Re: [tip:core/rcu] rcu: Add diagnostic check for a possible CPU-hotplug race

Ingo Molnar
2009-08-04T08:21:06Z

* Gautham R Shenoy <ego@in.ibm.com> wrote:

> On Mon, Aug 03, 2009 at 09:04:58AM +0200, Ingo Molnar wrote:
> > [ 0.010000] Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar
> > [ 0.010000] ... MAX_LOCKDEP_SUBCLASSES: 8
> > [ 0.010000] ... MAX_LOCK_DEPTH: 48
> > [ 0.010000] ... MAX_LOCKDEP_KEYS: 8191
> > [ 0.010000] ... CLASSHASH_SIZE: 4096
> > [ 0.010000] ... MAX_LOCKDEP_ENTRIES: 16384
> > [ 0.010000] ... MAX_LOCKDEP_CHAINS: 32768
> > [ 0.010000] ... CHAINHASH_SIZE: 16384
> > [ 0.010000] memory used by lock dependency info: 5823 kB
> > [ 0.010000] per task-struct memory footprint: 1920 bytes
> > [ 0.010000] ------------------------
> > [ 0.010000] | Locking API testsuite:
> > [ 0.010000] ----------------------------------------------------------------------------
> > [ 0.010000] | spin |wlock |rlock |mutex | wsem | rsem |
> > [ 0.010000] --------------------------------------------------------------------------
> > [ 0.010000] A-A deadlock:failed|failed| ok |failed|failed|failed|
> > [ 0.010000] A-B-B-A deadlock:failed|failed| ok |failed|failed|failed|
> > [ 0.010000] A-B-B-C-C-A deadlock:failed|failed| ok |failed|failed|failed|
> > [ 0.010000] A-B-C-A-B-C deadlock:failed|failed| ok |failed|failed|failed|
> > [ 0.010000] A-B-B-C-C-D-D-A deadlock:failed|failed| ok |failed|failed|failed|
> > [ 0.010000] A-B-C-D-B-D-D-A deadlock:failed|failed| ok |failed|failed|failed|
> > [ 0.010000] A-B-C-D-B-C-D-A deadlock:failed|failed| ok |failed|failed|failed|
> > [ 0.010000] double unlock: ok | ok | ok | ok | ok | ok |
> > [ 0.010000] initialize held: ok | ok | ok | ok | ok | ok |
> > [ 0.010000] bad unlock order: ok | ok | ok | ok | ok | ok |
> > [ 0.010000] --------------------------------------------------------------------------
> > [ 0.010000] recursive read-lock: | ok | |failed|
> > [ 0.010000] recursive read-lock #2: | ok | |failed|
> > [ 0.010000] mixed read-write-lock: |failed| |failed|
> > [ 0.010000] mixed write-read-lock: |failed| |failed|
> > [ 0.010000] --------------------------------------------------------------------------
> > [ 0.010000] hard-irqs-on + irq-safe-A/12:failed|failed| ok |
> > [ 0.010000] soft-irqs-on + irq-safe-A/12:failed|failed| ok |
> > [ 0.010000] hard-irqs-on + irq-safe-A/21:failed|failed| ok |
> > [ 0.010000] soft-irqs-on + irq-safe-A/21:failed|failed| ok |
> > [ 0.010000] sirq-safe-A => hirqs-on/12:failed|failed| ok |
> > [ 0.010000] sirq-safe-A => hirqs-on/21:failed|failed| ok |
> > [ 0.010000] hard-safe-A + irqs-on/12:failed|failed| ok |
> > [ 0.010000] soft-safe-A + irqs-on/12:failed|failed| ok |
> > [ 0.010000] hard-safe-A + irqs-on/21:failed|failed| ok |
> > [ 0.010000] soft-safe-A + irqs-on/21:failed|failed| ok |
> > [ 0.010000] hard-safe-A + unsafe-B #1/123:failed|failed| ok |
> > [ 0.010000] soft-safe-A + unsafe-B #1/123:failed|failed| ok |
> > [ 0.010000] hard-safe-A + unsafe-B #1/132:failed|failed| ok |
> > [ 0.010000] soft-safe-A + unsafe-B #1/132:failed|failed| ok |
> > [ 0.010000] hard-safe-A + unsafe-B #1/213:failed|failed| ok |
> > [ 0.010000] soft-safe-A + unsafe-B #1/213:failed|failed| ok |
