lkml.org 
[lkml]   [2011]   [Jun]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Subject[PATCH] lockdep: Fix lock_is_held on recursion
    From
    Date
    Subject: lockdep: Fix lock_is_held on recursion
    From: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Date: Mon Jun 06 12:32:43 CEST 2011

    The main lock_is_held() user is lockdep_assert_held(), avoid false
    assertions in lockdep_off() sections by unconditionally reporting the
    lock is taken.

    [ the reason this is important is a lockdep_assert_held() in ttwu()
    which triggers a warning under lockdep_off() as in printk() which
    can trigger another wakeup and lock up due to spinlock recursion ]

    Reported-and-tested-by: Arne Jansen <lists@die-jansens.de>
    Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
    ---
    Index: linux-2.6/kernel/lockdep.c
    ===================================================================
    --- linux-2.6.orig/kernel/lockdep.c
    +++ linux-2.6/kernel/lockdep.c
    @@ -3426,7 +3426,7 @@ int lock_is_held(struct lockdep_map *loc
    int ret = 0;

    if (unlikely(current->lockdep_recursion))
    - return ret;
    + return 1; /* avoid false negative lockdep_assert_held */

    raw_local_irq_save(flags);
    check_flags(flags);



    \
     
     \ /
      Last update: 2011-06-07 00:17    [W:0.020 / U:1.108 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site