Re: [PATCH v6 00/37] Memory allocation profiling

Suren Baghdasaryan
2024-04-25T15:39:51Z

On Wed, Apr 24, 2024 at 8:26 PM Kent Overstreet
<kent.overstreet@linux.dev> wrote:
>
> On Wed, Apr 24, 2024 at 06:59:01PM -0700, Kees Cook wrote:
> > On Thu, Mar 21, 2024 at 09:36:22AM -0700, Suren Baghdasaryan wrote:
> > > Low overhead [1] per-callsite memory allocation profiling. Not just for
> > > debug kernels, overhead low enough to be deployed in production.
> >
> > Okay, I think I'm holding it wrong. With next-20240424 if I set:
> >
> > CONFIG_CODE_TAGGING=y
> > CONFIG_MEM_ALLOC_PROFILING=y
> > CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT=y
> >
> > My test system totally freaks out:
> >
> > ...
> > SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
> > Oops: general protection fault, probably for non-canonical address 0xc388d881e4808550: 0000 [#1] PREEMPT SMP NOPTI
> > CPU: 0 PID: 0 Comm: swapper Not tainted 6.9.0-rc5-next-20240424 #1
> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
> > RIP: 0010:__kmalloc_node_noprof+0xcd/0x560
> >
> > Which is:
> >
> > __kmalloc_node_noprof+0xcd/0x560:
> > __slab_alloc_node at mm/slub.c:3780 (discriminator 2)
> > (inlined by) slab_alloc_node at mm/slub.c:3982 (discriminator 2)
> > (inlined by) __do_kmalloc_node at mm/slub.c:4114 (discriminator 2)
> > (inlined by) __kmalloc_node_noprof at mm/slub.c:4122 (discriminator 2)
> >
> > Which is:
> >
> > tid = READ_ONCE(c->tid);
> >
> > I haven't gotten any further than that; I'm EOD. Anyone seen anything
> > like this with this series?
>
> I certainly haven't. That looks like some real corruption, we're in slub
> internal data structures and derefing a garbage address. Check kasan and
> all that?

Hi Kees,
I tested next-20240424 yesterday with defconfig and
CONFIG_MEM_ALLOC_PROFILING enabled but didn't see any issue like that.
Could you share your config file please?
Thanks,
Suren.