Messages in this thread | | | From | Kees Cook <> | Date | Thu, 7 Jun 2018 12:13:49 -0700 | Subject | Re: nfp: bpf: perf event output helpers support |
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On Thu, Jun 7, 2018 at 9:33 AM, Jakub Kicinski <jakub.kicinski@netronome.com> wrote: > On Wed, 6 Jun 2018 22:15:04 -0700, Kees Cook wrote: >> > + rcu_read_lock(); >> > + if (!rhashtable_lookup_fast(&bpf->maps_neutral, &map, >> > + nfp_bpf_maps_neutral_params)) { >> > + rcu_read_unlock(); >> > + pr_warn("perf event: dest map pointer %px not recognized, dropping event\n", >> > + map); >> >> Please don't use %px on kernel pointers unless you absolutely have >> to[1]. It seems like this value wouldn't be actionable here, so likely >> it's best to just remove its use entirely. > > We're using kernel pointer as an opaque handle when communicating with > the device. We need the actual value to correlate things. Maybe I used > the %px slightly out of spite there, because I forgot %p is now useless > and wasted half an hour on debugging an endian issue :S > > This message can only really trigger when root loads a specific BPF map > onto the device and FW is buggy. Can I fix it in -next? I'm making > changes to this part of the code anyway.
That'd be fine by me, thanks!
-Kees
-- Kees Cook Pixel Security
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