lkml.org 
[lkml]   [2012]   [Sep]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: [PATCH] slab: fix the DEADLOCK issue on l3 alien lock
    From
    On Tue, Sep 11, 2012 at 5:50 AM, Michael Wang
    <wangyun@linux.vnet.ibm.com> wrote:
    > On 09/08/2012 04:39 PM, Pekka Enberg wrote:
    >> On Fri, Sep 7, 2012 at 1:29 AM, Paul E. McKenney
    >> <paulmck@linux.vnet.ibm.com> wrote:
    >>> On Thu, Sep 06, 2012 at 11:05:11AM +0800, Michael Wang wrote:
    >>>> On 09/05/2012 09:55 PM, Christoph Lameter wrote:
    >>>>> On Wed, 5 Sep 2012, Michael Wang wrote:
    >>>>>
    >>>>>> Since the cachep and cachep->slabp_cache's l3 alien are in the same lock class,
    >>>>>> fake report generated.
    >>>>>
    >>>>> Ahh... That is a key insight into why this occurs.
    >>>>>
    >>>>>> This should not happen since we already have init_lock_keys() which will
    >>>>>> reassign the lock class for both l3 list and l3 alien.
    >>>>>
    >>>>> Right. I was wondering why we still get intermitted reports on this.
    >>>>>
    >>>>>> This patch will invoke init_lock_keys() after we done enable_cpucache()
    >>>>>> instead of before to avoid the fake DEADLOCK report.
    >>>>>
    >>>>> Acked-by: Christoph Lameter <cl@linux.com>
    >>>>
    >>>> Thanks for your review.
    >>>>
    >>>> And add Paul to the cc list(my skills on mailing is really poor...).
    >>>
    >>> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
    >>
    >> I'd also like to tag this for the stable tree to avoid bogus lockdep
    >> reports. How far back in release history should we queue this?
    > Hi, Pekka
    >
    > Sorry for the delayed reply, I try to find out the reason for commit
    > 30765b92 but not get it yet, so I add Peter to the cc list.
    >
    > The below patch for release 3.0.0 is the one to cause the bogus report.
    >
    > commit 30765b92ada267c5395fc788623cb15233276f5c
    > Author: Peter Zijlstra <peterz@infradead.org>
    > Date: Thu Jul 28 23:22:56 2011 +0200
    >
    > slab, lockdep: Annotate the locks before using them
    >
    > Fernando found we hit the regular OFF_SLAB 'recursion' before we
    > annotate the locks, cure this.
    >
    > The relevant portion of the stack-trace:
    >
    > > [ 0.000000] [<c085e24f>] rt_spin_lock+0x50/0x56
    > > [ 0.000000] [<c04fb406>] __cache_free+0x43/0xc3
    > > [ 0.000000] [<c04fb23f>] kmem_cache_free+0x6c/0xdc
    > > [ 0.000000] [<c04fb2fe>] slab_destroy+0x4f/0x53
    > > [ 0.000000] [<c04fb396>] free_block+0x94/0xc1
    > > [ 0.000000] [<c04fc551>] do_tune_cpucache+0x10b/0x2bb
    > > [ 0.000000] [<c04fc8dc>] enable_cpucache+0x7b/0xa7
    > > [ 0.000000] [<c0bd9d3c>] kmem_cache_init_late+0x1f/0x61
    > > [ 0.000000] [<c0bba687>] start_kernel+0x24c/0x363
    > > [ 0.000000] [<c0bba0ba>] i386_start_kernel+0xa9/0xaf
    >
    > Reported-by: Fernando Lopez-Lezcano <nando@ccrma.Stanford.EDU>
    > Acked-by: Pekka Enberg <penberg@kernel.org>
    > Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
    > Link: http://lkml.kernel.org/r/1311888176.2617.379.camel@laptop
    > Signed-off-by: Ingo Molnar <mingo@elte.hu>
    >
    > It moved init_lock_keys() before we build up the alien, so we failed to
    > reclass it.

    I've queued the patch for v3.7. Thanks!


    \
     
     \ /
      Last update: 2012-09-11 19:01    [W:0.070 / U:87.136 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site