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 9E0623A9630 for ; Mon, 3 Aug 2026 21:02:56 +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=1785790977; cv=none; b=EB5WNJWljiBNxgHg2sCMPPmhAAuqFw8E1pdyfk5n0GUxm7XPLw1HTHP8mny9rZiGC9BEL/NMNgGLWzRyzNgrp0O//loLhSc0ekakYRWp8kyXAJJuusR1i/OfxV2Hlx8s6psCWlN7dPYQTMh0XYuy87PEOzCNwMobR1HQCS3Bw2E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785790977; c=relaxed/simple; bh=5kqDttDE1vrryg5omJVBsxs39uEJNXVWgWzg7RkiXz0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=e9TQYxKiorEviN0D2he79274HqQzb16xfK+d5ThGW3ILoq1oJE68hTx7jiwFtXzB3IhAsbTwmJ/4Vi5AkuE5N2BpovGuAmdmpFrCHlcVA3RxlDZw4Etfh89t+4coorctpZvOzJYTnuuH3Mm9Q2sFakcn7EzBX2h9EW1lJOhuEUg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AAOZnlsl; 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="AAOZnlsl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DAB211F000E9; Mon, 3 Aug 2026 21:02:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785790975; bh=tlqHmSfFg0miJAgIQG7Pn3LMAaHpm7NuX0vbHIDBeIg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=AAOZnlslgnXbXWvdfFpUU3pEwKTV2zr5lZgWT0usAHtKSHSqltWgK6LjWRGWvB42n ZRah8OwesZELAHB8O/Ah7qtUkcGH8XoC6E4IrY7NtbBX6WJHrhvvUhS4vHG+CEGgXj zxg/IuDjIvUcqtBGxMwV7Wv50ZyAh5sM17bL0dIP1VLr5v/ZIWM5Nm2pJGbTHhWNzk ixeppD+lOGuq8XjtPhA2dyHsYlyHtG/EmbcCMQyIRCBar31tGNXKDcmOa2oav7YYlX sRGQCY8gCBReHIGyMHgMR+1ljPcfdUg+q/iHbPPI/AUV72tBjw2QYsULRS0uEdZ7Xy TdIjv92YaNNfw== 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: [PATCHv3 bpf-next 06/12] bpf: Factor callchain_store function from __bpf_get_stack Date: Mon, 3 Aug 2026 23:01:43 +0200 Message-ID: <20260803210149.296496-7-jolsa@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260803210149.296496-1-jolsa@kernel.org> References: <20260803210149.296496-1-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 5b18d728f4b8..ee9905d67b8e 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -741,6 +741,29 @@ 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) @@ -753,7 +776,6 @@ 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))) @@ -798,21 +820,10 @@ 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