From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtpout.efficios.com (smtpout.efficios.com [158.69.130.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 04E392DECBB; Wed, 20 Aug 2025 15:40:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=158.69.130.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755704457; cv=none; b=JPxBC9JwC3/H1rlTa852GMXicLP1k7+QEOWBAU3u+qNF5tkPUssJP9DjvfY+DxLQW9mPT4k8o3Me4afV1rsDXZmdpb8NGrv9UJIA1drzz+vHQAl6cOE5VgeVHse6s8guoqQBu9j/rv+m/pn1lyLK2FfhoboFF8N+2+aGbMXvXRo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755704457; c=relaxed/simple; bh=yPQP9xdUUp1NC+xPWPtOPfUaY+fSaRi9v5dh68y2WMc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=qiTyhTJbwuSv5Tp+1cpOnvXf4SHLPEeyBMYJrHetH8okgYuIChWlwDZJBdjwIIiNvufCUSKcdW0p3td4q6/Jx7SzGYdSIMJ5fYrvJd71d8kq9cC9W/X/2JbH7qbRA7yO3KIPyd9JUAlAqceJBQRavbc/AjdAKi7gYUmU5yqZISA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com; spf=pass smtp.mailfrom=efficios.com; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b=CELdqXIV; arc=none smtp.client-ip=158.69.130.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=efficios.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="CELdqXIV" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=efficios.com; s=smtpout1; t=1755704447; bh=yPQP9xdUUp1NC+xPWPtOPfUaY+fSaRi9v5dh68y2WMc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=CELdqXIVZMAhgjQeKZUVklBBaisPw93K7CNRgICRezMzZ51dofeJ207eSZ2d/cTuh 9F3a59/ol4xN8pfDNH6rVAdXqD0m3dwXcmREgRy5Z6J6YUznhmbB702nUnnWubqEZP XvStRYFrOIQDVdF3H+8xdL6FsP06pLUkVPn4w/VrR/ebzPNujUBWw6VnNlqSh+0SXe XJPHOnwlUHMKaYgr+m42kyHw6VWBT7/xA3+hEeVjNp5/5DfKY97NpkeG5FMHDQyHR7 XbAmY9H224kxvJG4TJu4kMyhekHm1T1HKzx9yabCDfjgSPq23VRLRsBJBbx3+ziPHs IsRGp/fa9O1Qg== Received: from [172.16.0.63] (192-222-132-26.qc.cable.ebox.net [192.222.132.26]) by smtpout.efficios.com (Postfix) with ESMTPSA id 4c6Vz34zxlz2G0; Wed, 20 Aug 2025 11:40:47 -0400 (EDT) Message-ID: <92cf18ee-e1ee-43ed-91e2-35e35cf97af8@efficios.com> Date: Wed, 20 Aug 2025 11:40:47 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Betterbird (Linux) Subject: Re: [PATCH] rseq/selftests: Use weak symbol reference, not definition, to link with glibc To: Mathieu Desnoyers , Sean Christopherson , Peter Zijlstra , "Paul E. McKenney" , Boqun Feng , Shuah Khan , Kienan Stewart Cc: linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Florian Weimer , Thomas Gleixner References: <20250819222945.3052711-1-seanjc@google.com> <62f49015-e1af-43ed-8499-507a49032662@efficios.com> From: Michael Jeanson Content-Language: fr Autocrypt: addr=mjeanson@efficios.com; keydata= xsFNBE0j2GkBEACcli1fPgaQ/9lCQA8xCtMmGARVfTzhyIstl41wnBdEijU6RN3EzzPc8j1i fsdK6DBEWLEoQBkFZLPmq+HJ1sNsUsJRe9OzYuetcSvDRPu8XEsLkO8akmC3fo5/Pk6iLnRb +Ge0nsNii5CSULPnHUgCxyBGcKm8hWqB4m/t79MOXHDAHNQt6ecP0ss86/vLMXpzLg9yyXBu sY1HrHMbUNssE0kqMgEmoq3v6JRwK9Qv1WDmNzl3UgMd2WZKUv0sQjyOCh/13R8Clk8Ljjnc n/RrHp6XIWreXZRTU0cL9ZfFjTntci82Je5pKWiLSaNAIHKFo8AMwvum52SqSxA76YkcNyGk 9S8O3A6tQAhZkl4rn2eF3qd1I33G+8gyvFuL8omP566rJ0PnF2hDP5FqKcbpUjs6eMWLqPYD 6AirkGurX1FmA7gg6MAiOuLptcGPYslavQK6gmcYtnjVYfueEpBzj/6jl0b3gpVYmGd/e52f mU6krF0By/Ch0Nmk3YDPuhEig4jWXmvov0BTcVFKdS7Axxh8pdZYcgz87gBgsqr90Rg7ioLB ldgI/698cXNlBWGWRvxshbEXidQF3dgksTafWylLYQVCPCHXYcVXkpoHfsEBKYKTIezT7CCA EvSDlN4X+ncIzRg5CeS3bzs4HrusiOdOjaSkVdifwQxzhvn4RQARAQABzSdNaWNoYWVsIEpl YW5zb24gPG1qZWFuc29uQGVmZmljaW9zLmNvbT7CwZQEEwEKAD4CGwMFCwkIBwMFFQoJCAsF FgIDAQACHgECF4AWIQSYZiQyQrZCJ3niC2KGVh9FIYD8/gUCZ//KEgUJHeiBpwAKCRCGVh9F IYD8/mhQD/wOShaTLm2UjDz1VwDM5l0gxfnwqG/xc69G+eDsXQoL+Ad2kc4cTKGXnkFxW/hN QMZ9dG3LeD1oqfIYSQaUC3OUZPSE07r6kH4UMkFFY6XUhBBONHD/lqGaY7FsvrPSVKo3T3GA Bc7bD/OsSgvWNyKktfxFbzm4SzO7N0ALBMC4qEaaJW68bfM/ID4Sx1gNFUFa88qghjgizfzO +4aHkxQ4MlfZ1nN0UxISlWxKt2YqfPcUdjl+8nDk0je1/6nKA9qXLBB5fbONXBGe1Bm7yiqz AlGIVJpfEKl6r74YdYzNSKuHIOAaHY5BJ5MX/0EyBAp7t6jGvt1WCqO+R3JBZnQ+/F2JFaXc aI1ay4F1ermRxcSWrxJw/XNIKNfFzgWDKceBAz+U0RUjvtDjqlZ60znh3+oAplvzkfddptQe /WDzWsCIxRnaD0aFcIiKxPc7QqkK1W60/UCjoSXDkbN4A/xa0LmiMMFJErpyRagaetQ6F13y 9oVgO7/W9ooiCTI67wymX8hBMyVZ5NttXzuNmx0TWmI29ZoBMUIaitJ8GBZI9Jxs+SpReear B0935ie2oYr3p+Dm+rGLqIbKTIrLr6o6Bc8bV/RYcMa23qXe4n67nKZJv3jU/GL3o9zobguc EoUUWe9NbBDrbi63Dz/gcGWuUSxLgpiP9i8vlGywGz/Jx87BTQRNI9hpARAAqAkuPLkp3WkX Q/aUKgHM9bVA3Qzx1lx7Cmvhpa9Rn435ciJdf0xEmv1xVwYGjsoMgStX9sb1PzBZePsJGbQ1 rW57hTkgvwqGduDPjbgVVjZ4nHYpfPzggTdm+DOpkAUvUVTRNTe4k6B8Pd/BJYu4TrBM2dLh cNakLzg3Q4rI/2AsOCOjPuRVhClILzaEttksG9KzMyFUxwVr1NAkynZLnjSQyGqKAw71DnRT vzmf3lyG1dY/DSwJyEiV8LOd1Gno6c8F6CTuow3c/J7Ttc5+9MDBiQxySwOH2Xp3ROKUtIbj Quw3cjtkTRrRknZm2EbVrB1C+KF9tAeAVNDkqfQrrdwL9Uvn9EjuHhCVsqIN+WvoJFYoIyhl HUy9uQhWQNn5G/9SNQK3BFAmJhgt64CPBIsOu3mpvMQtZHtJ8Hpfub5Uueew/MJlkYGWr1IG DjrAgDWBYSXTvqcvLpt4Yrp3RqRAsOoKKjomcFv5S0ryTQLO/aaZVTKzha41FxIhd+zUg6/r vc6RWKL+ySS1fOeFk+SaY1GeFLMoT9MgUEXHIkISC1xdA5Zri13MBxkcJkd5sZ/0C5Wlgr+f LuuzzcZX9aDiiV4uAdmy5WHVo6Y/l6MtYq+Fbzp0LSU2KemigHIGZT/gL+zDvduDIZjQZeG4 gNxM1wwsycfIYftHMfg8OVEAEQEAAcLBfAQYAQoAJgIbDBYhBJhmJDJCtkIneeILYoZWH0Uh