From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-178.mta0.migadu.com (out-178.mta0.migadu.com [91.218.175.178]) (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 A6848309EEA for ; Wed, 26 Nov 2025 09:29:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.178 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764149367; cv=none; b=rm5PqOyPN2cgmpMF8LscIqopqS3VhkNjyevYp2VJ5DBEDkWi5PpE7pgcqpMbpp5cPvzFlR7scrUd5FgXA/pjLy5jkhzdqtjja95BeE4JSTGwieu/fIMfDLEUb6P5YTjTxACPRe+dBBhVML43FoeAD2GnD4KNJZ5elT9PffBW+5c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764149367; c=relaxed/simple; bh=GC99hb77UWnEnm28EUGHOhrCiQq3dsAhYdNfjDaBqx8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=PR1Y6QDNOg/GufAwO9pmoxq/5M50oZy+bREsTzX/srzm4Bu7EcXiyVK/9N5yG/4eQTz3+7wVjc8xY69gAFwDxThLQzfgz+nMhaGiCcWlDWv0RfQeopcLljhIodfIYNk+Y2QBa2pDm87Qa79NI4eYu5lLtAuvJNlEVDTjVLEKdSQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=iujxercK; arc=none smtp.client-ip=91.218.175.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="iujxercK" Message-ID: <7b82e322-eab7-4fc2-9de1-d10ad8251378@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1764149363; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=cyvxBUAQtvL7MLXjozd2sOG3RxdZ5x/jz3IM+iSQnko=; b=iujxercKX5myW8jvCC8bZIszUqjIHqFuuXCfZjhQ8/+ltO/GjfcaRJ6V8trg2t1uq7E7sP 8G7UBYks3QUmsLj5geyeMrer1ubOHYsgrP6jPhERvCivkZzS5lm36sZmrIBr8Xma1wRpxE gfrwCFP5qCS2u5sRXUMNVj0qC+Yb9H0= Date: Wed, 26 Nov 2025 17:29:12 +0800 Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH bpf-next v6 2/2] bpf: Hold the perf callchain entry until used completely To: Yonghong Song , peterz@infradead.org, mingo@redhat.com, acme@kernel.org, namhyung@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com, kan.liang@linux.intel.com, Andrii Nakryiko , Alexei Starovoitov , Daniel Borkmann , Eduard Zingerman , Song Liu , Martin KaFai Lau Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org References: <20251112163148.100949-1-chen.dylane@linux.dev> <20251112163148.100949-3-chen.dylane@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Tao Chen In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT 在 2025/11/14 00:01, Yonghong Song 写道: > > > On 11/12/25 8:31 AM, Tao Chen wrote: >> As Alexei noted, get_perf_callchain() return values may be reused >> if a task is preempted after the BPF program enters migrate disable >> mode. The perf_callchain_entres has a small stack of entries, and >> we can reuse it as follows: >> >> 1. get the perf callchain entry >> 2. BPF use... >> 3. put the perf callchain entry >> >> And Peter suggested that get_recursion_context used with preemption >> disabled, so we should disable preemption at BPF side. >> >> Signed-off-by: Tao Chen > > Acked-by: Yonghong Song > Hi eBPF maintainers, This patch appears to have missed the eBPF maintainers on the list, please review it again, thanks. -- Best Regards Tao Chen