From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ua1-f67.google.com (mail-ua1-f67.google.com [209.85.222.67]) by mx.groups.io with SMTP id smtpd.web12.1129.1590619389604359178 for ; Wed, 27 May 2020 15:43:09 -0700 Authentication-Results: mx.groups.io; dkim=pass header.i=@gmail.com header.s=20161025 header.b=cScMa/+8; spf=pass (domain: gmail.com, ip: 209.85.222.67, mailfrom: armccurdy@gmail.com) Received: by mail-ua1-f67.google.com with SMTP id g14so3317421uaq.0 for ; Wed, 27 May 2020 15:43:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ByWsITOT/lS3La83Z1/lPfZOnPH/ZmF0NfdfqEy2zFQ=; b=cScMa/+8lmqp3soiaSyCkpbeGGKwX7uN9jdaAHoF4hSSBszhzQSdy0Q7iDUwZC/1ww q+6C40U/WcO27ZLRt73L7mEl5MpMkORDBFG0xaGuWpY9PHWGcJhFKbLhBnP9c8dJPyBO Am0NySnngxx72RGVsGu9Y/E26RcY4MH0DP3NhWyE0fR3CHt8WiGc1WFdDbmFflXOyQyE t/1rfWZFNI5C/RB0iFKLqji+9x9/GPTqTtIzQIJG5sP48/IB7HJAVhHfbyUtjM41/qA9 FDBJbHLvsC8dvx01jWuze6OTaaJV6/0mHNfT0BGkFhRSEb7TKule6PDyJgiPIxm7pSHA zcOA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ByWsITOT/lS3La83Z1/lPfZOnPH/ZmF0NfdfqEy2zFQ=; b=IBL7aw6vKIuiGT+Ty/Aw9m0HirD4JDh7J2Mxfrf6hOLzD4RKgPBLc1CkGwTsGvmWHJ WATPhA468XPddDULObbPG8ELvs3JFq05CE08EfJ/a95kkyHh9hb9AE2dNAfGCWymtcrZ 71Wc+vrLp6NPLu8xqX6P+WzGRs0anIyXQyTeZj3+xDeCVwszPxY2zz5GjUgZ3hRqKiKG 1mxzESg96315I0MYhIOGJHRehL+4BJtzrpJ4RM0sRouzYWxJ0KI3mPft+a9coO1WGD3e eY8QcH0GFRrwh+MomRRn+ELjIsHeFRUc6ZtfIQPBSNxGOkoakibj6CPtrFRgMZNHfRKS 1z1w== X-Gm-Message-State: AOAM533bhWvN/J2nnCAfJaFu4LQGhjcK1mIPyBQIVzazqrf5iqsO+V2G sesNp/sNJzUfJlgD1xZNeT1xLsfIYTMcdXWKumg= X-Google-Smtp-Source: ABdhPJzjhCwudqYfb/ggr5cXbfZlpLvHmPz91JIZnUXWuU0nqDcTVcM7yFqnD0uC8u+6OXq/Z6wh4UFJxZv+DJ7GsM0= X-Received: by 2002:a9f:2788:: with SMTP id b8mr34601uab.81.1590619387849; Wed, 27 May 2020 15:43:07 -0700 (PDT) MIME-Version: 1.0 References: <20200527155011.3165976-1-raj.khem@gmail.com> <20200527155957.GK17660@denix.org> <765f3daeb6ce5f28c2d1e258dd303f5707363678.camel@linuxfoundation.org> <20200527215251.GA20867@pbcl.net> In-Reply-To: <20200527215251.GA20867@pbcl.net> From: "Andre McCurdy" Date: Wed, 27 May 2020 15:42:57 -0700 Message-ID: Subject: Re: [OE-core] [PATCH] linux-libc-headers: Check for asm/bpf_perf_event.h before multilibbing To: Phil Blundell Cc: Khem Raj , Richard Purdie , Denys Dmytriyenko , Patches and discussions about the oe-core layer Content-Type: text/plain; charset="UTF-8" On Wed, May 27, 2020 at 2:52 PM Phil Blundell via lists.openembedded.org wrote: > > On Wed, May 27, 2020 at 02:46:24PM -0700, Khem Raj wrote: > > and building userspace against way newer kernel-headers with older > > kernel underneath has unintended > > consequences. > > Can you be more specific? If this doesn't work, it's just a bug and > should be fixed. What problems are you having? I don't have an up to date example, but I've been using kernel version specific libc headers for all my projects for many years. The issue which prompted me to do that was run time crashes from libcap-ng and the historical commit message was: ---- linux-libc-headers: use 3.3.8 kernel header files for mips platforms If libcap-ng is unable to probe kernel capabilities at runtime then it will assume the kernel supports all features defined by the libc kernel headers. Since our default libc kernel headers (linux 3.14) define capabilities which are not available in linux 3.3 based stblinux kernel used for our MIPS platforms, that causes runtime crashes. As a workaround, force an older version of linux-libc-headers for all MIPS platforms to try to remove that discrepancy between the kernel's capabilities and those defined in the libc kernel headers. ---- The risk of using bleeding edge linux-libc-headers with an older kernel may be low, it's not zero. Since OE testing doesn't appear to include any coverage of older kernels, I'm not sure why I should be the guinea pig and take the risk!