From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 52871524AD for ; Mon, 8 Apr 2024 10:17:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712571434; cv=none; b=NuNDdrxnV1Y4+Z+1GlKV7TP//9H/7ONR8u+RGTw6IUlIuR4Gy6Qxv0njZQBNG2FhvJpGa02Xxvb2EY0KLgPN3Bbxl0UgY7HExWjSrGR7lf4tFq4Ds6EtAUeWRcPRTYM670A+CRGLflyUQ8UIOGgaaF83AKjxsVevGPZ6wDZpS00= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712571434; c=relaxed/simple; bh=fz4YeGvkKoR5kmc/E8PSurIa8ZZv5ax2hnnebm6qlHw=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=ReXbZGkDwXwI5SMQa3caIQ5FmRVXdi6CNe+/qvLkRA4FpW+ibKXAl+3Smz9Ms/75njK74ugBPMaXD5PjOin3xFL5pA69qdPzN8HWv3hBfNvA1LqBGeAJfhAzxzlhkNqOzrGjNaVU7HcqFIf8CZgU3Fq9dGWMvu++z8JB2+yhZXc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=I6UFY/A3; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="I6UFY/A3" Received: by smtp.kernel.org (Postfix) with ESMTPS id EA6EAC43394 for ; Mon, 8 Apr 2024 10:17:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1712571434; bh=fz4YeGvkKoR5kmc/E8PSurIa8ZZv5ax2hnnebm6qlHw=; h=From:To:Subject:Date:In-Reply-To:References:From; b=I6UFY/A3b3/cZroozX1XHJ+VFI5LhMh7e4DJO4WRFqf9qj8WVcJBKPQzGAC6qcV2F C4fJxYvWTXYRPW5t2UvzFfSyDbCE+WRLEGwLCXHIcLhe8kPTYx2a70pjvKAhacHlvg qEr7IRpgTYx/FsKIAVVj3a1oBXhpfjHeoWeqIUfQZ90NPOyN/kVjVtJR5qdlPtMSxF aJx/17s6ZgpPGkJpbNLRHfuELq7E03aOd8INON+Uj2Kuukl+40fg7lxEP/xuzwK5LP r7exqhkiiSMa32GdUcwch7AUNfSnloWtt1zz4538NaSnaR85vXtQvcxi146xjaZkEX NBEYycLoxSBSg== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id E0F13C53BD9; Mon, 8 Apr 2024 10:17:13 +0000 (UTC) From: bugzilla-daemon@kernel.org To: kvm@vger.kernel.org Subject: [Bug 218684] CPU soft lockups in KVM VMs on kernel 6.x after switching hypervisor from C8S to C9S Date: Mon, 08 Apr 2024 10:17:13 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: AssignedTo virtualization_kvm@kernel-bugs.osdl.org X-Bugzilla-Product: Virtualization X-Bugzilla-Component: kvm X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: frantisek@sumsal.cz X-Bugzilla-Status: RESOLVED X-Bugzilla-Resolution: PATCH_ALREADY_AVAILABLE X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: virtualization_kvm@kernel-bugs.osdl.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_status resolution Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 https://bugzilla.kernel.org/show_bug.cgi?id=3D218684 Frantisek Sumsal (frantisek@sumsal.cz) changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution|--- |PATCH_ALREADY_AVAILABLE --- Comment #2 from Frantisek Sumsal (frantisek@sumsal.cz) --- (In reply to Sean Christopherson from comment #1) > On Fri, Apr 05, 2024, bugzilla-daemon@kernel.org wrote: <...snip...> >=20 > Hmm, the vCPU is stuck in the idle HLT loop, which suggests that the vCPU > isn't > waking up when it should. But it does obviously get the hrtimer interrup= t, > so > it's not completely hosed. >=20 > Are you able to test custom kernels? If so, bisecting the host kernel is > likely > the easiest way to figure out what's going on. It might not be the > _fastest_, > but it should be straightforward, and shouldn't require much KVM expertis= e, > i.e. > won't require lengthy back-and-forth discussions if no one immediately sp= ots > a > bug. >=20 > And before bisecting, it'd be worth seeing if an upstream host kernel has= the > same problem, e.g. if upstream works, it might be easier/faster to bisect= to > a > fix, than to bisect to a bug. I did some tests over the weekend, and after installing the latest-ish main= line kernel on the host (6.9.0-0.rc1.316.vanilla.fc40.x86_64, ignore the fc40 pa= rt, I was just lazy and used [0] for a quick test) the soft lockups disappear completely. I really should've tried this before filing an issue - I tried = just 6.7.1-0.hs1.hsx.el9.x86_64 (from [1]) and that didn't help, so I mistakenly assumed that it's not the host kernel who's at fault. Also, with the mainline kernel on the host, I can now use the "stock" Arch Linux kernel on the guest as well without any soft lockups. Given the mainline kernel works as expected I'll go ahead and move this iss= ue to the RHEL downstream (and bisect the kernel to find out what's the fix). Thanks a lot for nudging me into the right direction! [0] https://fedoraproject.org/wiki/Kernel_Vanilla_Repositories [1] https://sig.centos.org/hyperscale/ --=20 You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.=