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 EA222C2BA83 for ; Sun, 16 Feb 2020 10:57:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C44A820857 for ; Sun, 16 Feb 2020 10:57:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728035AbgBPK5P (ORCPT ); Sun, 16 Feb 2020 05:57:15 -0500 Received: from mail-il1-f198.google.com ([209.85.166.198]:50797 "EHLO mail-il1-f198.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727800AbgBPK5O (ORCPT ); Sun, 16 Feb 2020 05:57:14 -0500 Received: by mail-il1-f198.google.com with SMTP id z12so11806050ilh.17 for ; Sun, 16 Feb 2020 02:57:12 -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:message-id:subject:from:to; bh=khkdmIgyKVi3BQRKte6m+fUbFSqCcRxt9OmDYtfZNBY=; b=DB37ZLDUBq+3Xb4RVq6AnvwZQox/9VyhnQVecEmwfahIymloP8HoBoqLZaUoSMiGES t71UFsVew9c/xEwldNjWQrZj42u20gVaCc2zviuBs3B4RNXU7e0jYlFGZVHMnB0k+rQt PovqzEAC1tNIIXV4Oa5EomQmGiCSRFXkyJLtLBVhUiE/bys721jww+NIU00K4UE05mZY K+2o4e8lfDHHzOWUxYls5xL4V8We8UZEoZk01WLvrpsIJbbCkaf+Ihn7lY+1ozZlxnGs 0YrL3qMCnNNqs34bh1fhhNQPjUqaw+auT9IbfKE+kQsmKi7eo1lQUJwBmNyZMsLBNMQ0 3ecw== X-Gm-Message-State: APjAAAUZoK6L2GgkIt6Vn4a5kKoJYnoFsnvgqvDu634Glb8W8zKfYxn3 1/blXFyydSiQm3zga2j+OR3hZxbTFWxev6qOKMrQ+oDx/iwo X-Google-Smtp-Source: APXvYqz/uhApDy8BHsTOMV0Ax4nS1NjL5q1etw2OxJWRdFvNTWSg41CD5+DRw3LUFazwsjxHOVI2b8Yuzph7xFvJnFvRpaMDOXt+ MIME-Version: 1.0 X-Received: by 2002:a92:5c8a:: with SMTP id d10mr10921125ilg.137.1581850632480; Sun, 16 Feb 2020 02:57:12 -0800 (PST) Date: Sun, 16 Feb 2020 02:57:12 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000000973ee059eaf4de6@google.com> Subject: possible deadlock in bpf_lru_push_free From: syzbot To: andriin@fb.com, ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, 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 Hello, syzbot found the following crash on: HEAD commit: 2019fc96 Merge git://git.kernel.org/pub/scm/linux/kernel/g.. git tree: net console output: https://syzkaller.appspot.com/x/log.txt?x=13aa0229e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=735296e4dd620b10 dashboard link: https://syzkaller.appspot.com/bug?extid=122b5421d14e68f29cd1 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+122b5421d14e68f29cd1@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected 5.6.0-rc1-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.3/16820 is trying to acquire lock: ffffe8ffffccc040 (&loc_l->lock){....}, at: bpf_common_lru_push_free kernel/bpf/bpf_lru_list.c:516 [inline] ffffe8ffffccc040 (&loc_l->lock){....}, at: bpf_lru_push_free+0x250/0x5b0 kernel/bpf/bpf_lru_list.c:555 but task is already holding lock: ffff88808ceda560 (&htab->buckets[i].lock#2){....}, 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: -> #2 (&htab->buckets[i].lock#2){....}: __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_lru_list_pop_free_to_local kernel/bpf/bpf_lru_list.c:340 [inline] bpf_common_lru_pop_free kernel/bpf/bpf_lru_list.c:447 [inline] bpf_lru_pop_free+0x87c/0x1670 kernel/bpf/bpf_lru_list.c:499 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 generic_map_update_batch+0x41f/0x610 kernel/bpf/syscall.c:1319 bpf_map_do_batch+0x3f5/0x510 kernel/bpf/syscall.c:3348 __do_sys_bpf+0x9b7/0x41e0 kernel/bpf/syscall.c:3460 __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 -> #1 (&l->lock){....}: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 bpf_lru_list_pop_free_to_local kernel/bpf/bpf_lru_list.c:325 [inline] bpf_common_lru_pop_free kernel/bpf/bpf_lru_list.c:447 [inline] bpf_lru_pop_free+0x67f/0x1670 kernel/bpf/bpf_lru_list.c:499 prealloc_lru_pop+0x2c/0xa0 kernel/bpf/hashtab.c:132 htab_lru_map_update_elem+0x65b/0xba0 kernel/bpf/hashtab.c:950 bpf_map_update_value.isra.0+0x61b/0x8e0 kernel/bpf/syscall.c:206 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 (&loc_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_common_lru_push_free kernel/bpf/bpf_lru_list.c:516 [inline] bpf_lru_push_free+0x250/0x5b0 kernel/bpf/bpf_lru_list.c:555 __htab_map_lookup_and_delete_batch+0x8d4/0x1540 kernel/bpf/hashtab.c:1374 htab_lru_map_lookup_and_delete_batch+0x34/0x40 kernel/bpf/hashtab.c:1491 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: Chain exists of: &loc_l->lock --> &l->lock --> &htab->buckets[i].lock#2 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&htab->buckets[i].lock#2); lock(&l->lock); lock(&htab->buckets[i].lock#2); lock(&loc_l->lock); *** DEADLOCK *** 2 locks held by syz-executor.3/16820: #0: ffffffff89bac240 (rcu_read_lock){....}, at: __htab_map_lookup_and_delete_batch+0x54b/0x1540 kernel/bpf/hashtab.c:1308 #1: ffff88808ceda560 (&htab->buckets[i].lock#2){....}, at: __htab_map_lookup_and_delete_batch+0x617/0x1540 kernel/bpf/hashtab.c:1322 stack backtrace: CPU: 0 PID: 16820 Comm: syz-executor.3 Not tainted 5.6.0-rc1-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_common_lru_push_free kernel/bpf/bpf_lru_list.c:516 [inline] bpf_lru_push_free+0x250/0x5b0 kernel/bpf/bpf_lru_list.c:555 __htab_map_lookup_and_delete_batch+0x8d4/0x1540 kernel/bpf/hashtab.c:1374 htab_lru_map_lookup_and_delete_batch+0x34/0x40 kernel/bpf/hashtab.c:1491 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: 0033:0x45c6c9 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007efeedbcdc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007efeedbce6d4 RCX: 000000000045c6c9 RDX: 0000000000000038 RSI: 00000000200001c0 RDI: 0000000000000019 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000060 R14: 00000000004c2e9b R15: 000000000076bf2c --- 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.