From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8569B3B3C1B for ; Wed, 29 Jul 2026 08:39:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785314352; cv=none; b=eoysj4cIXxNhsgNvZoYvsoObCS5Q4YdK/Fm8EJe/hIoePf+CUatkyqWNFVQ1bPvXnrzfCcYaczi0FarB3ARYPIaRSUVbi+WA81elGyqOTLM+dQvMIaLiuWVLk2uGR5O0+IKNMtcbYMLwMb8hL2ANF3Jr7z1Dba5RwudWDoeD9hk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785314352; c=relaxed/simple; bh=T205AUdPayribOZqBvYLnLv020WIXnd0JMgu02Y8k9c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fSrei9UgIfEI/XpP6JNvV8EOwyHK4F5h3/W2C2Tx5My1XgM3Am3KO/PQ4GLcFR3qts+anLd0uiJ0QhSwOo4rsS2z4yy7MlN7PpRyDrhr0amQ1dBhT6n0rv/cKs9LkGFnpEZsEpF1FWiXtFylnwpt01uNAY899E9GlUIhwQB/FPY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ww/ofA2I; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ww/ofA2I" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 363A61F00A3A; Wed, 29 Jul 2026 08:39:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785314351; bh=tvmt0+llmSdQHc8mLqoQ2jtu5h+fuX++KvXHTYDtMBA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Ww/ofA2IwSvCXohPhQXP9SEGjjPaqjA0pBD/W9x7gj87ufXwiP+Igj1Q6udzfPhhk ZL0ag4cfKBwKqycw6u0foqVrKg6pt+HydBZsmPj2y0DVaG4uZpKe5OZXyulbKrbWM1 I3LsOd6azTq34NgCxsvueBUQ1hITt9MGY5b8D5u2rPTM4ee45WIQtwGvD1+boDwZIv hAAlH7XVYQ1mfaFUjEtN7+5FDn0xE35PP8Sxpq8AgqmjpR9TNxGgmkBpOh7Iml6/Op njS9M4cHrsM4tYW1+QdGWo/yI7fjusYkh9OCDS03D+JxrTBoSJ0eCQdo5+BXMtB9/C /Kzd4kDDW7K6Q== From: Jiri Olsa To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: bpf@vger.kernel.org, Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , Quentin Monnet , Tao Chen , STAR Labs SG , Arnaud Lecomte Subject: [PATCHv2 bpf-next 06/11] bpf: Factor callchain_store function from __bpf_get_stack Date: Wed, 29 Jul 2026 10:38:02 +0200 Message-ID: <20260729083807.1588544-7-jolsa@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260729083807.1588544-1-jolsa@kernel.org> References: <20260729083807.1588544-1-jolsa@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The new callchain_store function stores trace entries buffer into user supplied buffer. It covers both just-ip and buildid data. Signed-off-by: Jiri Olsa --- kernel/bpf/stackmap.c | 39 +++++++++++++++++++++++++-------------- 1 file changed, 25 insertions(+), 14 deletions(-) diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index e48ddb4edd47..18b3db5c1fb9 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -746,6 +746,29 @@ const struct bpf_func_proto bpf_get_stackid_proto_pe = { .arg3_type = ARG_ANYTHING, }; +static u32 callchain_store(struct perf_callchain_entry *trace, void *buf, + u32 elem_size, u64 flags) +{ + bool user_build_id = flags & BPF_F_USER_BUILD_ID; + u32 skip = flags & BPF_F_SKIP_FIELD_MASK; + u32 trace_nr, copy_len; + u64 *ips; + + trace_nr = trace->nr - skip; + copy_len = trace_nr * elem_size; + + ips = trace->ip + skip; + if (user_build_id) { + struct bpf_stack_build_id *id_offs = buf; + + for (u32 i = 0; i < trace_nr; i++) + id_offs[i].ip = ips[i]; + } else { + memcpy(buf, ips, copy_len); + } + return trace_nr; +} + static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, struct perf_callchain_entry *trace_in, void *buf, u32 size, u64 flags, bool may_fault) @@ -758,7 +781,6 @@ static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, struct perf_callchain_entry *trace; bool kernel = !user; int err = -EINVAL; - u64 *ips; if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | BPF_F_USER_BUILD_ID))) @@ -803,21 +825,10 @@ static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, goto err_fault; } - trace_nr = trace->nr - skip; + trace_nr = callchain_store(trace, buf, elem_size, flags); copy_len = trace_nr * elem_size; - ips = trace->ip + skip; - if (user_build_id) { - struct bpf_stack_build_id *id_offs = buf; - u32 i; - - for (i = 0; i < trace_nr; i++) - id_offs[i].ip = ips[i]; - } else { - memcpy(buf, ips, copy_len); - } - - /* trace/ips should not be dereferenced after this point */ + /* trace should not be dereferenced after this point */ if (may_fault) rcu_read_unlock(); -- 2.54.0