On Wed, Jul 30, 2025 at 4:02 PM Kees Cook <k...@kernel.org> wrote:
>
> On Thu, Jul 03, 2025 at 01:48:14PM -0700, Kumar Kartikeya Dwivedi wrote:
> > +static void bpf_prog_report_rqspinlock_violation(const char *str, void
> > *lock, bool irqsave)
> > +{
> > + struct rqspinlock_held *rqh = this_cpu_ptr(&rqspinlock_held_locks);
> > + struct bpf_stream_stage ss;
> > + struct bpf_prog *prog;
> > +
> > + prog = bpf_prog_find_from_stack();
> > + if (!prog)
> > + return;
> > + bpf_stream_stage(ss, prog, BPF_STDERR, ({
> > + bpf_stream_printk(ss, "ERROR: %s for bpf_res_spin_lock%s\n",
> > str, irqsave ? "_irqsave" : "");
> > + bpf_stream_printk(ss, "Attempted lock = 0x%px\n", lock);
> > + bpf_stream_printk(ss, "Total held locks = %d\n", rqh->cnt);
> > + for (int i = 0; i < min(RES_NR_HELD, rqh->cnt); i++)
> > + bpf_stream_printk(ss, "Held lock[%2d] = 0x%px\n", i,
> > rqh->locks[i]);
> > + bpf_stream_dump_stack(ss);
>
> Please don't include %px in stuff going back to userspace in standard
> error reporting. That's a kernel address leak:
> https://docs.kernel.org/process/deprecated.html#p-format-specifier
>
> I don't see any justification here, please remove the lock address or
> use regular %p to get a hashed value.
There is no leak here.
The prog was loaded by root and error is read by root.
