From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk1-x733.google.com (mail-qk1-x733.google.com [IPv6:2607:f8b0:4864:20::733]) by sourceware.org (Postfix) with ESMTPS id B1BA23858028 for ; Wed, 7 Apr 2021 14:20:47 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org B1BA23858028 Received: by mail-qk1-x733.google.com with SMTP id g20so18839062qkk.1 for ; Wed, 07 Apr 2021 07:20:47 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=IkcbH2adXUVlTckTvPVkKdZ0U6SZ8koQ5N+FxF2TXpc=; b=kAmb+0voQh704QyHn1Ja7yaxAPPBt/QCUERqIETe6aHlRuJ5iiaQcBM37UxXWFBI46 EXHUHBz7v/GyPETt1FZSgRfWDeco8FVgqXJPyMFAO7DPfrfSD+7u+xYdFuZiAE3nc2E7 lmubqZmy7zl26hK90Z9Nrfj228F7PtfSijXYJ/aj6TVS4DLcqARAkJS0H0qbWn5DVLsf o3EAqNwJdZcpThUpt81EJRAsSoWji09zg8qWTqu5+A4ShWYdnEcG5aulnaApG046Og2I c2lWfopHGWw7nUHeckLAPTWsE1KGoZzvTWkskQs1tJuIRkymzxRDhPpbQ3RVPTVtp+Xd uBvw== X-Gm-Message-State: AOAM532q4auHzD/JIAytXBofKx/1X0/U0b8GGU7PYVWi5B4wGLQr0h6P zpqMsuw1y6glhWkvetB/EyOj405LLMqZlJCE X-Google-Smtp-Source: ABdhPJxkC9Y3OOBp7LncAy3hAjoWtLjoilbYl2wITt1NhSBDjkWKYjUEL0HaWAbc/xJ8NyqZbZaHjg== X-Received: by 2002:a37:408:: with SMTP id 8mr3342013qke.406.1617805247123; Wed, 07 Apr 2021 07:20:47 -0700 (PDT) Received: from [192.168.1.132] ([177.194.41.149]) by smtp.gmail.com with ESMTPSA id d24sm18630388qkl.49.2021.04.07.07.20.46 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 07 Apr 2021 07:20:46 -0700 (PDT) Subject: Re: [PATCH 06/15] elf: Fix comments and logic in _dl_add_to_slotinfo To: Szabolcs Nagy Cc: libc-alpha@sourceware.org References: <068770faf123b7c227f5f1e130812f7976e74cef.1613390045.git.szabolcs.nagy@arm.com> <20210406154828.GM23289@arm.com> <20210407075735.GO23289@arm.com> From: Adhemerval Zanella Message-ID: <2a4bc996-62b5-cd2f-1124-4ed22cce62b8@linaro.org> Date: Wed, 7 Apr 2021 11:20:45 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <20210407075735.GO23289@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-6.5 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 07 Apr 2021 14:20:49 -0000 On 07/04/2021 04:57, Szabolcs Nagy wrote: > The 04/06/2021 14:47, Adhemerval Zanella wrote: >> On 06/04/2021 12:48, Szabolcs Nagy wrote: >>> The 04/02/2021 17:50, Adhemerval Zanella via Libc-alpha wrote: >>>> On 15/02/2021 08:59, Szabolcs Nagy via Libc-alpha wrote: >>>>> From: Szabolcs Nagy >>>>> >>>>> Since >>>>> >>>>> commit a509eb117fac1d764b15eba64993f4bdb63d7f3c >>>>> Avoid late dlopen failure due to scope, TLS slotinfo updates [BZ #25112] >>>>> >>>>> the generation counter update is not needed in the failure path. >>>> >>>> It is not clear to me from just the commit reference why it would >>>> be safe to remove the GL(dl_tls_generation) update on >>>> _dl_add_to_slotinfo. >>>> >>>> The dl_open_worker calls update_tls_slotinfo which in turn call >>>> might call _dl_add_to_slotinfo *after* the demarcation point. Will >>>> it terminate the process? >>> >>> in that commit the logic got changed such that allocations >>> happen before the demarcation point in resize_tls_slotinfo. >>> >>> this is the reason for the do_add bool argument in >>> _dl_add_to_slotinfo: it's called twice and the first call >>> with do_add==false is only there to ensure everything is >>> allocated before the demarcation point (so module loading >>> can be reverted, no need to bump the generation count). >>> >>> i guess this is not visible by just looking at the >>> _dl_add_to_slotinfo code. >> >> Right, so if I reading correctly once _dl_add_to_slotinfo (..., true) >> is called by update_tls_slotinfo, the malloc that create a new >> dtv_slotinfo_list won't be called (since it was already allocated >> previously) since the entry was already pre-allocated and thus the >> search part at line 978-987 will find. Is that correct? > > yes > > if you have an idea how to make things clearer let me know. > Maybe add it on the commit list. The patch looks ok to me thanks.