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([2620:10d:c090:600::1:7203]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-759cb15761dsm6393291b3a.67.2025.07.21.15.39.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Jul 2025 15:39:02 -0700 (PDT) Message-ID: Subject: Re: [PATCH PATCH v2 v2 2/6] bpf: Add bpf_perf_event_aux_pause kfunc From: Eduard Zingerman To: Leo Yan , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Jiri Olsa , Ian Rogers , Adrian Hunter , KP Singh , Matt Bobrowski , Song Liu , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Yonghong Song , John Fastabend , Stanislav Fomichev , Hao Luo , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , James Clark , Suzuki K Poulose , Mike Leach Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org Date: Mon, 21 Jul 2025 15:38:59 -0700 In-Reply-To: <20250718-perf_aux_pause_resume_bpf_rebase-v2-2-992557b8fb16@arm.com> References: <20250718-perf_aux_pause_resume_bpf_rebase-v2-0-992557b8fb16@arm.com> <20250718-perf_aux_pause_resume_bpf_rebase-v2-2-992557b8fb16@arm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-1.fc42) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Fri, 2025-07-18 at 16:25 +0100, Leo Yan wrote: [...] > +__bpf_kfunc int bpf_perf_event_aux_pause(void *p__map, u64 flags, u32 pa= use) > +{ > + struct bpf_map *map =3D p__map; > + struct bpf_array *array =3D container_of(map, struct bpf_array, map); Verifier makes sure that p__map is a not null pointer to an object of type bpf_map, but it does not guarantee that the object is an instance of bpf_array. You need to check map->type, same way bpf_arena_alloc_pages() does. > + unsigned int cpu =3D smp_processor_id(); > + u64 index =3D flags & BPF_F_INDEX_MASK; > + struct bpf_event_entry *ee; > + int ret =3D 0; > + > + /* Disabling IRQ avoids race condition with perf event flows. */ > + guard(irqsave)(); > + > + if (unlikely(flags & ~(BPF_F_INDEX_MASK))) { > + ret =3D -EINVAL; > + goto out; > + } > + > + if (index =3D=3D BPF_F_CURRENT_CPU) > + index =3D cpu; > + > + if (unlikely(index >=3D array->map.max_entries)) { > + ret =3D -E2BIG; > + goto out; > + } > + > + ee =3D READ_ONCE(array->ptrs[index]); > + if (!ee) { > + ret =3D -ENOENT; > + goto out; > + } > + > + if (!has_aux(ee->event)) > + ret =3D -EINVAL; > + > + perf_event_aux_pause(ee->event, pause); > +out: > + return ret; > +} [...]