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Date:   Wed, 25 May 2022 08:01:42 +0200
From:   "hch@lst.de" <hch@lst.de>
To:     Luis Chamberlain <mcgrof@kernel.org>
Cc:     "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        "hch@lst.de" <hch@lst.de>, "dave@stgolabs.net" <dave@stgolabs.net>,
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        Adam Manzanares <a.manzanares@samsung.com>
Subject: Re: [PATCH v3 bpf-next 5/8] bpf: use module_alloc_huge for
 bpf_prog_pack
Message-ID: <20220525060142.GB10762@lst.de>
References: <20220520031548.338934-1-song@kernel.org> <20220520031548.338934-6-song@kernel.org> <Yog5yXqAQZAmpgCD@bombadil.infradead.org> <17c6110273d59e3fdeea3338abefac03951ff404.camel@intel.com> <YolGU5JGE9NVrrrc@bombadil.infradead.org> <a634037bb023973b8263a65b93fa73a7a5c0dc52.camel@intel.com> <Yo1XTN441qbNTLGR@bombadil.infradead.org>
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On Tue, May 24, 2022 at 03:08:12PM -0700, Luis Chamberlain wrote:
> > A rename seems good to me. Module space is really just dynamically
> > allocated text space now. There used to be a vmalloc_exec() that
> > allocated text in vmalloc space, 
> 
> Yes I saw that but it was generic and it did not do the arch-specific
> override, and so that is why Christoph ripped it out and open coded
> it on the only user, on module_alloc().

It it also because random code does not have any business allocating
executable memory.  Executable memory in kernel is basically for
modules and module-like code like eBPF, and no one else has any business
allocating pages with the execute bit set (or the NX bit not set).