Messages in this thread | | | Date | Sun, 27 Jan 2008 22:17:36 +0100 | From | "Vegard Nossum" <> | Subject | Re: lib/idr.c: initialize struct idr_layer |
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On Jan 27, 2008 10:00 PM, Pekka Enberg <penberg@cs.helsinki.fi> wrote: > Hi Vegard, > > On Jan 27, 2008 10:07 PM, Vegard Nossum <vegard.nossum@gmail.com> wrote: > > I am testing my kmemcheck patches, and it has come up with a couple of > > uses of uninitialized memory in lib/idr.c. These are (the line numbers > > may differ slightly): > > [snip] > > > @@ -39,12 +39,16 @@ static struct idr_layer *alloc_layer(struct idr *idp) > > { > > struct idr_layer *p; > > unsigned long flags; > > + int i; > > > > spin_lock_irqsave(&idp->lock, flags); > > if ((p = idp->id_free)) { > > idp->id_free = p->ary[0]; > > idp->id_free_cnt--; > > - p->ary[0] = NULL; > > + p->bitmap = 0; > > + for(i = 0; i < ARRAY_SIZE(p->ary); ++i) > > + p->ary[i] = NULL; > > + p->count = 0; > > But aren't these zeroed by idr_cache_ctor() already?
That would make sense. However...
idr_layer_cache is only used for allocations from idr_pre_get(). idr_pre_get() is only called from ida_pre_get().
If this analysis is correct, can this mean that the user has failed to call ida_pre_get() before idr_get_new() was called?
Though in this case, idr_pre_get() actually *is* called first. Hmm... I think there's a pretty big chance that kmemcheck is at fault :-(
Vegard
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