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=unavailable 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 6C7EBC432C0 for ; Sun, 1 Dec 2019 04:37:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 496862073C for ; Sun, 1 Dec 2019 04:37:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727401AbfLAEhL (ORCPT ); Sat, 30 Nov 2019 23:37:11 -0500 Received: from mail-il1-f197.google.com ([209.85.166.197]:34655 "EHLO mail-il1-f197.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727280AbfLAEhL (ORCPT ); Sat, 30 Nov 2019 23:37:11 -0500 Received: by mail-il1-f197.google.com with SMTP id l13so12820976ils.1 for ; Sat, 30 Nov 2019 20:37:09 -0800 (PST) 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=v0J+wZhdjttjLui7Jcw+Ref517WIdIELo1N/ZGyLXOw=; b=Suib5YiK2UWTqW0vsx7PT3biY51/Si66BVvVNhIEoLrV09Ng4038A/ZyeOIWzMi9tG rlQPvvTg3ecIJmLtGg3kU18ly5T8lR8QaB7hO6pNrF3SI/9BakJJDfbMf/ETFID4oQoA fIUfnDljVTW9mRcrke/LW5qv9EQH2TJ/q3dkkpb7XR5GMf11j9NGi7CTcYuKwY0PLrge z/LGN1cJkG/kAQQYvr8vu+DOVQK8hAR2Dl1AlQOIcQ0GIN6/Sko4yJmmskUVmdkKm4wR n6OMAPipkdCMZFJzfVrgNpG8/uWOk4D1VAXr7DWFbgKeO9plmDclhuAEJCbDuPmJ5g6B kA/w== X-Gm-Message-State: APjAAAXQn2n2JW8+S8fCMBGgvwfK9juu6Unisyo88VWsKol9+uq3q0WJ DSVudkqpbsfSJColeFU3ptdawO1zmeyZvuxZuMk7q/VSxkvp X-Google-Smtp-Source: APXvYqz0NKRcLrMe23S+IgpLnyHyGusKwopVSgltulCHh7AwK0zzMEf5PqkLdvDDVKefcs6DPg+9gp54mQSoam2BvSHaG7Ylmyz+ MIME-Version: 1.0 X-Received: by 2002:a5d:9dd9:: with SMTP id 25mr37351873ioo.287.1575175029112; Sat, 30 Nov 2019 20:37:09 -0800 (PST) Date: Sat, 30 Nov 2019 20:37:09 -0800 In-Reply-To: <0000000000007cace40598282858@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <00000000000011c9b105989d0489@google.com> Subject: Re: WARNING: refcount bug in smc_release (2) From: syzbot To: davem@davemloft.net, kgraul@linux.ibm.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com, ubraun@linux.ibm.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org syzbot has found a reproducer for the following crash on: HEAD commit: 32ef9553 Merge tag 'fsnotify_for_v5.5-rc1' of git://git.ke.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15f6d82ae00000 kernel config: https://syzkaller.appspot.com/x/.config?x=ff560c3de405258c dashboard link: https://syzkaller.appspot.com/bug?extid=96d3f9ff6a86d37e44c8 compiler: gcc (GCC) 9.0.0 20181231 (experimental) userspace arch: i386 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14b57336e00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=149e357ae00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+96d3f9ff6a86d37e44c8@syzkaller.appspotmail.com ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 9807 at lib/refcount.c:28 refcount_warn_saturate+0x1dc/0x1f0 lib/refcount.c:28 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 9807 Comm: syz-executor293 Not tainted 5.4.0-syzkaller #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+0x197/0x210 lib/dump_stack.c:118 panic+0x2e3/0x75c kernel/panic.c:221 __warn.cold+0x2f/0x3e kernel/panic.c:582 report_bug+0x289/0x300 lib/bug.c:195 fixup_bug arch/x86/kernel/traps.c:174 [inline] fixup_bug arch/x86/kernel/traps.c:169 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027 RIP: 0010:refcount_warn_saturate+0x1dc/0x1f0 lib/refcount.c:28 Code: e9 d8 fe ff ff 48 89 df e8 c1 5a 24 fe e9 85 fe ff ff e8 e7 08 e7 fd 48 c7 c7 a0 6f 4f 88 c6 05 60 b8 a4 06 01 e8 53 bd b7 fd <0f> 0b e9 ac fe ff ff 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 55 48 RSP: 0018:ffff888093c97998 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff815e4316 RDI: ffffed1012792f25 RBP: ffff888093c979a8 R08: ffff8880a04d4380 R09: ffffed1015d26621 R10: ffffed1015d26620 R11: ffff8880ae933107 R12: 0000000000000003 R13: 0000000000000000 R14: ffff8880a118d380 R15: ffff88809427e558 refcount_sub_and_test include/linux/refcount.h:261 [inline] refcount_dec_and_test include/linux/refcount.h:281 [inline] sock_put include/net/sock.h:1728 [inline] smc_release+0x445/0x520 net/smc/af_smc.c:202 __sock_release+0xce/0x280 net/socket.c:591 sock_close+0x1e/0x30 net/socket.c:1269 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x8e7/0x2ef0 kernel/exit.c:797 do_group_exit+0x135/0x360 kernel/exit.c:895 get_signal+0x47c/0x24f0 kernel/signal.c:2734 do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815 exit_to_usermode_loop+0x286/0x380 arch/x86/entry/common.c:160 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath arch/x86/entry/common.c:278 [inline] do_syscall_32_irqs_on arch/x86/entry/common.c:352 [inline] do_fast_syscall_32+0xbbd/0xe16 arch/x86/entry/common.c:408 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f69a39 Code: Bad RIP value. RSP: 002b:00000000f7f441ec EFLAGS: 00000296 ORIG_RAX: 00000000000000f0 RAX: fffffffffffffe00 RBX: 00000000080fb018 RCX: 0000000000000080 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 0000000020000040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Kernel Offset: disabled Rebooting in 86400 seconds..