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=-8.7 required=3.0 tests=BAYES_00,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 08511C433E7 for ; Fri, 28 Aug 2020 04:57:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D7A1E20848 for ; Fri, 28 Aug 2020 04:57:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726762AbgH1E50 (ORCPT ); Fri, 28 Aug 2020 00:57:26 -0400 Received: from mail-il1-f198.google.com ([209.85.166.198]:38841 "EHLO mail-il1-f198.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726643AbgH1E5Y (ORCPT ); Fri, 28 Aug 2020 00:57:24 -0400 Received: by mail-il1-f198.google.com with SMTP id m10so5985609ild.5 for ; Thu, 27 Aug 2020 21:57:23 -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=LgE6lJVanO3aGKaU5BWBpevjqiZZr3WyVWUmT2Inr0A=; b=TM2Z0zqscsV/GaZ4Dt9V7d/hqV9FhyUKlDO+nIvFmtKLOVO3wi4nspoKcWyY5YraRJ Neho9TfWid8luIRtHNqWu4G05ozsjXZrHS/jF9sPIsTqgtgGysH6BZptw/p7QGnknyN0 erg2WI+o9vG04565GGl28n5Y5iWMH5xvOCMA5VJ+5L91hbCkpd/NWIVErBsZ5Nq1bO6B qqtVlB7JOqXTs13fkpKRrmL6C26h47Pqi65sy6/Sl0XjB2kKSHNwkb7aExQvEdQ85eWf wSW7GXS8VUC6qKI9bWf+dtHl8hTqUiz+FFif329cMEiS6mr68/6LsXQGl1ypAO2HSFk9 z9eg== X-Gm-Message-State: AOAM531k6uESkk1GjAioNiHeDwxjwOlFskdPc5XrE6RgpUX/Ec+EsyRU jBCzN7yg//+sD4nr+BVZZuEvIuUONowAgOAoCfllMp5goSsc X-Google-Smtp-Source: ABdhPJwKGzJ7FC5EKbQvsE+s6PZQaLMlOkbNO8nAsujnHSQAjsejY52S4LjLBvgweGEUdjRBw22KfUgimGzK/DJ+P2Mk7VFhXuCJ MIME-Version: 1.0 X-Received: by 2002:a5e:a512:: with SMTP id 18mr10756972iog.128.1598590642511; Thu, 27 Aug 2020 21:57:22 -0700 (PDT) Date: Thu, 27 Aug 2020 21:57:22 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <00000000000063640c05ade8e3de@google.com> Subject: possible deadlock in proc_pid_syscall (2) From: syzbot To: adobriyan@gmail.com, akpm@linux-foundation.org, avagin@gmail.com, christian@brauner.io, ebiederm@xmission.com, gladkov.alexey@gmail.com, keescook@chromium.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, walken@google.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 issue on: HEAD commit: 15bc20c6 Merge tag 'tty-5.9-rc3' of git://git.kernel.org/p.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15349f96900000 kernel config: https://syzkaller.appspot.com/x/.config?x=978db74cb30aa994 dashboard link: https://syzkaller.appspot.com/bug?extid=db9cdf3dd1f64252c6ef compiler: gcc (GCC) 10.1.0-syz 20200507 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+db9cdf3dd1f64252c6ef@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected 5.9.0-rc2-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/18445 is trying to acquire lock: ffff88809f2e0dc8 (&sig->exec_update_mutex){+.+.}-{3:3}, at: lock_trace fs/proc/base.c:408 [inline] ffff88809f2e0dc8 (&sig->exec_update_mutex){+.+.}-{3:3}, at: proc_pid_syscall+0xaa/0x2b0 fs/proc/base.c:646 but task is already holding lock: ffff88808e9a3c30 (&p->lock){+.+.}-{3:3}, at: seq_read+0x61/0x1070 fs/seq_file.c:155 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:956 [inline] __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103 seq_read+0x61/0x1070 fs/seq_file.c:155 pde_read fs/proc/inode.c:306 [inline] proc_reg_read+0x221/0x300 fs/proc/inode.c:318 do_loop_readv_writev fs/read_write.c:734 [inline] do_loop_readv_writev fs/read_write.c:721 [inline] do_iter_read+0x48e/0x6e0 fs/read_write.c:955 vfs_readv+0xe5/0x150 fs/read_write.c:1073 kernel_readv fs/splice.c:355 [inline] default_file_splice_read.constprop.0+0x4e6/0x9e0 fs/splice.c:412 do_splice_to+0x137/0x170 fs/splice.c:871 splice_direct_to_actor+0x307/0x980 fs/splice.c:950 do_splice_direct+0x1b3/0x280 fs/splice.c:1059 do_sendfile+0x55f/0xd40 fs/read_write.c:1540 __do_sys_sendfile64 fs/read_write.c:1601 [inline] __se_sys_sendfile64 fs/read_write.c:1587 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1587 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (sb_writers#4){.+.+}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write+0x234/0x470 fs/super.c:1672 sb_start_write include/linux/fs.h:1643 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:354 ovl_setattr+0x5c/0x850 fs/overlayfs/inode.c:28 notify_change+0xb60/0x10a0 fs/attr.c:336 chown_common+0x4a9/0x550 fs/open.c:674 do_fchownat+0x126/0x1e0 fs/open.c:704 __do_sys_lchown fs/open.c:729 [inline] __se_sys_lchown fs/open.c:727 [inline] __x64_sys_lchown+0x7a/0xc0 fs/open.c:727 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}: down_read+0x96/0x420 kernel/locking/rwsem.c:1492 inode_lock_shared include/linux/fs.h:789 [inline] lookup_slow fs/namei.c:1560 [inline] walk_component+0x409/0x6a0 fs/namei.c:1860 lookup_last fs/namei.c:2309 [inline] path_lookupat+0x1ba/0x830 fs/namei.c:2333 filename_lookup+0x19f/0x560 fs/namei.c:2366 create_local_trace_uprobe+0x87/0x4e0 kernel/trace/trace_uprobe.c:1574 perf_uprobe_init+0x132/0x210 kernel/trace/trace_event_perf.c:323 perf_uprobe_event_init+0xff/0x1c0 kernel/events/core.c:9580 perf_try_init_event+0x12a/0x560 kernel/events/core.c:10899 perf_init_event kernel/events/core.c:10951 [inline] perf_event_alloc.part.0+0xdee/0x3770 kernel/events/core.c:11229 perf_event_alloc kernel/events/core.c:11608 [inline] __do_sys_perf_event_open+0x72c/0x2cb0 kernel/events/core.c:11724 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&sig->exec_update_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:2496 [inline] check_prevs_add kernel/locking/lockdep.c:2601 [inline] validate_chain kernel/locking/lockdep.c:3218 [inline] __lock_acquire+0x2a6b/0x5640 kernel/locking/lockdep.c:4426 lock_acquire+0x1f1/0xad0 kernel/locking/lockdep.c:5005 __mutex_lock_common kernel/locking/mutex.c:956 [inline] __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103 lock_trace fs/proc/base.c:408 [inline] proc_pid_syscall+0xaa/0x2b0 fs/proc/base.c:646 proc_single_show+0x116/0x1e0 fs/proc/base.c:775 seq_read+0x432/0x1070 fs/seq_file.c:208 do_loop_readv_writev fs/read_write.c:734 [inline] do_loop_readv_writev fs/read_write.c:721 [inline] do_iter_read+0x48e/0x6e0 fs/read_write.c:955 vfs_readv+0xe5/0x150 fs/read_write.c:1073 do_preadv fs/read_write.c:1165 [inline] __do_sys_preadv fs/read_write.c:1215 [inline] __se_sys_preadv fs/read_write.c:1210 [inline] __x64_sys_preadv+0x231/0x310 fs/read_write.c:1210 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: &sig->exec_update_mutex --> sb_writers#4 --> &p->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&p->lock); lock(sb_writers#4); lock(&p->lock); lock(&sig->exec_update_mutex); *** DEADLOCK *** 1 lock held by syz-executor.0/18445: #0: ffff88808e9a3c30 (&p->lock){+.+.}-{3:3}, at: seq_read+0x61/0x1070 fs/seq_file.c:155 stack backtrace: CPU: 0 PID: 18445 Comm: syz-executor.0 Not tainted 5.9.0-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+0x18f/0x20d lib/dump_stack.c:118 check_noncircular+0x324/0x3e0 kernel/locking/lockdep.c:1827 check_prev_add kernel/locking/lockdep.c:2496 [inline] check_prevs_add kernel/locking/lockdep.c:2601 [inline] validate_chain kernel/locking/lockdep.c:3218 [inline] __lock_acquire+0x2a6b/0x5640 kernel/locking/lockdep.c:4426 lock_acquire+0x1f1/0xad0 kernel/locking/lockdep.c:5005 __mutex_lock_common kernel/locking/mutex.c:956 [inline] __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103 lock_trace fs/proc/base.c:408 [inline] proc_pid_syscall+0xaa/0x2b0 fs/proc/base.c:646 proc_single_show+0x116/0x1e0 fs/proc/base.c:775 seq_read+0x432/0x1070 fs/seq_file.c:208 do_loop_readv_writev fs/read_write.c:734 [inline] do_loop_readv_writev fs/read_write.c:721 [inline] do_iter_read+0x48e/0x6e0 fs/read_write.c:955 vfs_readv+0xe5/0x150 fs/read_write.c:1073 do_preadv fs/read_write.c:1165 [inline] __do_sys_preadv fs/read_write.c:1215 [inline] __se_sys_preadv fs/read_write.c:1210 [inline] __x64_sys_preadv+0x231/0x310 fs/read_write.c:1210 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d5b9 Code: 5d b4 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 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fb613f9ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 0000000000025740 RCX: 000000000045d5b9 RDX: 0000000000000333 RSI: 00000000200017c0 RDI: 0000000000000006 RBP: 000000000118cf90 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffe2a82bbbf R14: 00007fb613f9f9c0 R15: 000000000118cf4c --- This report is generated by a bot. 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