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=-4.0 required=3.0 tests=BAYES_00,FROM_LOCAL_HEX, 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 71012C433E2 for ; Mon, 13 Jul 2020 02:24:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5B115206B6 for ; Mon, 13 Jul 2020 02:24:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728223AbgGMCYR (ORCPT ); Sun, 12 Jul 2020 22:24:17 -0400 Received: from mail-io1-f70.google.com ([209.85.166.70]:52075 "EHLO mail-io1-f70.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726267AbgGMCYQ (ORCPT ); Sun, 12 Jul 2020 22:24:16 -0400 Received: by mail-io1-f70.google.com with SMTP id l1so7160599ioh.18 for ; Sun, 12 Jul 2020 19:24:15 -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:message-id:subject:from:to; bh=oeDO3uGOlGXCY3ZqE1/B/SxjjNdp+6TXbFewQjpCefw=; b=unp9DCJdUPL42K8vrAl4IQasP0/wnokvMN9CEDLOuLgQmTFRyfRwUtFTTM/GSNeK89 sKj827vjPtR2u0EtNYogPNqNkxU80WpHDKyNnlK6Y+gBbwhRMaTlcEHEaB2X0CmjB51Z oI8zQG5gkqUu1o5MMzZEV1pd4Ph0ok2gJwvlgdHtvXF+qO+Nq/rF8NfzFvzARvegEFyr MhLJWr+XOmdpEc9LSH6j/yKdfB8KJY2urGrM+63lGhml2xTL065HnJUhvLcAgpBH9jfF WPANMoWl+6oFXH2qJW8eUnES4DqXiEaY+nWrxxGkzgJBnfre9Zo1Hoh8efvzgNKXcaPY QywA== X-Gm-Message-State: AOAM5320mhuB/ZP+c2OIZrSHkSTQW5Kt8JTqe4wQmw4HCjPnfhl8pFwE zLF6jB70HoISjrBd4DtbVY9MaSRbEq6aKT0SUCenPt8cX69m X-Google-Smtp-Source: ABdhPJxRfVkxi74W5tf9BM+cl+c0WkhO3ZD1Gj8UUT++sqELpJ0xxRFyOqGRMEVMAJfZrykDKadxtB6k6oIeE2W8sjCkgYoqqHmJ MIME-Version: 1.0 X-Received: by 2002:a02:b897:: with SMTP id p23mr7141821jam.32.1594607055648; Sun, 12 Jul 2020 19:24:15 -0700 (PDT) Date: Sun, 12 Jul 2020 19:24:15 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000001bbb6705aa49635a@google.com> Subject: KASAN: use-after-free Read in userfaultfd_release (2) From: syzbot To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Content-Type: text/plain; charset="UTF-8" Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Hello, syzbot found the following crash on: HEAD commit: 89032636 Add linux-next specific files for 20200708 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=1028732f100000 kernel config: https://syzkaller.appspot.com/x/.config?x=64a250ebabc6c320 dashboard link: https://syzkaller.appspot.com/bug?extid=75867c44841cb6373570 compiler: gcc (GCC) 10.1.0-syz 20200507 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13c4c8db100000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12cbb68f100000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+75867c44841cb6373570@syzkaller.appspotmail.com ================================================================== BUG: KASAN: use-after-free in userfaultfd_release+0x57f/0x5f0 fs/userfaultfd.c:879 Read of size 8 at addr ffff88809b09af88 by task syz-executor902/6813 CPU: 0 PID: 6813 Comm: syz-executor902 Not tainted 5.8.0-rc4-next-20200708-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+0x18f/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 userfaultfd_release+0x57f/0x5f0 fs/userfaultfd.c:879 __fput+0x33c/0x880 fs/file_table.c:281 task_work_run+0xdd/0x190 kernel/task_work.c:135 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop arch/x86/entry/common.c:239 [inline] __prepare_exit_to_usermode+0x1e9/0x1f0 arch/x86/entry/common.c:269 do_syscall_64+0x6c/0xe0 arch/x86/entry/common.c:393 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x4401f9 Code: Bad RIP value. RSP: 002b:00007ffdd722dfe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000143 RAX: ffffffffffffffe8 RBX: 00000000004002c8 RCX: 00000000004401f9 RDX: 00000000004401f9 RSI: 0000000000400aa0 RDI: 0000000000000000 RBP: 00000000006ca018 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401a00 R13: 0000000000401a90 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 6813: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 slab_post_alloc_hook mm/slab.h:536 [inline] slab_alloc mm/slab.c:3312 [inline] kmem_cache_alloc+0x148/0x550 mm/slab.c:3482 __do_sys_userfaultfd+0x96/0x4b0 fs/userfaultfd.c:2026 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 6813: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422 __cache_free mm/slab.c:3418 [inline] kmem_cache_free.part.0+0x67/0x1f0 mm/slab.c:3693 __do_sys_userfaultfd+0x3cf/0x4b0 fs/userfaultfd.c:2061 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff88809b09ae00 which belongs to the cache userfaultfd_ctx_cache of size 408 The buggy address is located 392 bytes inside of 408-byte region [ffff88809b09ae00, ffff88809b09af98) The buggy address belongs to the page: page:ffffea00026c2680 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880a03d5dc0 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffff8880a3de5d50 ffff8880a3de5d50 ffff888219701b00 raw: ffff8880a03d5dc0 ffff88809b09a000 0000000100000008 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809b09ae80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809b09af00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88809b09af80: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88809b09b000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809b09b080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches