lkml.org 
[lkml]   [2016]   [Jan]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 3.16.y-ckt 115/126] sched/core: Clear the root_domain cpumasks in init_rootdomain()
    Date
    3.16.7-ckt22 -stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Xunlei Pang <xlpang@redhat.com>

    commit 8295c69925ad53ec32ca54ac9fc194ff21bc40e2 upstream.

    root_domain::rto_mask allocated through alloc_cpumask_var()
    contains garbage data, this may cause problems. For instance,
    When doing pull_rt_task(), it may do useless iterations if
    rto_mask retains some extra garbage bits. Worse still, this
    violates the isolated domain rule for clustered scheduling
    using cpuset, because the tasks(with all the cpus allowed)
    belongs to one root domain can be pulled away into another
    root domain.

    The patch cleans the garbage by using zalloc_cpumask_var()
    instead of alloc_cpumask_var() for root_domain::rto_mask
    allocation, thereby addressing the issues.

    Do the same thing for root_domain's other cpumask memembers:
    dlo_mask, span, and online.

    Signed-off-by: Xunlei Pang <xlpang@redhat.com>
    Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Mike Galbraith <efault@gmx.de>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Steven Rostedt <rostedt@goodmis.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Link: http://lkml.kernel.org/r/1449057179-29321-1-git-send-email-xlpang@redhat.com
    Signed-off-by: Ingo Molnar <mingo@kernel.org>
    Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
    ---
    kernel/sched/core.c | 8 ++++----
    1 file changed, 4 insertions(+), 4 deletions(-)

    diff --git a/kernel/sched/core.c b/kernel/sched/core.c
    index c80729679806..0417f4b1a5f3 100644
    --- a/kernel/sched/core.c
    +++ b/kernel/sched/core.c
    @@ -5486,13 +5486,13 @@ static int init_rootdomain(struct root_domain *rd)
    {
    memset(rd, 0, sizeof(*rd));

    - if (!alloc_cpumask_var(&rd->span, GFP_KERNEL))
    + if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL))
    goto out;
    - if (!alloc_cpumask_var(&rd->online, GFP_KERNEL))
    + if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL))
    goto free_span;
    - if (!alloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL))
    + if (!zalloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL))
    goto free_online;
    - if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
    + if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
    goto free_dlo_mask;

    init_dl_bw(&rd->dl_bw);

    \
     
     \ /
      Last update: 2016-01-06 12:21    [W:2.609 / U:0.024 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site