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[37.188.249.12]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48397423bb4sm4170935e9.8.2026.02.17.14.05.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Feb 2026 14:05:26 -0800 (PST) From: Jiri Olsa X-Google-Original-From: Jiri Olsa Date: Tue, 17 Feb 2026 23:05:17 +0100 To: bot+bpf-ci@kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org, kafai@fb.com, eddyz87@gmail.com, songliubraving@fb.com, yhs@fb.com, menglong8.dong@gmail.com, rostedt@kernel.org, martin.lau@kernel.org, yonghong.song@linux.dev, clm@meta.com, ihor.solodrai@linux.dev Subject: Re: [RFC bpf-next 06/12] bpf: Add bpf_trampoline_multi_attach/detach functions Message-ID: References: <20260203093819.2105105-7-jolsa@kernel.org> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Feb 03, 2026 at 10:14:02AM +0000, bot+bpf-ci@kernel.org wrote: > > diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c > > index 2be2f1d0b..b76bb5450 100644 > > --- a/kernel/bpf/trampoline.c > > +++ b/kernel/bpf/trampoline.c > > [ ... ] > > > +int bpf_trampoline_multi_attach(struct bpf_prog *prog, u32 *ids, > > + struct bpf_tracing_multi_link *link) > > +{ > > + struct bpf_attach_target_info tgt_info = {}; > > + struct bpf_tracing_multi_node *mnode; > > + int j, i, err, cnt = link->nodes_cnt; > > + struct fentry_multi_data data = {}; > > + struct bpf_trampoline *tr; > > + u64 key; > > + > > + data.reg = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); > > + if (!data.reg) > > + return -ENOMEM; > > + > > + data.modify = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); > > + if (!data.modify) { > > + free_ftrace_hash(data.reg); > > + return -ENOMEM; > > + } > > + > > + for (i = 0; i < cnt; i++) { > > + mnode = &link->nodes[i]; > > + err = bpf_check_attach_target(NULL, prog, NULL, ids[i], &tgt_info); > > + if (err) > > + goto rollback_put; > > + > > + key = bpf_trampoline_compute_key(NULL, prog->aux->attach_btf, ids[i]); > > + > > + tr = bpf_trampoline_get(key, &tgt_info); > > + if (!tr) > > + goto rollback_put; > > When bpf_trampoline_get() returns NULL here, the code jumps to > rollback_put without setting err. If bpf_check_attach_target() succeeded > on this iteration (setting err to 0), the function will return 0 instead > of an error code. > > Should this be something like: > > tr = bpf_trampoline_get(key, &tgt_info); > if (!tr) { > err = -ENOMEM; > goto rollback_put; > } > yep, we should, will add, thnx jirka > > + > > + mnode->trampoline = tr; > > + mnode->node.prog = prog; > > + } > > [ ... ] > > > +rollback_put: > > + for (j = 0; j < i; j++) { > > + mnode = &link->nodes[j]; > > + bpf_trampoline_put(mnode->trampoline); > > + } > > + > > + free_fentry_multi_data(&data); > > + return err; > > +} > > > --- > AI reviewed your patch. Please fix the bug or email reply why it's not a bug. > See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md > > CI run summary: https://github.com/kernel-patches/bpf/actions/runs/21625440628 > > AI-authorship-score: low > AI-authorship-explanation: The code follows established kernel patterns and contains a human-typical oversight error (missing error assignment); the commit message has a minor copy-paste error typical of human editing. > issues-found: 1 > issue-severity-score: low > issue-severity-explanation: Missing error code when bpf_trampoline_get fails causes silent failure under memory pressure, but does not cause crashes or data corruption.