> > [ 0.010000] hard-safe-A + unsafe-B #1/231:failed|failed| ok |
> > [ 0.010000] soft-safe-A + unsafe-B #1/231:failed|failed| ok |
> > [ 0.010000] hard-safe-A + unsafe-B #1/312:failed|failed| ok |
> > [ 0.010000] soft-safe-A + unsafe-B #1/312:failed|failed| ok |
> > [ 0.010000] hard-safe-A + unsafe-B #1/321:failed|failed| ok |
> > [ 0.010000] soft-safe-A + unsafe-B #1/321:failed|failed| ok |
> > [ 0.010000] hard-safe-A + unsafe-B #2/123:failed|failed| ok |
> > [ 0.010000] soft-safe-A + unsafe-B #2/123:failed|failed| ok |
> > [ 0.010000] hard-safe-A + unsafe-B #2/132:failed|failed| ok |
> > [ 0.010000] soft-safe-A + unsafe-B #2/132:failed|failed| ok |
> > [ 0.010000] hard-safe-A + unsafe-B #2/213:failed|failed| ok |
> > [ 0.010000] soft-safe-A + unsafe-B #2/213:failed|failed| ok |
> > [ 0.010000] hard-safe-A + unsafe-B #2/231:failed|failed| ok |
> > [ 0.010000] soft-safe-A + unsafe-B #2/231:failed|failed| ok |
> > [ 0.010000] hard-safe-A + unsafe-B #2/312:failed|failed| ok |
> > [ 0.010000] soft-safe-A + unsafe-B #2/312:failed|failed| ok |
> > [ 0.010000] hard-safe-A + unsafe-B #2/321:failed|failed| ok |
> > [ 0.010000] soft-safe-A + unsafe-B #2/321:failed|failed| ok |
> > [ 0.010000] hard-irq lock-inversion/123:failed|failed| ok |
> > [ 0.010000] soft-irq lock-inversion/123:failed|failed| ok |
> > [ 0.010000] hard-irq lock-inversion/132:failed|failed| ok |
> > [ 0.010000] soft-irq lock-inversion/132:failed|failed| ok |
> > [ 0.010000] hard-irq lock-inversion/213:failed|failed| ok |
> > [ 0.010000] soft-irq lock-inversion/213:failed|failed| ok |
> > [ 0.010000] hard-irq lock-inversion/231:failed|failed| ok |
> > [ 0.010000] soft-irq lock-inversion/231:failed|failed| ok |
> > [ 0.010000] hard-irq lock-inversion/312:failed|failed| ok |
> > [ 0.010000] soft-irq lock-inversion/312:failed|failed| ok |
> > [ 0.010000] hard-irq lock-inversion/321:failed|failed| ok |
> > [ 0.010000] soft-irq lock-inversion/321:failed|failed| ok |
> > [ 0.010000] hard-irq read-recursion/123: ok |
> > [ 0.010000] soft-irq read-recursion/123: ok |
> > [ 0.010000] hard-irq read-recursion/132: ok |
> > [ 0.010000] soft-irq read-recursion/132: ok |
> > [ 0.010000] hard-irq read-recursion/213: ok |
> > [ 0.010000] soft-irq read-recursion/213: ok |
> > [ 0.010000] hard-irq read-recursion/231: ok |
> > [ 0.010000] soft-irq read-recursion/231: ok |
> > [ 0.010000] hard-irq read-recursion/312: ok |
> > [ 0.010000] soft-irq read-recursion/312: ok |
> > [ 0.010000] hard-irq read-recursion/321: ok |
> > [ 0.010000] soft-irq read-recursion/321: ok |
> > [ 0.010000] --------------------------------------------------------
> > [ 0.010000] 133 out of 218 testcases failed, as expected. |
> > [ 0.010000] ----------------------------------------------------
>
> Hmm.. I tried to reproduce this on a similar 2 CPU machine running
> linux-2.6.31-rc5-tip. However, I couldn't reproduce this WARN_ON.
>
> That aside, in my case, all the 218 lockdep test cases passed,
> while this bootlog shows quite a few failures.
> So, wondering if I am testing the right kernel version.

hm, maybe i sent the wrong config.

I'll try to reproduce it once more and will double check.

Ingo