From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F2C03C433FE for ; Tue, 12 Oct 2021 16:37:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D565860E54 for ; Tue, 12 Oct 2021 16:37:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231660AbhJLQjj (ORCPT ); Tue, 12 Oct 2021 12:39:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60736 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229996AbhJLQjf (ORCPT ); Tue, 12 Oct 2021 12:39:35 -0400 Received: from mail-pg1-x52d.google.com (mail-pg1-x52d.google.com [IPv6:2607:f8b0:4864:20::52d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9FA71C061570 for ; Tue, 12 Oct 2021 09:37:33 -0700 (PDT) Received: by mail-pg1-x52d.google.com with SMTP id a73so14427415pge.0 for ; Tue, 12 Oct 2021 09:37:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=iukDYlKpdVnpmIGbLuJTC0MlapAj9Nd9mr0vNrg5C4k=; b=bZSINsLTZv0sqNMbIdtRFSEc8C+iiuq9xwnl+Y3pkNkhXbvjcYHs/GqSYFJX5yDLnh Bfm9vcs143y6w0yLCf0lmavKEGmDIyCmTmRfyNoqhjEdVmwlOt1Ss3r+QWplBdOWKNDH DoqQdn+u+7XhTaGUjt2X1hxH17v6CwwPPajjdg8TfaU8aEJtjSCA6TSV5e5XGcdHOg+h PU0SwYdHN8Yfg43hJ7/ZMZ/efDhiph5Cqfn+0V4gIK+7xdlfhGw7rvZ40AqoNzVlBmEb wOJIysxafPxoNVUYVeFWzf45JipgeLqXQgksDuatvTx8V447TJv4QaqdrGwCoe7E8Mwm GDPw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=iukDYlKpdVnpmIGbLuJTC0MlapAj9Nd9mr0vNrg5C4k=; b=GXpaTgXC4KJGbUPHxPMT7HSfgye+e63IpNblggHsDyao6HvLcQMFP5/S8y4nNwVffB ejNZMR02GQl6vZYLmhR0kmpRZ8EeP7m7HZoiXfOgZ0bqovzRsnr3FjaMrypQMYFzPxY5 vVszcjb/YkpMvU8dzfRjs0UFm0O571lAs3/xjkfVnZGVxr9QWPG8xevChTjLr8w0RCUZ B/K9cyCrWMD8t+Q0fRK92MbVfiaJCrWXhECHC+yAfgVf2KGf6/n2QbzQK3AqckcDLBcn hLFJAmQhSDrW53LH9Q5SRMXUFjSZuANYGIVA6jjHWgfcFNYIJxXUXzZX8WYiIpiCGp4I TRiA== X-Gm-Message-State: AOAM533RkW0pf6zpI/j5RT8YREgNysMKXG7DRjnaHmRAUAmbjGMyQb8P LgINIk3uoBgZdGtYwrDnL9jhTw== X-Google-Smtp-Source: ABdhPJzGtUHMC0TMXqGbLht/ed5VA30A7QH9pStPrOBeLBoX1mZYdXlF5iV7FKQ8oikd9exBMlmthQ== X-Received: by 2002:a63:204a:: with SMTP id r10mr23710980pgm.365.1634056652813; Tue, 12 Oct 2021 09:37:32 -0700 (PDT) Received: from google.com (157.214.185.35.bc.googleusercontent.com. [35.185.214.157]) by smtp.gmail.com with ESMTPSA id d67sm11428041pfd.151.2021.10.12.09.37.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Oct 2021 09:37:32 -0700 (PDT) Date: Tue, 12 Oct 2021 16:37:28 +0000 From: Sean Christopherson To: Tetsuo Handa Cc: Reiji Watanabe , Paolo Bonzini , syzkaller-bugs@googlegroups.com, linux-kernel@vger.kernel.org, syzbot Subject: Re: [syzbot] WARNING in static_key_slow_try_dec (2) Message-ID: References: <00000000000029c95905c9742a31@google.com> <611efcc8-76f7-34fc-306d-412957f81093@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 12, 2021, Sean Christopherson wrote: > On Sun, Oct 10, 2021, Tetsuo Handa wrote: > > Hello. > > > > Commit 4547700a4d190ac4 ("KVM: x86: Consolidate APIC base RESET initialization code") > > That's definitely where the error was made visible, I take that back, the bug was likely visible even before the redundant vendor code was dropped. Doesn't change the fix in any way though. > but commit 421221234ada ("KVM: x86: Open code necessary bits of > kvm_lapic_set_base() at vCPU RESET") is the real culprit. I'll send a patch > later today. I'm leaning toward a partial revert with some extra comments. > > Thanks for the debug! I was having trouble reproducing the syzbot report.