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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 75C1EC433E2 for ; Sun, 13 Sep 2020 19:54:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 24F6421D80 for ; Sun, 13 Sep 2020 19:54:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="P3yxDCxz"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="oOEkfTTg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725946AbgIMTyu (ORCPT ); Sun, 13 Sep 2020 15:54:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36038 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725938AbgIMTyt (ORCPT ); Sun, 13 Sep 2020 15:54:49 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 99B3BC06174A for ; Sun, 13 Sep 2020 12:54:48 -0700 (PDT) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1600026874; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=H0e4v9rcDsS5gp8nq2tqKOE7GUOY/YGmN6KNUTSD2h4=; b=P3yxDCxzoAA/yNJKB0Nh9okWR++rA9luG/4uwjYoPi696WLhbEqQz3czDf/++G23IVAmnG 2gRm33fokMOi5sUAgrruVf+ZX5mqSu9bzbaOvjb9WygcnXcuSNVp090hGh0p1XlvCK4dv5 HZu03FVVLybNsDJiB3+8KzvUrKC9tdHwo8SnH0gHxN38o2yHD6YJCXSIlnXG059tTJYpOk 5m4OzigU3ZktTx1vEXXFjJmFeOwdOCavuWKRGhmkVl+ov9kwvPIxqv9iNsPdiSsDk3VLlO SGQlNjSfQKSZ+8YeJYim2p9RBIH3rEeCXjDHXDdzK+kAhWENM4SwcfD7bj7V+A== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1600026874; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=H0e4v9rcDsS5gp8nq2tqKOE7GUOY/YGmN6KNUTSD2h4=; b=oOEkfTTg2hX0wGyOAbs9fEbpGgWS1AMrhiCR+/KFAjlvZ+aaYz9QMUO40shwde9Q+zAE9a K29zXjkIRPf/gOAQ== To: Kees Cook Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, syzbot , syzkaller-bugs@googlegroups.com, Andy Lutomirski , Peter Zijlstra Subject: Re: WARNING in syscall_exit_to_user_mode In-Reply-To: <202009121050.0D9CAB95@keescook> References: <00000000000018a47605af074c7d@google.com> <202009121050.0D9CAB95@keescook> Date: Sun, 13 Sep 2020 21:54:34 +0200 Message-ID: <87sgblpi4l.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Sep 12 2020 at 10:52, Kees Cook wrote: >> ------------[ cut here ]------------ >> syscall 56 left IRQs disabled > > This WARN appears reachable. :) The above is hardly a problem of the new entry code. It's just detecting the wreckage... > I also see on the dashboard these other problems with the new entry > code: This one is also just the messenger. That's the lockdep_assert_irqs_disabled(); in irqentry_exit() if I'm reading the reports correctly. That's a #PF returning with interrupts enabled for whatever weird reason. Let me stare at that... > https://syzkaller.appspot.com/bug?extid=d4336c84ed0099fdbe47 This one is not a new entry code problem either: > https://syzkaller.appspot.com/bug?extid=c4af95386364bc59b13e INFO: task syz-executor.0:5956 can't die for more than 143 seconds. task:syz-executor.0 state:R running task stack:25424 pid: 5956 ppid: 14284 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x8e5/0x21e0 kernel/sched/core.c:4527 preempt_schedule_irq+0xb0/0x150 kernel/sched/core.c:4785 irqentry_exit_cond_resched kernel/entry/common.c:333 [inline] irqentry_exit_cond_resched kernel/entry/common.c:325 [inline] irqentry_exit+0x65/0x90 kernel/entry/common.c:363 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:653 [inline] RIP: 0010:lock_acquire+0x27b/0xad0 kernel/locking/lockdep.c:5008 Code: 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 f8 06 00 00 48 83 3d 6a d1 5b 08 00 0f 84 a6 05 00 00 48 8b 7c 24 08 57 9d <0f> 1f 44 00 00 48 b8 00 00 00 00 00 fc ff df 48 03 44 24 10 48 c7 RSP: 0018:ffffc900088477c0 EFLAGS: 00000286 RAX: 1ffffffff136c7d9 RBX: ffff88808766c200 RCX: 000000005603e267 RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000286 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8c6a59e7 R10: fffffbfff18d4b3c R11: 0000000000000001 R12: 0000000000000002 R13: ffffffff89c67640 R14: 0000000000000000 R15: ffff88808766c200 rcu_lock_acquire include/linux/rcupdate.h:248 [inline] rcu_read_lock include/linux/rcupdate.h:641 [inline] inet_twsk_purge+0x112/0x7c0 net/ipv4/inet_timewait_sock.c:268 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:189 setup_net+0x508/0x850 net/core/net_namespace.c:364 copy_net_ns+0x31e/0x760 net/core/net_namespace.c:482 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 The new entry code is just in the stack trace because that task was preempted after a timer interrupt. Thanks, tglx