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Groups > linux.kernel > #1343307
| From | Alexei Starovoitov <ast@fb.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH net-next 2/3] bpf: introduce BPF_MAP_TYPE_STACK_TRACE |
| Date | 2016-02-25 17:50 +0100 |
| Message-ID | <r67gZ-6Ay-3@gated-at.bofh.it> (permalink) |
| References | <r3nV0-87u-5@gated-at.bofh.it> <r3nV0-87u-13@gated-at.bofh.it> <r655w-54N-21@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 2/25/16 6:23 AM, Peter Zijlstra wrote: >> + id = hash & (smap->n_buckets - 1); > Its not at all clear where the corresponding rcu_read_lock() is at. > >> >+ bucket = rcu_dereference(smap->buckets[id]); bpf programs of all types are always executing under rcu_read_lock(). This is fundamental for maps and majority of the helpers that's why there is no WARN_ON(rcu_read_lock_held) in this helper, since we already have it in many other places. The rcu_read_lock() for kprobe type is in trace_call_bpf().
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Re: [PATCH net-next 2/3] bpf: introduce BPF_MAP_TYPE_STACK_TRACE Peter Zijlstra <peterz@infradead.org> - 2016-02-25 15:30 +0100
Re: [PATCH net-next 2/3] bpf: introduce BPF_MAP_TYPE_STACK_TRACE Alexei Starovoitov <ast@fb.com> - 2016-02-25 17:50 +0100
Re: [PATCH net-next 2/3] bpf: introduce BPF_MAP_TYPE_STACK_TRACE Peter Zijlstra <peterz@infradead.org> - 2016-02-25 18:00 +0100
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