From: Kees Cook <kees@kernel.org>
To: Ard Biesheuvel <ardb@kernel.org>, Steven Rostedt <rostedt@goodmis.org>
Cc: Mike Rapoport <rppt@kernel.org>,
linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Vlastimil Babka <vbabka@suse.cz>,
Lorenzo Stoakes <lstoakes@gmail.com>,
linux-mm@kvack.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Peter Zijlstra <peterz@infradead.org>,
Tony Luck <tony.luck@intel.com>,
"Guilherme G. Piccoli" <gpiccoli@igalia.com>,
linux-hardening@vger.kernel.org,
Guenter Roeck <linux@roeck-us.net>,
Ross Zwisler <zwisler@google.com>,
wklin@google.com,
Vineeth Remanan Pillai <vineeth@bitbyteword.org>,
Joel Fernandes <joel@joelfernandes.org>,
Suleiman Souhlal <suleiman@google.com>,
Linus Torvalds <torvalds@linuxfoundation.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>
Subject: Re: [PATCH v3 2/2] pstore/ramoops: Add ramoops.mem_name= command line option
Date: Thu, 13 Jun 2024 07:42:01 -0700 [thread overview]
Message-ID: <CB84A272-24F0-4526-8474-0D0CD5C5E27C@kernel.org> (raw)
In-Reply-To: <CAMj1kXFGnk4vYpTk4PwUg8iYHcbXdrPaYP+OBxHrD5+=jvow+g@mail.gmail.com>
On June 13, 2024 7:06:47 AM PDT, Ard Biesheuvel <ardb@kernel.org> wrote:
>On Thu, 13 Jun 2024 at 15:26, Steven Rostedt <rostedt@goodmis.org> wrote:
>>
>> On Thu, 13 Jun 2024 08:11:48 +0200
>> Ard Biesheuvel <ardb@kernel.org> wrote:
>> > >
>> > > I've added one more comment to v5, with that fixed I can take this.
>> > >
>> >
>> > So how is this supposed to work wrt to the rigid 'no user visible
>> > regressions' rule, given that this whole thing is a best effort thing
>>
>> This has nothing to do with user space. The kernel command line has
>> broken in the past. If you update the kernel, you can update the
>> command line. There's no "no user visible regressions" rule. It's
>> "Don't break user space". This has nothing to do with user space.
>>
>> > to begin with. This needs at least a huge disclaimer that this rule
>> > does not apply, and if this works today, there is no guarantee that it
>> > will keep working on newer kernels. Otherwise, you will be making the
>> > job of the people who work on the boot code significantly more
>> > difficult. And even then, I wonder whether Linus and #regzcop are
>> > going to honour such a disclaimer.
>>
>> Again, this has nothing to do with user space. The rule Linus talks
>> about is breaking user space. This is about kernel debugging. Something
>> *completely different*!
>>
>> >
>> > So this belongs downstream, unless some guarantees can be provided
>> > that this functionality is exempt from the usual regression policies.
>>
>> I disagree. kexec/kdump also has the same issues.
>>
>
>Fair enough. As long as it is documented that there is no guarantee
>that this will keep working over a kernel upgrade, then I have no
>objections.
Yeah, I should better document this for pstore as a whole, but I've already made the call that cross-kernel-versison operation is best effort.
-Kees
--
Kees Cook
prev parent reply other threads:[~2024-06-13 14:42 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-11 14:49 [PATCH v3 0/2] mm/memblock: Add "reserve_mem" to reserved named memory at boot up Steven Rostedt
2024-06-11 14:49 ` [PATCH v3 1/2] " Steven Rostedt
2024-06-11 14:49 ` [PATCH v3 2/2] pstore/ramoops: Add ramoops.mem_name= command line option Steven Rostedt
2024-06-12 18:45 ` Kees Cook
2024-06-12 18:52 ` Steven Rostedt
2024-06-13 6:02 ` Mike Rapoport
2024-06-13 6:11 ` Ard Biesheuvel
2024-06-13 13:26 ` Steven Rostedt
2024-06-13 14:06 ` Ard Biesheuvel
2024-06-13 14:31 ` Steven Rostedt
2024-06-13 14:42 ` Kees Cook [this message]
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