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 E32EF331EAE; Sat, 12 Sep 2026 16:19:57 +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=1789229999; cv=none; b=FjrgWHJDf59nxcu2viZc0WncUrUBbqqJUFV2BXdPmFkJB1iQLsmBWfjvQDXcFGlH8kkywlr6gUu/oG2cib8gCtFXbbH5BLapo5bBHOVtuDbKV++iu1eUBk4cyLslCP4yeLF0sQO5KzTtloU5fbHX+0/WWEQj7sFDPcb/r5vB6jc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789229999; c=relaxed/simple; bh=8O8xOp6hOdN5zXrSqhYSPpsPEu3YpkgDS/Yy1sGb00k=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=d7eTk8Mi9dfb7MK9yyi8z417BF2m3KJ7L3gFkC+aD2cr186NgSleJB0dOTCndIqr1BKP/U+5x/p6UCSncJRQQAU5903sOeNqVXPttN7EeEj/SdW+UezWP9ts4u1u/pPTTr0HWAMCoyc7EgdOFQmDfT0g1zKbr4MvrzmKzuOPPXY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xUV2YG5D; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="xUV2YG5D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2DA3B1F000FF; Sat, 12 Sep 2026 16:19:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789229997; bh=aqzYWRfD6KQk5jpxlXLF7YxENp+Lr+MX8aQ6xs1P5oM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=xUV2YG5Db/xIgrvkM9ctXsGeS59fOn4Xd8/9srSAqKKBYdD6KW46La4YyNVsKKPls yJnp3xIlmhrxD7ArX0cEnCYowUPvynQqpEPyYpVxzejiimSOI6F67+Rdo+xFDiDvx3 3pUJpqh+vMpL72GrVOYrzpNdz/jiKJiBLFQGpJnk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, James Clark , Leo Yan , Namhyung Kim , Sasha Levin Subject: [PATCH 6.1 0705/1191] perf cs-etm: Flush thread stacks after decoder reset Date: Sat, 12 Sep 2026 08:57:13 +0200 Message-ID: <20260912065604.104459724@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065548.086904252@linuxfoundation.org> References: <20260912065548.086904252@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Leo Yan [ Upstream commit ea5075e3776846d4941dddf1549426ebd3feb81f ] Perf resets the CoreSight decoder when moving to a new AUX trace buffer, this causes trace discontinunity globally. For callchain synthesis, keeping thread-stack state after decoder reset can leave stale call/return history attached to threads that are decoded later, producing incorrect synthesized callchains. Flush all host thread stacks after a decoder reset. When virtualization is present, flush the guest thread stacks as well. Reviewed-by: James Clark Signed-off-by: Leo Yan Signed-off-by: Namhyung Kim Stable-dep-of: ec99be8a31db ("perf cs-etm: Avoid truncating AUX buffer sizes to int") Signed-off-by: Sasha Levin --- tools/perf/util/cs-etm.c | 45 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 3b54baf79bd4a..361b75b0882c4 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -1635,6 +1635,45 @@ static int cs_etm__end_block(struct cs_etm_queue *etmq, return 0; } + +static int cs_etm__flush_stack_cb(struct thread *thread, + void *data __maybe_unused) +{ + thread_stack__flush(thread); + return 0; +} + +static void cs_etm__flush_machine_stack(struct cs_etm_queue *etmq, pid_t pid) +{ + struct machine *machine; + + machine = machines__find(&etmq->etm->session->machines, pid); + if (machine) + machine__for_each_thread(machine, cs_etm__flush_stack_cb, NULL); +} + +static void cs_etm__flush_all_stack(struct cs_etm_queue *etmq) +{ + enum cs_etm_pid_fmt pid_fmt = cs_etm__get_pid_fmt(etmq); + + if (!etmq->etm->synth_opts.last_branch) + return; + + switch (pid_fmt) { + case CS_ETM_PIDFMT_CTXTID2: + /* Clear the guest stack if virtualization is supported */ + cs_etm__flush_machine_stack(etmq, DEFAULT_GUEST_KERNEL_ID); + fallthrough; + case CS_ETM_PIDFMT_CTXTID: + cs_etm__flush_machine_stack(etmq, HOST_KERNEL_ID); + break; + case CS_ETM_PIDFMT_NONE: + default: + break; + + } +} + /* * cs_etm__get_data_block: Fetch a block from the auxtrace_buffer queue * if need be. @@ -1657,6 +1696,12 @@ static int cs_etm__get_data_block(struct cs_etm_queue *etmq) ret = cs_etm_decoder__reset(etmq->decoder); if (ret) return ret; + + /* + * Since the decoder is reset, this causes a global trace + * discontinuity. Flush all thread stacks. + */ + cs_etm__flush_all_stack(etmq); } return etmq->buf_len; -- 2.53.0