BPF Archive on lore.kernel.org
 help / color / Atom feed
From: Peter Zijlstra <peterz@infradead.org>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Nikolay Borisov <nborisov@suse.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Alexei Starovoitov <ast@kernel.org>, bpf <bpf@vger.kernel.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>
Subject: Re: kprobes broken since 0d00449c7a28 ("x86: Replace ist_enter() with nmi_enter()")
Date: Fri, 29 Jan 2021 18:59:43 +0100
Message-ID: <20210129175943.GH8912@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <CAADnVQLMqHpSsZ1OdZRFmKqNWKiRq3dxRxw+y=kvMdmkN7htUw@mail.gmail.com>

On Fri, Jan 29, 2021 at 09:45:48AM -0800, Alexei Starovoitov wrote:
> Same things apply to bpf side. We can statically prove safety for
> ftrace and kprobe attaching whereas to deal with NMI situation we
> have to use run-time checks for recursion prevention, etc.

I have no idea what you're saying. You can attach to functions that are
called with random locks held, you can create kprobes in some very
sensitive places.

What can you staticlly prove about that?


  reply index

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <25cd2608-03c2-94b8-7760-9de9935fde64@suse.com>
     [not found] ` <20210128001353.66e7171b395473ef992d6991@kernel.org>
     [not found]   ` <20210128002452.a79714c236b69ab9acfa986c@kernel.org>
     [not found]     ` <a35a6f15-9ab1-917c-d443-23d3e78f2d73@suse.com>
     [not found]       ` <20210128103415.d90be51ec607bb6123b2843c@kernel.org>
2021-01-28  3:38         ` Masami Hiramatsu
2021-01-28  7:11           ` Nikolay Borisov
2021-01-28 16:12           ` Nikolay Borisov
2021-01-28 16:45             ` Nikolay Borisov
2021-01-28 16:50               ` Josh Poimboeuf
2021-01-28 21:52                 ` [PATCH] x86: Disable CET instrumentation in the kernel Josh Poimboeuf
2021-01-29  6:23                   ` Nikolay Borisov
2021-01-29 10:21                   ` Borislav Petkov
     [not found]                     ` <20210129151034.iba4eaa2fuxsipqa@treble>
2021-01-29 16:30                       ` Borislav Petkov
2021-01-29 16:49                         ` Josh Poimboeuf
2021-01-29 16:54                           ` Nikolay Borisov
2021-01-29 17:03                             ` Josh Poimboeuf
2021-01-29 17:07                               ` Borislav Petkov
2021-01-29 17:58                                 ` Seth Forshee
2021-01-28 18:24               ` kprobes broken since 0d00449c7a28 ("x86: Replace ist_enter() with nmi_enter()") Peter Zijlstra
2021-01-29  1:34                 ` Alexei Starovoitov
2021-01-29  6:36                   ` Nikolay Borisov
     [not found]                   ` <YBPNyRyrkzw2echi@hirez.programming.kicks-ass.net>
     [not found]                     ` <20210129224011.81bcdb3eba1227c414e69e1f@kernel.org>
     [not found]                       ` <20210129105952.74dc8464@gandalf.local.home>
2021-01-29 16:24                         ` Peter Zijlstra
2021-01-29 17:45                           ` Alexei Starovoitov
2021-01-29 17:59                             ` Peter Zijlstra [this message]
2021-01-29 19:01                               ` Steven Rostedt
2021-01-29 21:05                                 ` Alexei Starovoitov
2021-01-30  1:41                                   ` Masami Hiramatsu
2021-01-29 21:24                                 ` Steven Rostedt
2021-01-30  8:28                                   ` Peter Zijlstra
2021-01-30 12:44                                     ` Steven Rostedt
2021-02-02 10:45                                       ` Peter Zijlstra
2021-02-02 14:52                                         ` Steven Rostedt
2021-02-02 16:45                                           ` Peter Zijlstra
2021-02-02 16:56                                             ` Steven Rostedt
2021-02-02 18:30                                               ` Peter Zijlstra
2021-02-02 21:05                                                 ` Steven Rostedt
2021-02-03 13:33                                                   ` Masami Hiramatsu
2021-02-03 13:52                                                     ` Steven Rostedt
2021-01-30  2:02                               ` Masami Hiramatsu
2021-01-30  3:08                                 ` Alexei Starovoitov
2021-01-30 12:10                                   ` Masami Hiramatsu

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=20210129175943.GH8912@worktop.programming.kicks-ass.net \
    --to=peterz@infradead.org \
    --cc=alexei.starovoitov@gmail.com \
    --cc=ast@kernel.org \
    --cc=bpf@vger.kernel.org \
    --cc=jpoimboe@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mhiramat@kernel.org \
    --cc=nborisov@suse.com \
    --cc=rostedt@goodmis.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

BPF Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/bpf/0 bpf/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 bpf bpf/ https://lore.kernel.org/bpf \
		bpf@vger.kernel.org
	public-inbox-index bpf

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.bpf


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git