Messages in this thread | | | Date | Sun, 4 Jan 2009 13:14:38 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH] Make treercu safe for suspend and resume |
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On Sun, Jan 04, 2009 at 09:41:08PM +0100, Eric Sesterhenn wrote: > * Paul E. McKenney (paulmck@linux.vnet.ibm.com) wrote: > > Hello! > > > > Kudos to both Dhaval Giani and Jens Axboe for finding a bug in treercu > > that causes warnings after suspend-resume cycles in Dhaval's case and > > during stress tests in Jens's case. It would also probably cause failures > > if heavily stressed. The solution, ironically enough, is to revert to > > rcupreempt's code for initializing the dynticks state. And the patch > > even results in smaller code -- so what was I thinking??? > > > > This is 2.6.29 material, given that people really do suspend and resume > > Linux these days. ;-) > > sadly even with this patch i still get this oops when doing > modprobe rcutorture; sleep 2s; rmmod rcutorture
I would have been extremely surprised had that patch fixed this problem, but thank you very much for trying it out! What can I say, I worked on the easy ones first. ;-)
Thanx, Paul
> [ 74.413097] BUG: unable to handle kernel NULL pointer dereference at > (null) > [ 74.413424] IP: [<(null)>] (null) > [ 74.413651] Oops: 0000 [#1] PREEMPT DEBUG_PAGEALLOC > [ 74.413956] last sysfs file: /sys/block/ram9/range > [ 74.414039] Modules linked in: [last unloaded: rcutorture] > [ 74.414039] > [ 74.414039] Pid: 4997, comm: rcu_torture_wri Tainted: G W > (2.6.28-05692-g7d3b56b-dirty #167) System Name > [ 74.414039] EIP: 0060:[<00000000>] EFLAGS: 00010246 CPU: 0 > [ 74.414039] EIP is at 0x0 > [ 74.414039] EAX: d0afd130 EBX: 00000000 ECX: c01612a6 EDX: 00000006 > [ 74.414039] ESI: d0afd130 EDI: 0000001c EBP: c0b03fe0 ESP: c0b03fd4 > [ 74.414039] DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 > [ 74.414039] Process rcu_torture_wri (pid: 4997, ti=c0b03000 > task=c98bce00 task.ti=c988b000) > [ 74.414039] Stack: > [ 74.414039] c01612ad 00000200 00000001 c0b03ff8 c012aa97 0000000a > c988beac 00000046 > [ 74.414039] c012aa28 c988bebc c01042c2 > [ 74.414039] Call Trace: > [ 74.414039] [<c01612ad>] ? rcu_process_callbacks+0x65/0x79 > [ 74.414039] [<c012aa97>] ? __do_softirq+0x6f/0xf6 > [ 74.414039] [<c012aa28>] ? __do_softirq+0x0/0xf6 > [ 74.414039] <IRQ> <0> [<c012a9a5>] ? irq_exit+0x40/0x7c > [ 74.414039] [<c0110ce1>] ? smp_apic_timer_interrupt+0x68/0x73 > [ 74.414039] [<c0103521>] ? apic_timer_interrupt+0x2d/0x34 > [ 74.414039] [<c01219f7>] ? finish_task_switch+0x4d/0x8b > [ 74.414039] [<c014007b>] ? tick_check_oneshot_change+0xb1/0xf9 > [ 74.414039] [<c07a091f>] ? _spin_unlock_irq+0x2d/0x47 > [ 74.414039] [<c01219f7>] ? finish_task_switch+0x4d/0x8b > [ 74.414039] [<c01219aa>] ? finish_task_switch+0x0/0x8b > [ 74.414039] [<c079e366>] ? schedule+0x404/0x450 > [ 74.414039] [<c079e582>] ? schedule_timeout+0x70/0x95 > [ 74.414039] [<c012e13a>] ? process_timeout+0x0/0xf > [ 74.414039] [<c079e57d>] ? schedule_timeout+0x6b/0x95 > [ 74.414039] [<c079e5c0>] ? > schedule_timeout_uninterruptible+0x19/0x1b > [ 74.414039] [<c0136bcc>] ? kthread+0x3e/0x66 > [ 74.414039] [<c0136b8e>] ? kthread+0x0/0x66 > [ 74.414039] [<c0103643>] ? kernel_thread_helper+0x7/0x10 > [ 74.414039] Code: Bad EIP value. > [ 74.414039] EIP: [<00000000>] 0x0 SS:ESP 0068:c0b03fd4 > [ 74.422275] ---[ end trace 4eaa2a86a8e2da22 ]--- > [ 74.422406] Kernel panic - not syncing: Fatal exception in interrupt > > Greetings Eric
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