From: David Miller <davem@davemloft.net>
To: jannh@google.com
Cc: alexei.starovoitov@gmail.com, torvalds@linux-foundation.org,
mhiramat@kernel.org, rostedt@goodmis.org, luto@amacapital.net,
linux-kernel@vger.kernel.org, mingo@kernel.org,
akpm@linux-foundation.org, stable@vger.kernel.org,
changbin.du@gmail.com, keescook@chromium.org, luto@kernel.org,
daniel@iogearbox.net, netdev@vger.kernel.org,
bpf@vger.kernel.org
Subject: Re: [PATCH 1/2 v2] kprobe: Do not use uaccess functions to access kernel memory that can fault
Date: Fri, 22 Feb 2019 15:16:06 -0800 (PST) [thread overview]
Message-ID: <20190222.151606.344940961752699587.davem@davemloft.net> (raw)
In-Reply-To: <CAG48ez0nMEMP5-eSFWmLKs30zApgZ57zqU1Od9cROBYQvoJxsg@mail.gmail.com>
From: Jann Horn <jannh@google.com>
Date: Sat, 23 Feb 2019 00:11:58 +0100
> I think what Linus is saying is: There are some scenarios (like a
> system with the old 4G/4G X86 patch) where *the same* address can
> refer to two different pieces of memory, depending on whether you
> interpret it as a kernel pointer or a user pointer.
Exactly.
On sparc64 the kernel is mapped exactly at the same virtual addresses
as userspace processes usually are mapped, even 32-bit ones. The
difference is the MMU context only.
next prev parent reply other threads:[~2019-02-22 23:16 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAHk-=wgJzNp0R3cVhjBPHTR4X9sOvHdqK4UVFfbsOKQ6L=A_eQ@mail.gmail.com>
[not found] ` <CAHk-=wh9XrOykA5J9RQ7zaBio-S_D+1AE+rGnBYWSd==pCXh+w@mail.gmail.com>
[not found] ` <20190219111802.1d6dbaa3@gandalf.local.home>
[not found] ` <CAHk-=wgTuK3kAduP-gr10vykT1uG=B2VpdffvmyBuTQ1UxPpMg@mail.gmail.com>
[not found] ` <20190219140330.5dd9e876@gandalf.local.home>
[not found] ` <20190220171019.5e81a4946b56982f324f7c45@kernel.org>
[not found] ` <20190220094926.0ab575b3@gandalf.local.home>
[not found] ` <20190222172745.2c7205d62003c0a858e33278@kernel.org>
[not found] ` <20190222173509.88489b7c5d1bf0e2ec2382ee@kernel.org>
[not found] ` <CAHk-=whNf_n1WXWW+ugAVeL5ZK0GcEP3cTYocju1nS85VtMjjQ@mail.gmail.com>
2019-02-22 19:27 ` [PATCH 1/2 v2] kprobe: Do not use uaccess functions to access kernel memory that can fault Alexei Starovoitov
2019-02-22 19:30 ` Steven Rostedt
2019-02-22 19:34 ` Alexei Starovoitov
2019-02-22 19:39 ` Steven Rostedt
2019-02-22 19:55 ` Andy Lutomirski
2019-02-22 21:43 ` Jann Horn
2019-02-22 22:08 ` Nadav Amit
2019-02-22 22:17 ` Jann Horn
2019-02-22 22:21 ` Nadav Amit
2019-02-22 22:39 ` Nadav Amit
2019-02-22 23:02 ` Jann Horn
2019-02-22 23:22 ` Nadav Amit
2019-02-22 23:59 ` Andy Lutomirski
2019-02-23 0:03 ` Alexei Starovoitov
2019-02-23 0:15 ` Nadav Amit
2019-02-24 19:35 ` Andy Lutomirski
2019-02-25 13:36 ` Masami Hiramatsu
2019-02-22 21:20 ` Linus Torvalds
2019-02-22 21:38 ` David Miller
2019-02-22 21:59 ` Linus Torvalds
2019-02-22 22:51 ` Alexei Starovoitov
2019-02-22 23:11 ` Jann Horn
2019-02-22 23:16 ` David Miller [this message]
2019-02-22 23:16 ` Linus Torvalds
2019-02-22 23:56 ` Alexei Starovoitov
2019-02-23 0:08 ` Linus Torvalds
2019-02-23 2:28 ` Alexei Starovoitov
2019-02-23 2:32 ` Linus Torvalds
2019-02-23 3:02 ` Steven Rostedt
2019-02-23 4:51 ` Masami Hiramatsu
2019-02-26 3:57 ` Christoph Hellwig
2019-02-26 15:24 ` Joel Fernandes
2019-02-28 12:29 ` Masami Hiramatsu
2019-02-28 15:18 ` Joel Fernandes
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190222.151606.344940961752699587.davem@davemloft.net \
--to=davem@davemloft.net \
--cc=akpm@linux-foundation.org \
--cc=alexei.starovoitov@gmail.com \
--cc=bpf@vger.kernel.org \
--cc=changbin.du@gmail.com \
--cc=daniel@iogearbox.net \
--cc=jannh@google.com \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@amacapital.net \
--cc=luto@kernel.org \
--cc=mhiramat@kernel.org \
--cc=mingo@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=rostedt@goodmis.org \
--cc=stable@vger.kernel.org \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).