On Tue, May 31, 2011 at 12:33:18PM +0200, Lukas Czerner wrote:
> On Tue, 31 May 2011, Lukas Czerner wrote:
> 
> > We need to take reference to the s_li_request after we take a mutex,
> > because it might be freed since then, hence result in accessing old
> > already freed memory. Also we should protect the whole
> > ext4_remove_li_request() because ext4_li_info might be in the process of
> > being freed in ext4_lazyinit_thread().
> > 
> > Signed-off-by: Lukas Czerner <[email protected]>
> > Reviewed-by: Eric Sandeen <[email protected]>
> > ---
> >  fs/ext4/super.c |   10 ++++++----
> >  1 files changed, 6 insertions(+), 4 deletions(-)
> > 
> > diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> > index fd51a4a..ed5e80e 100644
> > --- a/fs/ext4/super.c
> > +++ b/fs/ext4/super.c
> > @@ -2735,14 +2735,16 @@ static void ext4_remove_li_request(struct 
> > ext4_li_request *elr)
> >  
> >  static void ext4_unregister_li_request(struct super_block *sb)
> >  {
> > -   struct ext4_li_request *elr = EXT4_SB(sb)->s_li_request;
> > -
> > -   if (!ext4_li_info)
> > +   mutex_lock(&ext4_li_mtx);
> > +   if (!ext4_li_info) {
> > +           mutex_unlock(&ext4_li_mtx);
> >             return;
> > +   }
> >  
> >     mutex_lock(&ext4_li_info->li_list_mtx);
> > -   ext4_remove_li_request(elr);
> > +   ext4_remove_li_request(EXT4_SB(sb)->s_li_request);
> >     mutex_unlock(&ext4_li_info->li_list_mtx);
> > +   mutex_unlock(&ext4_li_mtx);
> >  }
> >  
> >  static struct task_struct *ext4_lazyinit_task;
> > 
> 
> 
> This is upstream commit 1bb933fb1fa8e4cb337a0d5dfd2ff4c0dc2073e8

Ok, and what stable kernel trees do you want to see it applied to?

thanks,

greg k-h

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