From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 78ADC12BEBB for ; Thu, 26 Sep 2024 16:37:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727368638; cv=none; b=EXy/6s0mjE9WA4O+5lRhApacIcZHBmr+qjycdPfjCI42Ptf1VfZaBRb48SAvT8N+v4RwH8cCdz2aLr7vQvG8k57fY5c7xu7g70MehUwkLWuOZKhlGq4dAf07NwwWTRUEd1Vde3l2TtPl8+mjoEeuxNCzqE7iuNjH5xW8F2SGySY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727368638; c=relaxed/simple; bh=SaSlvbC4NzBMCHuYdvdnPLP4TtU0M+fqlIs9cwZxV3I=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=mG3CxXEM5XauBW0LlbZf4V8wFKUHYby4XFRsFvt2EMxS4cXWmwtvZhBgn0TZGXTJesQt0VRB8u5rFKOkENywecURK4nog5JbEvakgme3d0/nCyAEFW3xMDT9OWhTvRw8j4A81Y8z58+K7fqUKXlSCbefKcNUivq0lrfzgbCsVbk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=casper.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=NWIwJ4ke; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=casper.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="NWIwJ4ke" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=MIME-Version:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=SaSlvbC4NzBMCHuYdvdnPLP4TtU0M+fqlIs9cwZxV3I=; b=NWIwJ4keKZT2DgiJCuu7GRcKeK rMZ0+KP6M2rSOUHC5YfUPwqQV+8Qz4FsWluRBDx0kKjAwaSraplXcyjN5TFcayAGf/u4rHk69dxh2 h+z+OdqAxUlF3pGhvJCezWM3Z44U8p3BLD9Ey9ViaAU3bIdzH0W94j8ttrECuAzOQ+UEK+lYbi5TF dwLOElq8NoCrPXJadekdRNN/ooCAFP4YHa+zGuhZrTZk1PkcfB1Aas7oIvFVzTyWGlQw1DHZ4AP+v OaeTbWhRxGFnTLlXdivl8j+WmDXI2LbLXITjqcN5aqCfAzHB7bhPg2p6jhlODT5Rm98ZPabZ5buvn ZAuJ3wOw==; Received: from [2001:8b0:10b:5:16cf:fc6a:25d9:f696] (helo=u3832b3a9db3152.ant.amazon.com) by casper.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1strUO-000000076JF-0rf9; Thu, 26 Sep 2024 16:37:13 +0000 Message-ID: Subject: Re: [PATCH v2] lockdep: add lockdep_cleanup_dead_cpu() From: David Woodhouse To: Boqun Feng Cc: Thomas Gleixner , Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long , Kent Overstreet , Arnd Bergmann , Sebastian Andrzej Siewior , linux-kernel@vger.kernel.org Date: Thu, 26 Sep 2024 17:37:12 +0100 In-Reply-To: References: Content-Type: multipart/signed; micalg="sha-256"; protocol="application/pkcs7-signature"; boundary="=-2vOE3zZUQb7P6PEGYc1M" User-Agent: Evolution 3.44.4-0ubuntu2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html --=-2vOE3zZUQb7P6PEGYc1M Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, 2024-09-26 at 09:09 -0700, Boqun Feng wrote: >=20 > I won't call this a "perfectly harmless bug", safe_halt() also contains > tracepoints, which are not supposed to work in offline path IIUC, for > example, you may incorrectly use RCU when RCU is not watching, that > could mean reading garbage memory (surely it won't crash the system, but > I hope I never need to debug such a system ;-)). >=20 > Otherwise this patch looks good to me. Thanks! Apart from the fact that I can't count. Apparently I got up to v3 of it last time, so this one should have been v4. I just mostly forgot all about it, and found it lying around in a git tree a year later, and it still seemed relevant.=20 --=-2vOE3zZUQb7P6PEGYc1M Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCEkQw ggYQMIID+KADAgECAhBNlCwQ1DvglAnFgS06KwZPMA0GCSqGSIb3DQEBDAUAMIGIMQswCQYDVQQG EwJVUzETMBEGA1UECBMKTmV3IEplcnNleTEUMBIGA1UEBxMLSmVyc2V5IENpdHkxHjAcBgNVBAoT FVRoZSBVU0VSVFJVU1QgTmV0d29yazEuMCwGA1UEAxMlVVNFUlRydXN0IFJTQSBDZXJ0aWZpY2F0 aW9uIEF1dGhvcml0eTAeFw0xODExMDIwMDAwMDBaFw0zMDEyMzEyMzU5NTlaMIGWMQswCQYDVQQG EwJHQjEbMBkGA1UECBMSR3JlYXRlciBNYW5jaGVzdGVyMRAwDgYDVQQHEwdTYWxmb3JkMRgwFgYD VQQKEw9TZWN0aWdvIExpbWl0ZWQxPjA8BgNVBAMTNVNlY3RpZ28gUlNBIENsaWVudCBBdXRoZW50 aWNhdGlvbiBhbmQgU2VjdXJlIEVtYWlsIENBMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKC AQEAyjztlApB/975Rrno1jvm2pK/KxBOqhq8gr2+JhwpKirSzZxQgT9tlC7zl6hn1fXjSo5MqXUf 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