From: Linus Torvalds <torvalds@linux-foundation.org>
To: Andy Lutomirski <luto@amacapital.net>
Cc: "Joerg Roedel" <jroedel@suse.de>,
"Andrew Lutomirski" <luto@kernel.org>,
"Joerg Roedel" <joro@8bytes.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@kernel.org>, "Peter Anvin" <hpa@zytor.com>,
"the arch/x86 maintainers" <x86@kernel.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
"Dave Hansen" <dave.hansen@intel.com>,
"Josh Poimboeuf" <jpoimboe@redhat.com>,
"Jürgen Groß" <jgross@suse.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Borislav Petkov" <bp@alien8.de>, "Jiri Kosina" <jkosina@suse.cz>,
"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
"Brian Gerst" <brgerst@gmail.com>,
"David Laight" <David.Laight@aculab.com>,
"Denys Vlasenko" <dvlasenk@redhat.com>,
"Eduardo Valentin" <eduval@amazon.com>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Will Deacon" <will.deacon@arm.com>,
"Liguori, Anthony" <aliguori@amazon.com>,
"Daniel Gruss" <daniel.gruss@iaik.tugraz.at>,
"Hugh Dickins" <hughd@google.com>,
"Kees Cook" <keescook@google.com>,
"Andrea Arcangeli" <aarcange@redhat.com>,
"Waiman Long" <llong@redhat.com>, "Pavel Machek" <pavel@ucw.cz>,
"David H . Gutteridge" <dhgutteridge@sympatico.ca>,
"Arnaldo Carvalho de Melo" <acme@kernel.org>,
"Alexander Shishkin" <alexander.shishkin@linux.intel.com>,
"Jiri Olsa" <jolsa@redhat.com>,
"Namhyung Kim" <namhyung@kernel.org>
Subject: Re: [PATCH 1/3] perf/core: Make sure the ring-buffer is mapped in all page-tables
Date: Sat, 21 Jul 2018 14:06:52 -0700 [thread overview]
Message-ID: <CA+55aFyjFjdeAwAOu-WsE=yk_+cAaaOvp4-DSEHDaWG+1g_BSA@mail.gmail.com> (raw)
In-Reply-To: <D89602E9-E620-4AF0-822C-206D7F0BA071@amacapital.net>
On Fri, Jul 20, 2018 at 3:20 PM Andy Lutomirski <luto@amacapital.net> wrote:
> Thanks for digging! The problem was presumably that vmalloc_fault() will IRET and re-enable NMIs on the way out.
> But we’ve supported page faults on user memory in NMI handlers on 32-bit and 64-bit for quite a while, and it’s fine now.
>
> I would remove the warning, re-test, and revert the other patch.
Agreed. I don't think we have any issues with page faults during NMI
any more. Afaik the kprobe people depend on it.
That said, 64-bit mode has that scary PV-op case
(arch_flush_lazy_mmu_mode). Being PV mode, I can't find it in myself
to worry about it, I'm assuming it's ok.
Linus
next prev parent reply other threads:[~2018-07-21 21:07 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-20 16:22 [PATCH 0/3] PTI for x86-32 Fixes and Updates Joerg Roedel
2018-07-20 16:22 ` [PATCH 1/3] perf/core: Make sure the ring-buffer is mapped in all page-tables Joerg Roedel
2018-07-20 17:06 ` Andy Lutomirski
2018-07-20 17:48 ` Joerg Roedel
2018-07-20 19:32 ` Andy Lutomirski
2018-07-20 21:37 ` Joerg Roedel
2018-07-20 22:20 ` Andy Lutomirski
2018-07-21 21:06 ` Linus Torvalds [this message]
2018-07-20 19:27 ` Thomas Gleixner
2018-07-20 19:33 ` Andy Lutomirski
2018-07-20 19:43 ` Thomas Gleixner
2018-07-20 19:53 ` Thomas Gleixner
2018-07-20 16:22 ` [PATCH 2/3] x86/entry/32: Check for VM86 mode in slow-path check Joerg Roedel
2018-07-21 16:06 ` Pavel Machek
2018-07-20 16:22 ` [PATCH 3/3] x86/entry/32: Copy only ptregs on paranoid entry/exit path Joerg Roedel
2018-07-20 17:09 ` Andy Lutomirski
2018-07-20 21:42 ` Joerg Roedel
2018-07-23 3:49 ` [PATCH 0/3] PTI for x86-32 Fixes and Updates David H. Gutteridge
2018-07-23 7:29 ` Joerg Roedel
2018-07-26 3:47 ` David H. Gutteridge
2018-07-23 14:09 ` Pavel Machek
2018-07-23 19:00 ` Linus Torvalds
2018-07-23 21:38 ` Pavel Machek
2018-07-23 21:50 ` Andy Lutomirski
2018-07-23 21:55 ` Pavel Machek
2018-07-24 21:18 ` Pavel Machek
2018-07-23 21:59 ` Josh Poimboeuf
2018-07-23 22:07 ` Dave Hansen
2018-07-24 13:39 ` Pavel Machek
2018-07-24 14:39 ` Andy Lutomirski
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