From: Linus Torvalds <torvalds@linux-foundation.org>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"ast@kernel.org" <ast@kernel.org>, "bp@alien8.de" <bp@alien8.de>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
"daniel@iogearbox.net" <daniel@iogearbox.net>,
"dborkman@redhat.com" <dborkman@redhat.com>,
"edumazet@google.com" <edumazet@google.com>,
"hch@infradead.org" <hch@infradead.org>,
"hpa@zytor.com" <hpa@zytor.com>,
"imbrenda@linux.ibm.com" <imbrenda@linux.ibm.com>,
Kernel Team <Kernel-team@fb.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"mbenes@suse.cz" <mbenes@suse.cz>,
"mcgrof@kernel.org" <mcgrof@kernel.org>,
"pmladek@suse.com" <pmladek@suse.com>,
"Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
Mike Rapoport <rppt@kernel.org>,
"song@kernel.org" <song@kernel.org>,
Song Liu <songliubraving@fb.com>
Subject: Re: [PATCH v4 bpf 0/4] vmalloc: bpf: introduce VM_ALLOW_HUGE_VMAP
Date: Thu, 21 Apr 2022 08:44:34 -0700 [thread overview]
Message-ID: <CAHk-=wi_D0o7YLYDpW-m3HgD7HeHR45L7UYxWi2iYdc5n99P3A@mail.gmail.com> (raw)
In-Reply-To: <1650530694.evuxjgtju7.astroid@bobo.none>
On Thu, Apr 21, 2022 at 1:57 AM Nicholas Piggin <npiggin@gmail.com> wrote:
>
> Those were (AFAIKS) all in arch code though.
No Nick, they really weren't.
The bpf issue with VM_FLUSH_RESET_PERMS means that all your arguments
are invalid, because this affected non-architecture code.
So the bpf case had two independent issues: one was just bpf doing a
really bad job at making sure the executable mapping was sanely
initialized.
But the other was an actual bug in that hugepage case for vmalloc.
And that bug was an issue on power too.
So your "this is purely an x86 issue" argument is simply wrong.
Because I'm very much looking at that power code that says "oh,
__module_alloc() needs more work".
Notice?
Can these be fixed? Yes. But they can't be fixed by saying "oh, let's
disable it on x86".
Although it's probably true that at that point, some of the issues
would no longer be nearly as noticeable.
Linus
next prev parent reply other threads:[~2022-04-21 15:45 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20220415164413.2727220-1-song@kernel.org>
[not found] ` <20220415164413.2727220-2-song@kernel.org>
2022-04-15 17:43 ` [PATCH v4 bpf 1/4] vmalloc: replace VM_NO_HUGE_VMAP with VM_ALLOW_HUGE_VMAP Rik van Riel
[not found] ` <20220415164413.2727220-3-song@kernel.org>
2022-04-15 17:43 ` [PATCH v4 bpf 2/4] page_alloc: use vmalloc_huge for large system hash Rik van Riel
2022-04-25 7:07 ` Geert Uytterhoeven
2022-04-25 8:17 ` Linus Torvalds
2022-04-25 8:24 ` Geert Uytterhoeven
[not found] ` <20220415164413.2727220-4-song@kernel.org>
2022-04-15 18:06 ` [PATCH v4 bpf 3/4] module: introduce module_alloc_huge Rik van Riel
2022-06-16 16:10 ` Dave Hansen
2022-04-15 19:05 ` [PATCH v4 bpf 0/4] vmalloc: bpf: introduce VM_ALLOW_HUGE_VMAP Luis Chamberlain
2022-04-16 1:34 ` Song Liu
2022-04-16 1:42 ` Luis Chamberlain
2022-04-16 1:43 ` Luis Chamberlain
2022-04-16 5:08 ` Christoph Hellwig
2022-04-16 19:55 ` Song Liu
2022-04-16 20:30 ` Linus Torvalds
2022-04-16 22:26 ` Song Liu
2022-04-18 10:06 ` Mike Rapoport
2022-04-19 0:44 ` Luis Chamberlain
2022-04-19 1:56 ` Edgecombe, Rick P
2022-04-19 5:36 ` Song Liu
2022-04-19 18:42 ` Mike Rapoport
2022-04-19 19:20 ` Linus Torvalds
2022-04-20 2:03 ` Alexei Starovoitov
2022-04-20 2:18 ` Linus Torvalds
2022-04-20 14:42 ` Song Liu
2022-04-20 18:28 ` Luis Chamberlain
2022-04-21 3:25 ` Nicholas Piggin
2022-04-21 5:48 ` Linus Torvalds
2022-04-21 6:02 ` Linus Torvalds
2022-04-21 9:07 ` Nicholas Piggin
2022-04-21 8:57 ` Nicholas Piggin
2022-04-21 15:44 ` Linus Torvalds [this message]
2022-04-21 23:30 ` Nicholas Piggin
2022-04-22 0:49 ` Linus Torvalds
2022-04-22 1:51 ` Nicholas Piggin
2022-04-22 2:31 ` Linus Torvalds
2022-04-22 2:57 ` Nicholas Piggin
2022-04-21 15:47 ` Edgecombe, Rick P
2022-04-21 16:15 ` Linus Torvalds
2022-04-22 0:12 ` Nicholas Piggin
2022-04-22 2:29 ` Edgecombe, Rick P
2022-04-22 2:47 ` Linus Torvalds
2022-04-22 16:54 ` Edgecombe, Rick P
2022-04-22 3:08 ` Nicholas Piggin
2022-04-22 4:31 ` Nicholas Piggin
2022-04-22 17:10 ` Edgecombe, Rick P
2022-04-22 20:22 ` Edgecombe, Rick P
2022-04-22 3:33 ` Nicholas Piggin
2022-04-21 9:47 ` Nicholas Piggin
2022-04-19 21:24 ` Luis Chamberlain
2022-04-19 23:58 ` Edgecombe, Rick P
2022-04-20 7:58 ` Petr Mladek
2022-04-19 18:20 ` Mike Rapoport
2022-04-24 17:43 ` Linus Torvalds
2022-04-25 6:48 ` Song Liu
2022-04-21 3:19 ` Nicholas Piggin
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