From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from r3-11.sinamail.sina.com.cn (r3-11.sinamail.sina.com.cn [202.108.3.11]) (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 2B6EF1F192E for ; Fri, 5 Jun 2026 21:49:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=202.108.3.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780696159; cv=none; b=XReK1DbXMQjPf7qq87En8FHdWojZSRq96/+AIHOUnLROrNBuuSaCnexYjnzMXUbD/9wHxgEjXz6G8tYZwDmZCy5PdWFbLaU/woW0cIPgdV2S6ys2UgP/4JrW+ksVSf5hsaMStdwVL/sSeYg1O24Tlx2Av9FOsR6Aj6OMIF9e0PI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780696159; c=relaxed/simple; bh=h8CkVXT51EfvOLzu/X1lIC+hXj8nDaGFdfkVy8rOQHs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tSnxcCW1et0B3Wr3mUjzEHDn/1QP0S8XK6Xj8RSs99TrC8Eg5JXNF/q6GziSYHxdxZLZnSMD1YjRg9NPNI6d9R3GZOCJU5Gr1U+BB6kwHtAmJTxdPV0cKv+gXPjpEHxuxwTA0ryMoYC1+3hcZClRBMHEbLAnYx+NCIZUHXJ6dvc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com; spf=pass smtp.mailfrom=sina.com; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b=jq7smCr5; arc=none smtp.client-ip=202.108.3.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sina.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b="jq7smCr5" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sina.com; s=201208; t=1780696155; bh=imnyB3zy2rE2KkzLvX9bXwV7Lg9bdX8zKOUKEQR9+F4=; h=From:Subject:Date:Message-ID; b=jq7smCr5WUgpj/28F9DLIRpWS+tDwm/TLOz6feoGhJ1BLsv4RYLnV4rXh0NtgaQ8k TtBFQlE8Uha6lx3nZEb8v46d4ATV1zm5EagX78TlvdlaTS/pIyxoXY9P/crmEpes0b hKbQLsqy987k0VSdAH25MvY2eop2ET4OnvwAIcyw= X-SMAIL-HELO: localhost.localdomain Received: from unknown (HELO localhost.localdomain)([114.249.62.144]) by sina.com (10.54.253.34) with ESMTP id 6A23444F00001BF0; Fri, 6 Jun 2026 05:49:05 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com Authentication-Results: sina.com; spf=none smtp.mailfrom=hdanton@sina.com; dkim=none header.i=none; dmarc=none action=none header.from=hdanton@sina.com X-SMAIL-MID: 6992856291948 X-SMAIL-UIID: AA3EEDB2B19F4785A3D69651D515F5A4-20260606-054905-1 From: Hillf Danton To: syzbot Cc: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [kvm?] [kvm-x86?] INFO: rcu detected stall in kvm_vcpu_ioctl (4) Date: Sat, 6 Jun 2026 05:48:52 +0800 Message-ID: <20260605214853.1522-1-hdanton@sina.com> In-Reply-To: <694f53ba.050a0220.35954c.0084.GAE@google.com> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit > Date: Fri, 26 Dec 2025 19:34:18 -0800 [thread overview] > Hello, > > syzbot found the following issue on: > > HEAD commit: cc3aa43b44bd Add linux-next specific files for 20251219 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=1252109a580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=f7a09bf3b9133d9d > dashboard link: https://syzkaller.appspot.com/bug?extid=3d5461510f8dc4adfe30 > compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14eb1022580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13cc18fc580000 #syz test --- x/arch/x86/kvm/hyperv.c +++ y/arch/x86/kvm/hyperv.c @@ -657,10 +657,8 @@ static int stimer_start(struct kvm_vcpu_ stimer->index, time_now, stimer->exp_time); - hrtimer_start(&stimer->timer, - ktime_add_ns(ktime_now, - 100 * (stimer->exp_time - time_now)), - HRTIMER_MODE_ABS); + hrtimer_forward_now(&stimer->timer, + ns_to_ktime(100 * (stimer->exp_time - time_now))); return 0; } stimer->exp_time = stimer->count; @@ -679,9 +677,7 @@ static int stimer_start(struct kvm_vcpu_ stimer->index, time_now, stimer->count); - hrtimer_start(&stimer->timer, - ktime_add_ns(ktime_now, 100 * (stimer->count - time_now)), - HRTIMER_MODE_ABS); + hrtimer_forward_now(&stimer->timer, ns_to_ktime(100 * (stimer->count - time_now))); return 0; } --