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 X-Spam-Level: X-Spam-Status: No, score=-5.4 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1EF5DCA9EC7 for ; Sun, 3 Nov 2019 00:27:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ED7E520663 for ; Sun, 3 Nov 2019 00:27:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727405AbfKCA1K (ORCPT ); Sat, 2 Nov 2019 20:27:10 -0400 Received: from mail-io1-f72.google.com ([209.85.166.72]:43921 "EHLO mail-io1-f72.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727350AbfKCA1K (ORCPT ); Sat, 2 Nov 2019 20:27:10 -0400 Received: by mail-io1-f72.google.com with SMTP id i2so10434665ioo.10 for ; Sat, 02 Nov 2019 17:27:09 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:in-reply-to:message-id:subject :from:to; bh=43PAAd5DFXqouo/qdBe/GRiW0b/rALk2NjJmB3iEVew=; b=A+VpDMPC4WF3C0dXH+TNtN2jHbL//LP0D84RHsoSHj0fBimuMKwnUVpzZKVPSuwziJ jBGMG72Pzs97LIBymef+hbVhMiG+t37vk5r54nAR+1Ey56YGVenJkkb/NyVzcUHgAY0j RYAuzdphiWCoPKjwyh8kkXBdo7rOJk0mkhaVvvp9RaAqZpvNUppwyvcZ1FHpd9pFjnp3 M7fUJaeQaOVtLVNshRjeas4uht69PpNgvGR/Zjm34ou0ob2tixzhL1pPlIiQcx8arfTq fIDxIuGYwFrVUTv7tvzPnuMi4l3ke83eXSrBJXdcyWJ85o+wbpjYbYaP+Ozi62zWAQcr QBNA== X-Gm-Message-State: APjAAAU9Jm3ql2mpLeAOGxF2XHwtFOrCZftZx1DzIKxUACwSvaEAHcKX En0WuQE0NDg7QOgcIpum8T1EWRIrJ1CSM2FPiPpu4G500KmN X-Google-Smtp-Source: APXvYqyFE/g8ce3eQOpNPhHAlB4bc2H196GHPApJWaZ8g2trlWRrsAZclg6hDJm52CJZ8FWwo+oSTe6B6N7+oLR7+4AtAJRjHzKx MIME-Version: 1.0 X-Received: by 2002:a92:9edd:: with SMTP id s90mr20815527ilk.244.1572740829259; Sat, 02 Nov 2019 17:27:09 -0700 (PDT) Date: Sat, 02 Nov 2019 17:27:09 -0700 In-Reply-To: <000000000000bd85b40596657dfa@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <00000000000073b15c05966642c3@google.com> Subject: Re: WARNING: suspicious RCU usage in kvm_dev_ioctl From: syzbot To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, pbonzini@redhat.com, rkrcmar@redhat.com, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org syzbot has found a reproducer for the following crash on: HEAD commit: 9d234505 Merge tag 'hwmon-for-v5.4-rc6' of git://git.kerne.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15bf068ae00000 kernel config: https://syzkaller.appspot.com/x/.config?x=cbbed3e8d4eb64bf dashboard link: https://syzkaller.appspot.com/bug?extid=75475908cd0910f141ee compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14e20268e00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15209b84e00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+75475908cd0910f141ee@syzkaller.appspotmail.com ============================= WARNING: suspicious RCU usage 5.4.0-rc5+ #0 Not tainted ----------------------------- include/linux/kvm_host.h:534 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 no locks held by syz-executor978/9604. stack backtrace: CPU: 0 PID: 9604 Comm: syz-executor978 Not tainted 5.4.0-rc5+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 lockdep_rcu_suspicious+0x153/0x15d kernel/locking/lockdep.c:5438 kvm_get_bus include/linux/kvm_host.h:534 [inline] kvm_get_bus include/linux/kvm_host.h:532 [inline] kvm_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:706 [inline] kvm_dev_ioctl_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:3444 [inline] kvm_dev_ioctl+0x100c/0x1610 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3496 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x441159 Code: e8 fc ab 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 9b 09 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffdef5e0888 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441159 RDX: 0000000000000002 RSI: 000000000000ae01 RDI: 0000000000000003 RBP: 00000000006cb018 R08: 00000000004002c8 R09: 00000000004002c8 R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000401f80 R13: 0000000000402010 R14: 0000000000000000 R15: 0000000000000000 ============================= WARNING: suspicious RCU usage 5.4.0-rc5+ #0 Not tainted ----------------------------- include/linux/kvm_host.h:629 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 no locks held by syz-executor978/9604. stack backtrace: CPU: 0 PID: 9604 Comm: syz-executor978 Not tainted 5.4.0-rc5+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 lockdep_rcu_suspicious+0x153/0x15d kernel/locking/lockdep.c:5438 __kvm_memslots include/linux/kvm_host.h:629 [inline] __kvm_memslots include/linux/kvm_host.h:626 [inline] kvm_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:708 [inline] kvm_dev_ioctl_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:3444 [inline] kvm_dev_ioctl+0x116c/0x1610 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3496 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x441159 Code: e8 fc ab 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 9b 09 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffdef5e0888 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441159 RDX: 0000000000000002 RSI: 000000000000ae01 RDI: 0000000000000003 RBP: 00000000006cb018 R08: 00000000004002c8 R09: 00000000004002c8 R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000401f80 R13: 0000000000402010 R14: 0000000000000000 R15: 0000000000000000