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 C9E514E1C6 for ; Wed, 10 Jan 2024 20:21:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Lpi5yb2P" Received: by smtp.kernel.org (Postfix) with ESMTPS id 50C70C43394 for ; Wed, 10 Jan 2024 20:21:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1704918099; bh=i2U1F3RRftz6Phbfy3DCuYl4Or5IB1O1lrTDAx07Yco=; h=From:To:Subject:Date:In-Reply-To:References:From; b=Lpi5yb2PcsYcT2Y2/7Sb947YKoxrZpSR4avrKgoskkQjyluCAsQB/pIJmx1Rjonsh KyqjJaIJ3KTAThiv52GGMTVVKJQKLAcw3GDNbzpF06UCZcHyTh4H/t502gN6ylqr8O NW5lGbhEG2bgdVzSN2GPCRU4WXck8YIsr87WPTEeqostVE406VsHbnpRxzFZwOCOPk 3Jlij9pNpp7aQILK2RqWlggAtA9atN6uermlygc1mVCJo4GMq7Zc5qZTraSsRXDGhz M6ADwbAy8/KRAQUvMDOIpzQD5vB0sHQXC3UKkW+rKU2lu4V9msHB/jpZQrxEr2ukI7 fXzl771TtFErg== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id 3AE95C53BC6; Wed, 10 Jan 2024 20:21:39 +0000 (UTC) From: bugzilla-daemon@kernel.org To: kvm@vger.kernel.org Subject: [Bug 218339] kernel goes unresponsive if single-stepping over an instruction which writes to an address for which a hardware read/write watchpoint has been set Date: Wed, 10 Jan 2024 20:21:39 +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: anthony.louis.eden@gmail.com X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: virtualization_kvm@kernel-bugs.osdl.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: 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=3D218339 --- Comment #4 from Anthony L. Eden (anthony.louis.eden@gmail.com) --- >> I tried on my side but can't reproducce it, logs below. Any steps I miss= ed ? Nope, it looks like you did everything right. I spent a little more time investigating this, since for me it's trivial to reproduce. I was able to get the guest kernel vmlinux *with* debugging information from the linux-image-6.1.0-15-amd64-dbg debian package. After entering the final `stepi` within gdb, which is when the guest goes totally unresponsive, in htop I see qemu-system-x86_64 is taking up 100% CP= U. Like I said, the thread call stacks in the qemu process look typical. I used the qemu monitor command 'dump-guest-memory -p /root/linux.core' thr= ee separate times after the guest went unresponsive, and all three of the core file backtraces look like this: #0 pv_native_set_debugreg (regno=3D7, val=3D0) at arch/x86/include/asm/debugreg.h:92 #1 0xffffffff81a21533 in set_debugreg (reg=3D7, val=3D0) at arch/x86/include/asm/paravirt.h:129 #2 local_db_save () at arch/x86/include/asm/debugreg.h:127 #3 exc_debug_kernel (dr6=3D0, regs=3D0xfffffe0000010f58) at arch/x86/kernel/traps.c:1038 #4 exc_debug (regs=3D0xfffffe0000010f58) at arch/x86/kernel/traps.c:1175 #5 0xffffffff81c00c6a in asm_exc_debug () at /build/reproducible-path/linux-6.1.66/arch/x86/include/asm/idtentry.h:606 #6 0x0000000000000000 in ?? () My VM was in a self-contained folder with its own run script on the host so= I made a tarball of it. It is available for download here (~9 GB): https://drive.google.com/file/d/1r3tlrw8kG17vFwXzP6ETv76ptNhbLYjt/view?usp= =3Dsharing Usage: $ tar xvSf deb-vm-x86_64.tar $ cd deb-vm-x86_64/ $ ./run.sh In another terminal, $ screen /dev/pts/23 115200 $ login as user 'root' with password 'root' Once inside, $ gdb /usr/bin/ls $ starti ... Oh and by the way, the version of qemu-system-x86_64 on my host is 7.2.7 (Debian 1:7.2+dfsg-7+deb12u3). --=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.=