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=-4.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 B740FC433EF for ; Tue, 7 Sep 2021 02:30:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 92AE060E52 for ; Tue, 7 Sep 2021 02:30:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232760AbhIGCbN (ORCPT ); Mon, 6 Sep 2021 22:31:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230366AbhIGCbM (ORCPT ); Mon, 6 Sep 2021 22:31:12 -0400 Received: from mail-pj1-x102a.google.com (mail-pj1-x102a.google.com [IPv6:2607:f8b0:4864:20::102a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0E35FC061575 for ; Mon, 6 Sep 2021 19:30:07 -0700 (PDT) Received: by mail-pj1-x102a.google.com with SMTP id j10-20020a17090a94ca00b00181f17b7ef7so564503pjw.2 for ; Mon, 06 Sep 2021 19:30:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:subject:to:cc:message-id:date:user-agent:mime-version :content-transfer-encoding:content-language; bh=zl6BfDKA2Ub95iwelV68kNTqOPuhdqeFZ0nUlPUOcJM=; b=DzftnNz6qOgZYfeBcur6AuaQ4MVLbWoG+NcsoUIOh2IoDc/4yFFvrsfz3ceJdAd7Ya A3qY5pmNvbonv3Ya/LZBlErFcZd1qi4b7+C3mdwIXR8XZdPCCoFWvdGBVbNb02PnQU85 S6OxzVmp+Ncq35QYQSP73qQ2re+7/YMheM8gacr7XYUX+1TJg5VI/vh3q+M0Tq3nC07z Y2+1owEUnH5Q/hK9x+h8TA9I6ndkXpgC56eVeeOZSNMI49ZCaEFpIIrpSNkOVh/UwxOJ FzYkPzVvi8jboGvl7DQoK8vRzsiQ/IsHXLwO/pAPg+lAn2jhh9UJRz8LFmrwJWf7BjCV 3prw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:subject:to:cc:message-id:date:user-agent :mime-version:content-transfer-encoding:content-language; bh=zl6BfDKA2Ub95iwelV68kNTqOPuhdqeFZ0nUlPUOcJM=; b=ukY/7sWZw4UayEsIvcAYRliwR0EqFPo53KjP5FDoKW0hiJt3GEPJoJlFInz+MKQbJa z1GThnZtVd+YvEQDqwHbJS4dqreJCxRqCJ9hFBBVRny9JZLKoWgIvQC6iN4w+B0CagXM YkaJcQhpm/A9GQis2r8InFk9cOAW4oD2IJMcGeK37ipCmrgFSJ4XrBSsCF3v4ZnnA+j2 dJz886n/m5peYkC1hUmzWcPCIfLsNt/TAunoH6I7CC+r5Z6EsFXkDVom0pvA8DLE6qGA hEnB6rhaJDtbeBDKR9kN5KRxW411J+s4IExdGRnJgRysng24NaW6OEDEyUH/BKkDUrSh r72w== X-Gm-Message-State: AOAM5324aU1jnJ7UHePHyZnd9jL+tUsAojxrtpjUqMKozZbh6ilERRS/ IPNsOEEWC30/pvgCwRQKFyZcA+XK7CA= X-Google-Smtp-Source: ABdhPJx7v/nAinHF9sgOga2v+1NM3gLVKWPJ/cpDtclaa9HVBT1JATEfYboXU8526GljLF1gfRotVw== X-Received: by 2002:a17:902:be0f:b0:13a:19b6:6870 with SMTP id r15-20020a170902be0f00b0013a19b66870mr8997920pls.64.1630981806161; Mon, 06 Sep 2021 19:30:06 -0700 (PDT) Received: from [166.111.139.135] ([166.111.139.135]) by smtp.gmail.com with ESMTPSA id o2sm11266323pgc.47.2021.09.06.19.30.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 06 Sep 2021 19:30:05 -0700 (PDT) From: Jia-Ju Bai Subject: [BUG] android: possible ABBA deadlock in print_binder_proc() and binder_get_txn_from_and_acq_inner() To: Greg KH , arve@android.com, tkjos@android.com, maco@android.com, joel@joelfernandes.org, christian@brauner.io, hridya@google.com, surenb@google.com Cc: linux-kernel Message-ID: <303401d0-25c9-d04b-e96d-3ca2aa0a616d@gmail.com> Date: Tue, 7 Sep 2021 10:29:57 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, My static analysis tool reports a possible ABBA deadlock in the android driver in Linux 5.10: print_binder_proc()   binder_inner_proc_lock()     _binder_inner_proc_lock()       spin_lock(&proc->inner_lock); --> Line 662 (Lock A)   print_binder_thread_ilocked()     print_binder_transaction_ilocked()       spin_lock(&t->lock); --> Line 5531 (Lock B) binder_get_txn_from_and_acq_inner()   binder_get_txn_from()     spin_lock(&t->lock); --> Line 1833 (Lock B)   binder_inner_proc_lock()     _binder_inner_proc_lock()       spin_lock(&proc->inner_lock); --> Line 662 (Lock A) When print_binder_proc() and binder_get_txn_from_and_acq_inner() are concurrently executed, the deadlock can occur. I am not quite sure whether this possible deadlock is real and how to fix it if it is real. Any feedback would be appreciated, thanks :) Reported-by: TOTE Robot Best wishes, Jia-Ju Bai