From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yb1-xb2a.google.com (mail-yb1-xb2a.google.com [IPv6:2607:f8b0:4864:20::b2a]) by sourceware.org (Postfix) with ESMTPS id CF2963858D28 for ; Tue, 14 Dec 2021 09:09:51 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org CF2963858D28 Received: by mail-yb1-xb2a.google.com with SMTP id e136so44623783ybc.4 for ; Tue, 14 Dec 2021 01:09:51 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=l5DHEuPMHBCgqn7G6SH/YuaJ0kika52qQBhG7ol+aPg=; b=w4OUp8L+Q/SvXH1UkRbuAotDJgEnJVRIgmedQ8xDXnccDujNsweyGWdk6TUnSy6/3p 2Dbui9rkhOIqM+4gxFtv3H/bpYhkic4XUDr9DS6h6i9hGqBPzMjyqLAsmeKmmt2FtDmQ EryTqMmcqKFFDL0F5XCVjJnkk6W44lJN3m0HtU+J+q9Bf+Q2jO7P40lkOqZC+AJPdMbu 9kgE1cDg8ezazVRDP/0Tvtn9tS7SQamBbCmvErWv/Z/vv6SOsYRsYoW+GDz/NwV5osmZ T/yQLeqU0n6YPWHzMI5INlFZkzkWHXd0jFe8wEx7q5traNoqTTPZIGB8tGm+9wFEBoiP YdwQ== X-Gm-Message-State: AOAM530LGS652ldwWoaXOo2ZSTUNtpyc1isdTZ4EVBqeUK2O1UsFHbgn AaAh9kHkGaI+0VJ8g10AMpkcPXdVEnu5LTKQrOx1Zg== X-Google-Smtp-Source: ABdhPJzXVn7gFKEZderUjTpPQK5DdUSZNqDTzyBZwFL4VGHmjq33r279QuWkW/q/VTGJGDXqJVhdI9a2qc9d511gtok= X-Received: by 2002:a25:d04d:: with SMTP id h74mr4554140ybg.266.1639472991222; Tue, 14 Dec 2021 01:09:51 -0800 (PST) MIME-Version: 1.0 References: <20211119150329.2200675-1-adhemerval.zanella@linaro.org> <87bl1tmtxz.fsf@oldenburg.str.redhat.com> <873a6969-8c06-5233-2b4c-48360e120f07@linaro.org> <877dchlbb8.fsf@oldenburg.str.redhat.com> <6386c389-086d-e123-d4d6-a97777f207ed@linaro.org> <87czm8quz3.fsf@oldenburg.str.redhat.com> <871r2nmmaf.fsf@oldenburg.str.redhat.com> <20211214001742.lbleuljd2dgmfinx@google.com> <87sfuvsgll.fsf@oldenburg.str.redhat.com> In-Reply-To: <87sfuvsgll.fsf@oldenburg.str.redhat.com> From: =?UTF-8?B?RsSBbmctcnXDrCBTw7JuZw==?= Date: Tue, 14 Dec 2021 01:09:40 -0800 Message-ID: Subject: Re: [PATCH] elf: Add elf checks for main executable To: Florian Weimer Cc: Adhemerval Zanella , GNU C Library Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-17.9 required=5.0 tests=BAYES_00, DKIMWL_WL_MED, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, ENV_AND_HDR_SPF_MATCH, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, USER_IN_DEF_DKIM_WL, USER_IN_DEF_SPF_WL autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) 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: Tue, 14 Dec 2021 09:09:53 -0000 On Tue, Dec 14, 2021 at 1:03 AM Florian Weimer wrote: > > * F=C4=81ng-ru=C3=AC S=C3=B2ng: > > > If the question is: "if upstream glibc implements the diagnostic, will > > ChromeOS port the patch to their glibc". My reply is non-authoritative= , > > but if this has not been a problem for more than 3 years now, I do know > > see large value backporting the feature to their older glibc release. > > But if you don't backport, you can teach your toolchain to start > producing binaries that fail to load on older glibc. You will have to > keep creating binaries that lack proper markup. > > My concern is that we go through all this trouble to implement a version > proper handshake, and yet Google binaries will still crash on older > glibc. 3+ years ago, "still crash on older glibc" was considered an acceptable compromise as the scenario (cared by some upstream glibc folks) is simply unsupported (and by many other groups). Now after 3 years, (while this is unsupported) back porting RELR executables to less-than-3 year old ChromeOS would still work because all glibc releases in the past 3 years support RELR. If you consider symbol versioning, many symbols get new symbols which won't run on 3-year-old glibc anyway.