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,URIBL_BLOCKED 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 7E4B4C3404C for ; Wed, 19 Feb 2020 00:37:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5926E24654 for ; Wed, 19 Feb 2020 00:37:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726840AbgBSAhO (ORCPT ); Tue, 18 Feb 2020 19:37:14 -0500 Received: from mail-il1-f200.google.com ([209.85.166.200]:39330 "EHLO mail-il1-f200.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726616AbgBSAhO (ORCPT ); Tue, 18 Feb 2020 19:37:14 -0500 Received: by mail-il1-f200.google.com with SMTP id c24so18559145ila.6 for ; Tue, 18 Feb 2020 16:37:13 -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=G0UMOdy6Hx8tmKoct5pIw4vcRna5accTPF/IPfYBhh8=; b=uF9zrzUvBbuvdbFohRjyN27rL5ehWriL0XcVx0L9K9Vj5tepWHgfu7r9F7CMyG+LH/ TX+6DpV7eMzj/rZIIaSM50UzRcpYj/q8lkhcLONd7ZVYQaNdgUkriXshPoXKLnv3nHjc 6UykGCXih0rIVrTAn3rwaiol7QB574cFJHpwRVnqqJdH1L9k/ymMGl/4tB+RoFHS+Z6T ApOctAlHECOMa6cx9rWbWomBkzv9W/LhiLMhpUj1v6hq1G/TsTUfCfY0kqe88HdwBklD MECjgcqN8h6dc/p+r/se0FffgBnMxSoLXYq2cLr9bo1A/KWx4Bb3iUV6/6qka/J1Y8Lk BTgg== X-Gm-Message-State: APjAAAUcyeAHdrpYrwNzfk7lkHS0bNifl7EHu8alPIZBARPUMExP8EHq voeW6m4PPvcEV7lv66ZMD8ezx+CEX5R41NbgGnnWVYuf1Waq X-Google-Smtp-Source: APXvYqxOg5ZusHJNKTp/6eLXbbdM4Rp9vPcRFhbcxm0I2XjrAgydk5UUE1yoPNaa6Fjw6Hh2aQjFeU4NrVNqHINA9iSJrgBj5SuJ MIME-Version: 1.0 X-Received: by 2002:a6b:e411:: with SMTP id u17mr18784050iog.39.1582072633265; Tue, 18 Feb 2020 16:37:13 -0800 (PST) Date: Tue, 18 Feb 2020 16:37:13 -0800 In-Reply-To: <0000000000000973ee059eaf4de6@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000509454059ee2fd96@google.com> Subject: Re: possible deadlock in bpf_lru_push_free From: syzbot To: andriin@fb.com, ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, hdanton@sina.com, kafai@fb.com, 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: 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: e20d3a05 bpf, offload: Replace bitwise AND by logical AND .. git tree: bpf console output: https://syzkaller.appspot.com/x/log.txt?x=1491c481e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=e7d35de59001df38 dashboard link: https://syzkaller.appspot.com/bug?extid=122b5421d14e68f29cd1 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16ca6c45e00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=134bae29e00000 Bisection is inconclusive: the first bad commit could be any of: 36a375c6 mailmap: add entry for Tiezhu Yang 95c472ff Documentation/ko_KR/howto: Update a broken link ff1e81a7 Documentation: build warnings related to missing blank lines after explicit markups has been fixed 5549c202 Documentation/ko_KR/howto: Update broken web addresses 599e6f8d Documentation: changes.rst: update several outdated project URLs 4bfdebd6 docs/locking: Fix outdated section names d1c9038a Allow git builds of Sphinx 41dcd67e Merge tag 'docs-5.6-2' of git://git.lwn.net/linux bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17c6c36ee00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+122b5421d14e68f29cd1@syzkaller.appspotmail.com IPVS: ftp: loaded support on port[0] = 21 ====================================================== WARNING: possible circular locking dependency detected 5.5.0-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor198/9748 is trying to acquire lock: ffffe8ffffc49158 (&l->lock){....}, at: bpf_lru_list_push_free kernel/bpf/bpf_lru_list.c:313 [inline] ffffe8ffffc49158 (&l->lock){....}, at: bpf_common_lru_push_free kernel/bpf/bpf_lru_list.c:532 [inline] ffffe8ffffc49158 (&l->lock){....}, at: bpf_lru_push_free+0xe5/0x5b0 kernel/bpf/bpf_lru_list.c:555 but task is already holding lock: ffff88809f6c3b60 (&htab->buckets[i].lock){....}, at: __htab_map_lookup_and_delete_batch+0x617/0x1540 kernel/bpf/hashtab.c:1322 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&htab->buckets[i].lock){....