From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793606730; b=L9Ies6TFnaY30P7agER353rLSi/OaEcUK0qvJ8xUUw2YtY6moRk/ZPYUErhBsrBTy71+ Yau1omPVr4VaTPOFObdaGH1rYMSfWHcvnarZb9ov6rUe+/KECUgpn7I+BdgJc/B07fF/o PKPETuR58ZihLPxvqeoOSUyNmYdwjlZ8c4sZMQHEEAU+NJmQuT8zsGxlwAaqMPZXMUd1S Yf8i/7n3S6V93uMVwtfy6ZGWdSKPlYZy0CUUYh6ki1wDMNooh3g9WgdqPTsgmGkU+Sc7w cye13PtXqI1RTROKRM9yvjSHzdqkHOD9wnxHfxl0H67YKiSPyi72bmY+TIeJBqK7WZA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793606730; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=f8tivY+kihNZjwodlbKp9h20a/S7qXgwZ0Aq2zrldIs=; b=prLnC+GLNe7FRkv+zNafnCCRaKiVruMVZjgPEj8YVLpWTccS4MkHKx9eIaWSC7mb1XiL cjWRy1mD4tKNULAiBt0h65Ry0zodu7kjsgQHpNLd8JyFGdj9CKIFYyVGVQrpmZWHc2TDP ID9gQu9/aUuqltb2qKvzggryUlLXaRqIFZoTHhtaUQgjywYAQbQNS2+Dd02ot+J7l/lPt z2x8JIe7wv9SkPTX5n4kw4bwjy5uv0AWWbxatf7uoDpcrBEEtCgyrHkxFfJYNIGD92eG4 Ik8sI0/CUqjEiprwNvGO0flddsDFO1p+G1DkyTc+U5NbbBH7Q1InD8/9CSmxe1KkkEA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=XNT6m7HA; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E2B03606A32E for ; Mon, 2 Nov 2026 08:05:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=XNT6m7HA Received: by smtp.kernel.org (Postfix) with ESMTPSA id 79E7E1F000C1; Mon, 2 Nov 2026 08:05:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793606729; bh=f8tivY+kihNZjwodlbKp9h20a/S7qXgwZ0Aq2zrldIs=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=XNT6m7HAb8mZG3lcJXfFd2LLlYP1yBT59J9RxtgNPvfntIRY+jI+ch0AVdch25PTZ q7NGJsF43MpkO4yzmrS3bbTTJKSW9fIhhFoxqr91BfZuw8yYeKdW/0ildPdhCKkAtd zx4oxIt/VsN57+360Cg6j8BbaQX3ozSvLyaGH6+DKMh8+8CQ3AWvXgQFzfNBU1JtUR OUL2mf6gP/8ylwpZ8ITl8V/YvaktGjHilXOWxHq91QeCxbNyQuMeC3rRnN2lPKlWYw fBNsF6J61ZGl6C1PEDmmTvstVckQaZnklqD6aim0bqeeFuknRN73Be8CFS2H1Zkph1 Y7q40+q9BYBUQ== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH 3/6] perf/x86/intel/pt: Stop tracing at syscore shutdown Reply-To: sashiko-reviews@lists.linux.dev To: "Adrian Hunter" Cc: linux-perf-users@vger.kernel.org In-Reply-To: <20261102074039.26983-4-adrian.hunter@intel.com> References: <20261102074039.26983-1-adrian.hunter@intel.com> <20261102074039.26983-4-adrian.hunter@intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 02 Nov 2026 08:05:28 +0000 X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > Intel PT tracing can survive a shutdown sequence and continue into a > kexec'ed kernel. >=20 > The perf reboot notifier removes only per-CPU events, so per-task > events can remain active, for example: >=20 > perf record -e intel_pt// -- kexec -e >=20 > Tracing can also remain enabled on CPUs running traced tasks when > stop_other_cpus() halts them. On systems where Intel PT is unavailable > in VMX operation (IA32_VMX_MISC[14] =3D 0), VMXOFF during KVM shutdown can > re-enable TraceEn via intel_pt_handle_vmx(0) if a tracing event is > still active. >=20 > As a result, the new kernel may inherit TraceEn set and Intel PT can > [ ... ] > dmesg | grep -i 'PT is enabled at boot time' > [ 2.065889] pt: PT is enabled at boot time, doing nothing >=20 > Fixes: 52ca9ced3f70 ("perf/x86/intel/pt: Add Intel PT PMU driver") > Signed-off-by: Adrian Hunter Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261102074039.2698= 3-1-adrian.hunter@intel.com?part=3D3