gPz+BQJn/8o/BQkd6IGnAAoJEIZWH0UhgPz+Y3YQAJJaKODzmQMlxJ7kNTOjBo4wemDo6e5d kJ7xhYinLru+G8qJS0m7EsO51o3WtvrsPFV+RyKQrVW/Sl3m9dK/KxCWewW1itu4OKeHd+k5 UUK7xZg7lbmPFeoIaP0JtS96My0SnWRdRVSh+tQlqC4LlNIw3CiRxrCkfPlsoOBzZkTcx8Ta oYez+F0KKSH4SIk/+tgUvCAkb3JCw3kz5LxmV2NpgsvI6R5uuQ7nLtgEA6Q9g+ahICs0g+w+ HqSU1W+o6xrYZuCej1CFn3bqNuuAQGgVlD4wyS9SbXyCD5AZZwqX0V11C60AhInxCqnpn1hP qusWfhXf0BJeRNzKo7TMd3aB1YnsieNQQRopM4S8D2Embe9DtBX0WeUR/fDGjHiPItkFSel9 Gl6aXqDWDdaf1tKr4eQc845/EljpQF1LxHTp4kpGcyT5IqsA+Xom0lRowFimTwrLkHbAU+6P 3rAy/6dOzcikgkVYGln6nSgZsqeLlOyLUEE0+WpSbR4UxaMjvcM8PIx5rX6FuQxJslQ52emr 2XM0IYMuU6/5TMyTaQdS4p2nu2qu99snefOikIUzAxAp+Y5es/Tazwb83VdEGoN6JxzauDeQ upVaTHEZj/GMlMPGw05QXmB8rQz0aWTGpVBZFpmBWHYsk3QVEAOjQbjMfESW/IHw9EMZs/NH IZHa In-Reply-To: <62f49015-e1af-43ed-8499-507a49032662@efficios.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2025-08-20 08:55, Mathieu Desnoyers wrote: > > Michael, can you try it out ? Will do. > > Kienan, we may want to add a configuration forcing "-fno-common" to our > CI, this problematic pattern may be hiding other issues elsewhere. I'm > thinking of LTTng-UST tracepoint headers and libside headers. AFAIK, -fno-common has been the default since GCC 10 so it's already well tested in CI, there are a few fixes from around 2020 in LTTng related to this. > > Sean, do you want to contribute the fix to librseq as well ? Librseq currently doesn't have the weak symbols like the selftests so the fix doesn't really apply. > > Thanks everyone for looking into this. I'll be back from vacation next > week and will resume normal operations. :-) > > Mathieu > >> */ >> -__weak ptrdiff_t __rseq_offset; >> -__weak unsigned int __rseq_size; >> -__weak unsigned int __rseq_flags; >> +extern __weak ptrdiff_t __rseq_offset; >> +extern __weak unsigned int __rseq_size; >> +extern __weak unsigned int __rseq_flags; >> >> static const ptrdiff_t *libc_rseq_offset_p = &__rseq_offset; >> static const unsigned int *libc_rseq_size_p = &__rseq_size; >> @@ -209,7 +209,7 @@ void rseq_init(void) >> * libc not having registered a restartable sequence. Try to find the >> * symbols if that's the case. >> */ >> - if (!*libc_rseq_size_p) { >> + if (!libc_rseq_size_p || !*libc_rseq_size_p) { >> libc_rseq_offset_p = dlsym(RTLD_NEXT, "__rseq_offset"); >> libc_rseq_size_p = dlsym(RTLD_NEXT, "__rseq_size"); >> libc_rseq_flags_p = dlsym(RTLD_NEXT, "__rseq_flags"); >> >> base-commit: c17b750b3ad9f45f2b6f7e6f7f4679844244f0b9 > >