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 _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
