Messages in this thread | | | Date | Wed, 3 Apr 2013 15:05:37 +0800 | Subject | Re: [PATCH] sysfs: check if one entry has been removed before freeing | From | Ming Lei <> |
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On Wed, Apr 3, 2013 at 1:35 PM, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > On Wed, Apr 03, 2013 at 11:52:39AM +0800, Ming Lei wrote: >> On Wed, Apr 3, 2013 at 11:04 AM, Dave Jones <davej@redhat.com> wrote: >> > On Wed, Apr 03, 2013 at 10:58:23AM +0800, Ming Lei wrote: >> > >> > > diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c >> > > index 1bf016b..328ef9b 100644 >> > > --- a/fs/sysfs/dir.c >> > > +++ b/fs/sysfs/dir.c >> > > @@ -268,6 +268,13 @@ void release_sysfs_dirent(struct sysfs_dirent * sd) >> > > */ >> > > parent_sd = sd->s_parent; >> > > >> > > + if (unlikely(!(sd->s_flags & SYSFS_FLAG_REMOVED))) { >> > > + printk(KERN_ERR "sysfs: free using entry: %s/%s\n", >> > > + parent_sd ? parent_sd->s_name : "", >> > > + sd->s_name); >> > > + BUG(); >> > > + } >> > >> > Please use WARN instead of BUG. For an in-ram filesystem like >> > sysfs, there's no real reason to lock-up the machine in this way >> > making it harder to debug. >> >> If WARN is used, the freed memory will be allocated to other >> kernel components, then sysfs may change the memory and cause >> destruction, so maybe it is better to use BUG to stop kernel. > > No, it's never ok to call BUG(), sorry, please fix this.
Sorry, could you explain it in a bit detail? IMO, it is really a bug when code runs here, and there are much similar BUG_ON() uses in current sysfs code too.
Thanks, -- Ming Lei
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