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=-0.4 required=3.0 tests=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 95DFEC8300A for ; Thu, 30 Apr 2020 09:39:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6C1A820838 for ; Thu, 30 Apr 2020 09:39:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726789AbgD3JjP (ORCPT ); Thu, 30 Apr 2020 05:39:15 -0400 Received: from mail-il1-f198.google.com ([209.85.166.198]:54559 "EHLO mail-il1-f198.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726127AbgD3JjO (ORCPT ); Thu, 30 Apr 2020 05:39:14 -0400 Received: by mail-il1-f198.google.com with SMTP id e68so667775ilg.21 for ; Thu, 30 Apr 2020 02:39:13 -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=vIIPXuZlrFp+xo9o1bYGQn743Cw7J0PFty6YB+csSAs=; b=SDjc7dxQes0YK3uDoyyvSPhZIvTRflKeKihdP4zzPNkMwkG0r1wwk++gw5kbFAYL1J tTG8bhU6GqJ1F9L6zXnAOuCOBDjrP9sswe5DUZchG3GOJJdupCUY7ECIbPnYQtPMGrHp ZSkF/sM33JQe5W86CUcWl3Ya88491RgLHBAJwQSRyePWl+fTp+iiFgHIRZcCCxb1zv+i Nn1STCCAijYTM7O5M0bYF10lvJJJ2AfGlv6piUAnCxgHvvBF7u1xiXokKHoGnm2FM5n/ slKEyDFtA/X/G4u66ivYu9uUjlU+m/6igG+aq3k/xXBgMOPoBNvAL1iCvk5z2tHUAeSu Ww/Q== X-Gm-Message-State: AGi0PuY+cAyAJDXkbQWR4Fs1P+BAOF7fXz36IRoKo6APmMXDKm5qE4Cs dxMcQmp8vlmM0v7soPHi1mIBxAlUConUjpcg4Odmv0lXWVBB X-Google-Smtp-Source: APiQypKKYdthYXw0O5GkI1I7af5y5d0o9AL7tkFs1a//unSQ2oRtOdcpPA8GxmMlfAy2fOhW3czeZfzNNjviHCduO1HO2K9C6QZP MIME-Version: 1.0 X-Received: by 2002:a5d:96c5:: with SMTP id r5mr936809iol.41.1588239553493; Thu, 30 Apr 2020 02:39:13 -0700 (PDT) Date: Thu, 30 Apr 2020 02:39:13 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000006780dc05a47ed632@google.com> Subject: KASAN: use-after-free Write in bpf_link_put From: syzbot To: andriin@fb.com, ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, kafai@fb.com, kpsingh@chromium.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, songliubraving@fb.com, syzkaller-bugs@googlegroups.com, yhs@fb.com Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, syzbot found the following crash on: HEAD commit: 449e14bf bpf: Fix unused variable warning git tree: bpf-next console output: https://syzkaller.appspot.com/x/log.txt?x=109eb5f8100000 kernel config: https://syzkaller.appspot.com/x/.config?x=16d87c420507d444 dashboard link: https://syzkaller.appspot.com/bug?extid=39b64425f91b5aab714d compiler: gcc (GCC) 9.0.0 20181231 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+39b64425f91b5aab714d@syzkaller.appspotmail.com ================================================================== BUG: KASAN: use-after-free in atomic64_dec_and_test include/asm-generic/atomic-instrumented.h:1557 [inline] BUG: KASAN: use-after-free in bpf_link_put+0x19/0x1b0 kernel/bpf/syscall.c:2255 Write of size 8 at addr ffff8880a7248800 by task syz-executor.0/28011 CPU: 0 PID: 28011 Comm: syz-executor.0 Not tainted 5.7.0-rc2-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+0x188/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd3/0x315 mm/kasan/report.c:382 __kasan_report.cold+0x35/0x4d mm/kasan/report.c:511 kasan_report+0x33/0x50 mm/kasan/common.c:625 check_memory_region_inline mm/kasan/generic.c:187 [inline] check_memory_region+0x141/0x190 mm/kasan/generic.c:193 atomic64_dec_and_test include/asm-generic/atomic-instrumented.h:1557 [inline] bpf_link_put+0x19/0x1b0 kernel/bpf/syscall.c:2255 bpf_link_release+0x33/0x40 kernel/bpf/syscall.c:2270 __fput+0x33e/0x880 fs/file_table.c:280 task_work_run+0xf4/0x1b0 kernel/task_work.c:123 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x2fa/0x360 arch/x86/entry/common.c:165 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x6b1/0x7d0 arch/x86/entry/common.c:305 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x7fc891a66469 Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 8b 0d ff 49 2b 00 f7 d8 64 89 01 48 RSP: 002b:00007fc892156db8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: fffffffffffffff4 RBX: 000000000042c4e0 RCX: 00007fc891a66469 RDX: 0000000000000010 RSI: 0000000020000040 RDI: 000000000000001c RBP: 00000000006abf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005 R13: 000000000000004f R14: 0000000000415473 R15: 00007fc8921575c0 Allocated by task 28011: save_stack+0x1b/0x40 mm/kasan/common.c:49 set_track mm/kasan/common.c:57 [inline] __kasan_kmalloc mm/kasan/common.c:495 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:468 kmem_cache_alloc_trace+0x153/0x7d0 mm/slab.c:3551 kmalloc include/linux/slab.h:555 [inline] kzalloc include/linux/slab.h:669 [inline] cgroup_bpf_link_attach+0x13d/0x5b0 kernel/bpf/cgroup.c:894 link_create kernel/bpf/syscall.c:3765 [inline] __do_sys_bpf+0x238c/0x46d0 kernel/bpf/syscall.c:3987 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 Freed by task 28011: save_stack+0x1b/0x40 mm/kasan/common.c:49 set_track mm/kasan/common.c:57 [inline] kasan_set_free_info mm/kasan/common.c:317 [inline] __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:456 __cache_free mm/slab.c:3426 [inline] kfree+0x109/0x2b0 mm/slab.c:3757 cgroup_bpf_link_attach+0x2bc/0x5b0 kernel/bpf/cgroup.c:906 link_create kernel/bpf/syscall.c:3765 [inline] __do_sys_bpf+0x238c/0x46d0 kernel/bpf/syscall.c:3987 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 The buggy address belongs to the object at ffff8880a7248800 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 0 bytes inside of 128-byte region [ffff8880a7248800, ffff8880a7248880) The buggy address belongs to the page: page:ffffea00029c9200 refcount:1 mapcount:0 mapping:00000000a3d4ec31 index:0xffff8880a7248700 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea00024ceac8 ffffea000251d3c8 ffff8880aa000700 raw: ffff8880a7248700 ffff8880a7248000 000000010000000f 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a7248700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a7248780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880a7248800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a7248880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a7248900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================== --- 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.