Messages in this thread | | | Date | Sat, 15 Jul 2006 22:19:42 -0700 | From | Andrew Morton <> | Subject | Re: 2.6.17-1.2145_FC5 mmap-related soft lockup |
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On Sat, 15 Jul 2006 10:07:26 -0700 "Gary Funck" <gary@intrepid.com> wrote:
> > A test program which allocates about 256M of MAP_ANONYMOUS mmap memory, > and then spawns 4 processess, where each process i writes to 1/4 of the > mapped memory, and then reads the memory written by > the process (i + 1)%4, triggers a soft lockup, when exiting. > Hardware: > dual core dual Opteron 275 (Tyan motherboard, 4G physical memory) > has been rock solid reliable. > > BUG: soft lockup detected on CPU#3! > > Call Trace: <IRQ> <ffffffff802b2fb5>{softlockup_tick+219} > <ffffffff8029708e>{update_process_times+66} > <ffffffff8027a3ed>{smp_local_timer_interrupt+35} > <ffffffff8027aa95>{smp_apic_timer_interrupt+65} > <ffffffff80263acb>{apic_timer_interrupt+135} <EOI> > <ffffffff8020e578>{__set_page_dirty_nobuffers+0} > <ffffffff8026a128>{_write_unlock_irq+11} > <ffffffff8020e62d>{__set_page_dirty_nobuffers+181} > <ffffffff80207af6>{unmap_vmas+1037} > <ffffffff8023c7d9>{exit_mmap+120} <ffffffff8023eda8>{mmput+44} > <ffffffff80215ece>{do_exit+599} > <ffffffff8024cacd>{debug_mutex_init+0} > <ffffffff80262f01>{tracesys+209} > > .. > > The test program runs successfully, but hangs several seconds upon exit. > > The hardware and software configuration has been solid for several months, > but > we have seen timer-related synchronization issues with recent kernels (where > ntp has to force a re-sync for example, and an occasional lost ticks > message). > > The test program mentioned above is more complicated than described, and > can't easily be reproduced in source form, but the binary could be > made available.
ah-hah. This sounds like the write_lock(tree_lock) starvation bug.
Are you able to confirm that setting CONFIG_DEBUG_SPINLOCK=n fixes it?
And are you able to get us a copy of that test app?
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