lkml.org 
[lkml]   [2018]   [Dec]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH v3 16/24] locking/lockdep: Retain the class key and name while freeing a lock class
    On Thu, Dec 06, 2018 at 05:11:40PM -0800, Bart Van Assche wrote:
    > The next patch in this series uses the class name in code that
    > detects calls to lock_acquire() while a class key is being freed. Hence
    > retain the class name for lock classes that are being freed.

    From readin the discussion with v2; you meant to say: 'uses the class
    name pointer', right? You're not actually ever going to dereference it,
    since that would be a UaF.

    >
    > Cc: Peter Zijlstra <peterz@infradead.org>
    > Cc: Waiman Long <longman@redhat.com>
    > Cc: Johannes Berg <johannes@sipsolutions.net>
    > Signed-off-by: Bart Van Assche <bvanassche@acm.org>
    > ---
    > kernel/locking/lockdep.c | 4 +---
    > 1 file changed, 1 insertion(+), 3 deletions(-)
    >
    > diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
    > index ecd92969674c..92bdb187987f 100644
    > --- a/kernel/locking/lockdep.c
    > +++ b/kernel/locking/lockdep.c
    > @@ -4147,10 +4147,8 @@ static void zap_class(struct lock_class *class)
    > * Unhash the class and remove it from the all_lock_classes list:
    > */
    > hlist_del_rcu(&class->hash_entry);
    > + class->hash_entry.pprev = NULL;
    > list_del(&class->lock_entry);
    > -
    > - RCU_INIT_POINTER(class->key, NULL);
    > - RCU_INIT_POINTER(class->name, NULL);
    > }
    >
    > static inline int within(const void *addr, void *start, unsigned long size)
    > --
    > 2.20.0.rc2.403.gdbc3b29805-goog
    >

    \
     
     \ /
      Last update: 2018-12-07 11:22    [W:4.096 / U:0.024 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site