From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-177.mta1.migadu.com (out-177.mta1.migadu.com [95.215.58.177]) (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 40B3C21CFF6 for ; Wed, 3 Dec 2025 09:34:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.177 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764754449; cv=none; b=iQ5QFXt0tip9cJVLxwaqrInUgPx0qYBCh0y51v51xviPQCgIjTsw9aOHLpl98v+c8hfh6gKWuwzKrC42adcA2gh28PlcDJZevwk8RvzteZ+lmbAIVAZA+9P5fptgSwrF3mJA3THwgcSe9c12wWoyJhJ/vagineW6DATa0boryKQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764754449; c=relaxed/simple; bh=0pUTBTrWOl8vMGRJx5bO7WE+waJ3ARqGwRgiHBOo3nQ=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=kvnLKNtFA4ocRJLxXSwkow8r8B0th9bpFWWvZc0Zj5cR5Bwd9HdiXr1j6lUsNRY/WRm1+DPokUjYVHeyU3lxKILT6pTmbudiT5wiSrcup0H5GzELNZHcYpzhvu9kKj639sgLWVusTDjoHlePRxLRfJ/g1L0zixIMtxZLMHN3ILY= 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=inK4SRCw; arc=none smtp.client-ip=95.215.58.177 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="inK4SRCw" Message-ID: <42627219-fa33-441d-b8cb-eb48ab3230d6@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1764754443; 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=ze5QiKE4t50u1X7fPBtOrmNysQ7fIpo2Qo0fD1u03Po=; b=inK4SRCwjrw64hrP/g8a9/GJoEI1Vv9gN9G74fIQeIia4xJdSo/MxKgtYqXg32Fd20jnVt YwBhbRhn9lx0T4TbPk2o3F257J3K9aRRrfEIFjPtFA25DVG7RXHqfk8+Qh4la02LT+lfMs JX+X9hRzcna6eE3xyyebb0jDPoIqLlU= Date: Wed, 3 Dec 2025 17:33:29 +0800 Precedence: bulk X-Mailing-List: linux-kernel@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 X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Tao Chen 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> <7b82e322-eab7-4fc2-9de1-d10ad8251378@linux.dev> In-Reply-To: <7b82e322-eab7-4fc2-9de1-d10ad8251378@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT 在 2025/11/26 17:29, Tao Chen 写道: > 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. > ping... -- Best Regards Tao Chen