Messages in this thread | | | Subject | Re: [linux-next-20130422] Bug in SLAB? | From | Tetsuo Handa <> | Date | Tue, 2 Jul 2013 06:45:27 +0900 |
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Andrew Morton wrote: > On Tue, 7 May 2013 14:28:49 +0000 Christoph Lameter <cl@linux.com> wrote: > > > On Tue, 7 May 2013, Tetsuo Handa wrote: > > > > > > These are exclusively from the module load. So the kernel seems to be > > > > clean of large kmalloc's ? > > > > > > > There are modules (e.g. TOMOYO) which do not check for KMALLOC_MAX_SIZE limit > > > and expect kmalloc() larger than KMALLOC_MAX_SIZE bytes to return NULL. > > > > Dont do that. Please fix these things. > > Slab should return NULL for a request greater than KMALLOC_MAX_SIZE. > For heaven's sake don't break that!
The patch that fixes above things (commit 6286ae97) went to 3.10.
> What's going on with this bug, btw? This: > > --- a/mm/slab.c~slab-fix-init_lock_keys > +++ a/mm/slab.c > @@ -565,7 +565,7 @@ static void init_node_lock_keys(int q) > if (slab_state < UP) > return; > > - for (i = 1; i < PAGE_SHIFT + MAX_ORDER; i++) { > + for (i = 1; i <= KMALLOC_SHIFT_HIGH; i++) { > struct kmem_cache_node *n; > struct kmem_cache *cache = kmalloc_caches[i]; > > > still seems to be unapplied. > The patch that fixes oops and panic on early boot on architectures with PAGE_SHIFT + MAX_ORDER > 26 missed 3.10.
> I've read through the thread trying to work out what the end-user > impact of that fix is, but it's all clear as mud. It's possible that > the end-user effect is `kernel locks up after printing "Booting the > kernel"'. Or maybe not. > > And if the above patch does indeed fix something significant, we might > need a -stable backport. >
Somebody needs this patch when debugging with CONFIG_LOCKDEP=y on architectures with PAGE_SHIFT + MAX_ORDER > 26 .
> Can we get some clarity here please? >
Thank you for adding to -mm. But please delete
Tetsuo said: : It hangs (with CPU#0 spinning) immediately after printing : : Decompressing Linux... Parsing ELF... done. : Booting the kernel. : : lines.
lines from "+ slab-fix-init_lock_keys.patch added to -mm tree", for these lines are fixed by commit 8a965b3b. Though the same symptom would appear if hitting this PAGE_SHIFT + MAX_ORDER > 26 bug, I can't confirm the symptom for environments which I don't have.
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