From: Peter Zijlstra <peterz@infradead.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: David Laight <David.Laight@aculab.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Bill Wendling <morbo@google.com>,
"x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"mark.rutland@arm.com" <mark.rutland@arm.com>,
"dvyukov@google.com" <dvyukov@google.com>,
"seanjc@google.com" <seanjc@google.com>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"mbenes@suse.cz" <mbenes@suse.cz>,
"llvm@lists.linux.dev" <llvm@lists.linux.dev>,
"linux-toolchains@vger.kernel.org"
<linux-toolchains@vger.kernel.org>,
live-patching@vger.kernel.org
Subject: Re: [PATCH 20/22] x86,word-at-a-time: Remove .fixup usage
Date: Fri, 12 Nov 2021 10:33:36 +0100 [thread overview]
Message-ID: <YY408BW0phe9I1/o@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20211112015003.pefl656m3zmir6ov@treble>
On Thu, Nov 11, 2021 at 05:50:03PM -0800, Josh Poimboeuf wrote:
> Hm, I think there is actually a livepatch problem here.
I suspected as much, because I couldn't find any code dealing with it
when I looked in a hurry.. :/
> Some ideas to fix:
> c) Update the reliable stacktrace code to mark the stack unreliable if
> it has a function with ".cold" in the name?
Why not simply match func.cold as func in the transition thing? Then
func won't get patched as long as it (or it's .cold part) is in use.
This seems like the natural thing to do.
If there are enough .cold functions, always reporting stacktrace as
unreliable will make progress hard, even though it might be perfectly
safe.
> e) Disable .cold optimization?
Yeah, lets not do that. That'll have me lobbying to kill KLP again
because it generates crap code.
next prev parent reply other threads:[~2021-11-12 9:34 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-05 17:10 [PATCH 00/22] x86: Remove anonymous out-of-line fixups Peter Zijlstra
2021-11-05 17:10 ` [PATCH 01/22] bitfield.h: Fix "type of reg too small for mask" test Peter Zijlstra
2021-11-05 17:10 ` [PATCH 02/22] x86,mmx_32: Remove .fixup usage Peter Zijlstra
2021-11-05 17:10 ` [PATCH 03/22] x86,copy_user_64: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 04/22] x86,copy_mc_64: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 05/22] x86,entry_64: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 06/22] x86,entry_32: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 07/22] x86,extable: Extend extable functionality Peter Zijlstra
2021-11-05 17:10 ` [PATCH 08/22] x86,msr: Remove .fixup usage Peter Zijlstra
2021-11-05 17:10 ` [PATCH 09/22] x86,futex: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 10/22] x86,uaccess: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 11/22] x86,xen: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 12/22] x86,fpu: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 13/22] x86,segment: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 14/22] x86,vmx: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 15/22] x86,checksum_32: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 16/22] x86,sgx: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 17/22] x86,kvm: " Peter Zijlstra
2021-11-05 17:10 ` [PATCH 18/22] x86,usercopy_32: Simplify __copy_user_intel_nocache() Peter Zijlstra
2021-11-05 17:10 ` [PATCH 19/22] x86,usercopy: Remove .fixup usage Peter Zijlstra
2021-11-05 17:10 ` [PATCH 20/22] x86,word-at-a-time: " Peter Zijlstra
2021-11-05 18:01 ` Josh Poimboeuf
2021-11-05 18:07 ` Peter Zijlstra
2021-11-08 16:47 ` Josh Poimboeuf
2021-11-08 18:29 ` Peter Zijlstra
2021-11-08 18:53 ` Nick Desaulniers
2021-11-09 8:23 ` Peter Zijlstra
2021-11-09 19:22 ` Nick Desaulniers
2021-11-09 20:59 ` Bill Wendling
2021-11-09 21:21 ` Peter Zijlstra
2021-11-09 21:25 ` Nick Desaulniers
2021-11-09 22:11 ` Peter Zijlstra
2021-11-09 22:15 ` Nick Desaulniers
2021-11-09 21:07 ` Peter Zijlstra
2021-11-10 10:18 ` Peter Zijlstra
2021-11-10 10:46 ` David Laight
2021-11-10 11:09 ` Peter Zijlstra
2021-11-10 12:20 ` David Laight
2021-11-12 1:50 ` Josh Poimboeuf
2021-11-12 9:33 ` Peter Zijlstra [this message]
2021-11-13 5:35 ` Josh Poimboeuf
2021-11-15 12:36 ` Miroslav Benes
2021-11-15 13:01 ` Joe Lawrence
2021-11-15 23:40 ` Josh Poimboeuf
2021-11-16 7:25 ` Miroslav Benes
2021-11-15 12:59 ` Miroslav Benes
2021-11-16 21:27 ` Josh Poimboeuf
2021-11-18 7:15 ` Miroslav Benes
2021-11-22 17:46 ` Petr Mladek
2021-11-24 17:42 ` Josh Poimboeuf
2021-11-25 8:18 ` Petr Mladek
2021-11-10 12:14 ` Segher Boessenkool
2021-11-05 17:10 ` [PATCH 21/22] x86: Remove .fixup section Peter Zijlstra
2021-11-05 17:10 ` [PATCH 22/22] objtool: Remove .fixup handling Peter Zijlstra
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