}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159 htab_lru_map_delete_node+0xce/0x2f0 kernel/bpf/hashtab.c:593 __bpf_lru_list_shrink_inactive kernel/bpf/bpf_lru_list.c:220 [inline] __bpf_lru_list_shrink+0xf9/0x470 kernel/bpf/bpf_lru_list.c:266 bpf_percpu_lru_pop_free kernel/bpf/bpf_lru_list.c:416 [inline] bpf_lru_pop_free+0xa9f/0x1670 kernel/bpf/bpf_lru_list.c:497 prealloc_lru_pop+0x2c/0xa0 kernel/bpf/hashtab.c:132 __htab_lru_percpu_map_update_elem+0x67e/0xa90 kernel/bpf/hashtab.c:1069 bpf_percpu_hash_update+0x16e/0x210 kernel/bpf/hashtab.c:1585 bpf_map_update_value.isra.0+0x2d7/0x8e0 kernel/bpf/syscall.c:181 map_update_elem kernel/bpf/syscall.c:1089 [inline] __do_sys_bpf+0x3163/0x41e0 kernel/bpf/syscall.c:3384 __se_sys_bpf kernel/bpf/syscall.c:3355 [inline] __x64_sys_bpf+0x73/0xb0 kernel/bpf/syscall.c:3355 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&l->lock){....}: check_prev_add kernel/locking/lockdep.c:2475 [inline] check_prevs_add kernel/locking/lockdep.c:2580 [inline] validate_chain kernel/locking/lockdep.c:2970 [inline] __lock_acquire+0x2596/0x4a00 kernel/locking/lockdep.c:3954 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159 bpf_lru_list_push_free kernel/bpf/bpf_lru_list.c:313 [inline] bpf_common_lru_push_free kernel/bpf/bpf_lru_list.c:532 [inline] bpf_lru_push_free+0xe5/0x5b0 kernel/bpf/bpf_lru_list.c:555 __htab_map_lookup_and_delete_batch+0x8d4/0x1540 kernel/bpf/hashtab.c:1374 htab_lru_percpu_map_lookup_and_delete_batch+0x37/0x40 kernel/bpf/hashtab.c:1474 bpf_map_do_batch+0x3f5/0x510 kernel/bpf/syscall.c:3348 __do_sys_bpf+0x1f7d/0x41e0 kernel/bpf/syscall.c:3456 __se_sys_bpf kernel/bpf/syscall.c:3355 [inline] __x64_sys_bpf+0x73/0xb0 kernel/bpf/syscall.c:3355 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&htab->buckets[i].lock); lock(&l->lock); lock(&htab->buckets[i].lock); lock(&l->lock); *** DEADLOCK *** 2 locks held by syz-executor198/9748: #0: ffffffff89bac200 (rcu_read_lock){....}, at: __htab_map_lookup_and_delete_batch+0x54b/0x1540 kernel/bpf/hashtab.c:1308 #1: ffff88809f6c3b60 (&htab->buckets[i].lock){....}, at: __htab_map_lookup_and_delete_batch+0x617/0x1540 kernel/bpf/hashtab.c:1322 stack backtrace: CPU: 0 PID: 9748 Comm: syz-executor198 Not tainted 5.5.0-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 print_circular_bug.isra.0.cold+0x163/0x172 kernel/locking/lockdep.c:1684 check_noncircular+0x32e/0x3e0 kernel/locking/lockdep.c:1808 check_prev_add kernel/locking/lockdep.c:2475 [inline] check_prevs_add kernel/locking/lockdep.c:2580 [inline] validate_chain kernel/locking/lockdep.c:2970 [inline] __lock_acquire+0x2596/0x4a00 kernel/locking/lockdep.c:3954 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:159 bpf_lru_list_push_free kernel/bpf/bpf_lru_list.c:313 [inline] bpf_common_lru_push_free kernel/bpf/bpf_lru_list.c:532 [inline] bpf_lru_push_free+0xe5/0x5b0 kernel/bpf/bpf_lru_list.c:555 __htab_map_lookup_and_delete_batch+0x8d4/0x1540 kernel/bpf/hashtab.c:1374 htab_lru_percpu_map_lookup_and_delete_batch+0x37/0x40 kernel/bpf/hashtab.c:1474 bpf_map_do_batch+0x3f5/0x510 kernel/bpf/syscall.c:3348 __do_sys_bpf+0x1f7d/0x41e0 kernel/bpf/syscall.c:3456 __se_sys_bpf kernel/bpf/syscall.c:3355 [inline] __x64_sys_bpf+0x73/0xb0 kernel/bpf/syscall.c:3355 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x440c09 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 7b 10 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fff14512e08 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00000000004a2390 RCX: 0000000000440c09 RDX: 0000000000000038 RSI: 0000000020000100 RDI: 0000000000000019 RBP: 00000000006cb018 R08: 0000000120080522 R09: 0000000120080522 R10: 0000000120080522 R11: 0000000000000246 R12: 0000000000402110 R13: 00000000004021a0 R14: 0000000000000000 R15: 0000000000000000