linux-kernel - Re: [PATCH v4 bpf 0/4] vmalloc: bpf: introduce VM_ALLOW_HUGE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 19 Apr 2022 19:18:50 -0700
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Alexei Starovoitov <alexei.starovoitov@...il.com>
Cc:     Mike Rapoport <rppt@...nel.org>, Song Liu <songliubraving@...com>,
        "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>,
        "mcgrof@...nel.org" <mcgrof@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "bpf@...r.kernel.org" <bpf@...r.kernel.org>,
        "hch@...radead.org" <hch@...radead.org>,
        "ast@...nel.org" <ast@...nel.org>,
        "daniel@...earbox.net" <daniel@...earbox.net>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "song@...nel.org" <song@...nel.org>,
        Kernel Team <Kernel-team@...com>,
        "pmladek@...e.com" <pmladek@...e.com>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "hpa@...or.com" <hpa@...or.com>,
        "dborkman@...hat.com" <dborkman@...hat.com>,
        "edumazet@...gle.com" <edumazet@...gle.com>,
        "bp@...en8.de" <bp@...en8.de>, "mbenes@...e.cz" <mbenes@...e.cz>,
        "imbrenda@...ux.ibm.com" <imbrenda@...ux.ibm.com>
Subject: Re: [PATCH v4 bpf 0/4] vmalloc: bpf: introduce VM_ALLOW_HUGE_VMAP

On Tue, Apr 19, 2022 at 7:03 PM Alexei Starovoitov
<alexei.starovoitov@...il.com> wrote:
>
> Here is the quote from Song's cover letter for bpf_prog_pack series:

I care about performance as much as the next person, but I care about
correctness too.

That large-page code was a disaster, and was buggy and broken.

And even with those four patches, it's still broken.

End result: there's no way that thigh gets re-enabled without the
correctness being in place.

At a minimum, to re-enable it, it needs (a) that zeroing and (b)
actual numbers on real loads. (not some artificial benchmark).

Because without (a) there's no way in hell I'll enable it.

And without (b), "performance" isn't actually an argument.

                  Linus