init_waitqueue_head(&queue);
>> interruptible_sleep_on_timeout(&queue, USEC_TO_JIFFIES(usec));
>> thread_check_signals();
>> sti();
>> I need to know the side effect of this sort of code, can it be
>> responsible for the softlockup of the system ? Its a PowerPC based
>> system.
>
> you cannot call sleep functions after disabling interrupts, because no
> interrupt will arrive for the scheduler to see the timeout and resume your
> task.
>
Yes, that's right. Also, in general, sleeping inside atomic sections (eg.,
sections with interrupts disabled or preempt disabled) is wrong. There is a
config option in the kernel that you can use to enable
sleep-inside-atomic-section-checking (CONFIG_DEBUG_ATOMIC_SLEEP I believe),
which can help you pin-point such bugs easily.
Regards,
Srivatsa S. Bhat
next prev parent reply other threads:[~2012-04-25 10:26 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-24 9:54 side effects of calling interruptible_sleep_on_timeout() devendra rawat
2012-04-24 22:06 ` Philipp Ittershagen
2012-04-25 10:26 ` Srivatsa S. Bhat [this message]
2012-04-26 4:33 ` Arun KS
2012-04-26 8:03 ` Srivatsa S. Bhat
[not found] ` <E351E450E8B9F54684A699D42DC5ADF21FB079C4@MPBAGVEX02.corp.mphasis.com>
[not found] ` <CABOM9ZoJk5FMSPeFGrZhbS_raUdnpXYjZraJd0Ddm0E5E+n00A@mail.gmail.com>
[not found] ` <E351E450E8B9F54684A699D42DC5ADF21FB0812D@MPBAGVEX02.corp.mphasis.com>
[not found] ` <CABOM9ZqEyZh8Oe3hKp8wb6OhzqP+7mRiXRAYuD3+iWBPBNkUBg@mail.gmail.com>
[not found] ` <E351E450E8B9F54684A699D42DC5ADF21FB777E1@MPBAGVEX02.corp.mphasis.com>
2012-04-26 12:17 ` Arun KS
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