From: Peter Zijlstra <peterz@infradead.org>
To: Nadav Amit <namit@vmware.com>
Cc: Ingo Molnar <mingo@redhat.com>,
LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Kees Cook <keescook@chromium.org>,
Dave Hansen <dave.hansen@intel.com>,
Masami Hiramatsu <mhiramat@kernel.org>
Subject: Re: [PATCH v4 06/10] x86/alternative: use temporary mm for text poking
Date: Mon, 12 Nov 2018 01:36:38 +0100 [thread overview]
Message-ID: <20181112003638.GA3082@worktop> (raw)
In-Reply-To: <20181111235220.GB3056@worktop>
On Mon, Nov 12, 2018 at 12:52:20AM +0100, Peter Zijlstra wrote:
> On Sun, Nov 11, 2018 at 08:53:07PM +0000, Nadav Amit wrote:
>
> > >> + /*
> > >> + * The lock is not really needed, but this allows to avoid open-coding.
> > >> + */
> > >> + ptep = get_locked_pte(poking_mm, poking_addr, &ptl);
> > >> +
> > >> + /*
> > >> + * If we failed to allocate a PTE, fail. This should *never* happen,
> > >> + * since we preallocate the PTE.
> > >> + */
> > >> + if (WARN_ON_ONCE(!ptep))
> > >> + goto out;
> > >
> > > Since we hard rely on init getting that right; can't we simply get rid
> > > of this?
> > If it is about the way the source code looks - I guess it doesn’t sore my
> > eyes as hard as some other stuff, and I cannot do much about it (other than
> > removing it as you asked).
FWIW per the same argument we should be checking if poking_mm is !NULL.
We also don't do that.
next prev parent reply other threads:[~2018-11-12 0:36 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-10 23:17 [PATCH v4 00/10] x86/alternative: text_poke() fixes Nadav Amit
2018-11-10 23:17 ` [PATCH v4 01/10] Fix "x86/alternatives: Lockdep-enforce text_mutex in text_poke*()" Nadav Amit
2018-11-12 2:54 ` Masami Hiramatsu
2018-11-12 10:59 ` Jiri Kosina
2018-11-10 23:17 ` [PATCH v4 02/10] x86/jump_label: Use text_poke_early() during early init Nadav Amit
2018-11-12 20:12 ` Nadav Amit
2018-11-10 23:17 ` [PATCH v4 03/10] x86/mm: temporary mm struct Nadav Amit
2018-11-10 23:17 ` [PATCH v4 04/10] fork: provide a function for copying init_mm Nadav Amit
2018-11-10 23:17 ` [PATCH v4 05/10] x86/alternative: initializing temporary mm for patching Nadav Amit
2018-11-11 14:43 ` Peter Zijlstra
2018-11-11 20:38 ` Nadav Amit
2018-11-12 0:34 ` Peter Zijlstra
2018-11-10 23:17 ` [PATCH v4 06/10] x86/alternative: use temporary mm for text poking Nadav Amit
2018-11-11 14:59 ` Peter Zijlstra
2018-11-11 20:53 ` Nadav Amit
2018-11-11 23:52 ` Peter Zijlstra
2018-11-12 0:09 ` Nadav Amit
2018-11-12 0:41 ` Peter Zijlstra
2018-11-12 0:36 ` Peter Zijlstra [this message]
2018-11-12 3:46 ` Ingo Molnar
2018-11-12 8:50 ` Peter Zijlstra
2018-11-11 19:11 ` Damian Tometzki
2018-11-11 20:41 ` Nadav Amit
2018-11-10 23:17 ` [PATCH v4 07/10] x86/kgdb: avoid redundant comparison of code Nadav Amit
2018-11-10 23:17 ` [PATCH v4 08/10] x86: avoid W^X being broken during modules loading Nadav Amit
2018-11-10 23:17 ` [PATCH v4 09/10] x86/jump-label: remove support for custom poker Nadav Amit
2018-11-11 15:05 ` Peter Zijlstra
2018-11-11 20:31 ` Nadav Amit
2018-11-10 23:17 ` [PATCH v4 10/10] x86/alternative: remove the return value of text_poke_*() Nadav Amit
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