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From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>,
	Borislav Petkov <bp@alien8.de>,
	David Kaplan <david.kaplan@amd.com>,
	x86@kernel.org, luto@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] Revert "x86/retpoline: Remove .text..__x86.return_thunk section"
Date: Thu, 12 Oct 2023 00:42:42 +0200	[thread overview]
Message-ID: <ZSck4mcr6sKS/ob7@gmail.com> (raw)
In-Reply-To: <20231011223513.GH6307@noisy.programming.kicks-ass.net>


* Peter Zijlstra <peterz@infradead.org> wrote:

> I don't care too deeply, I can't make up my mind either way. But perhaps 
> keeping the section is easier on all the backports, it's easy to forget a 
> tiny objtool patch like this.

If the objtool fix has a Fixes tag that points to one of the major 
mitigation commits, then it won't be forgotten.

Arguably the new objtool is more robust against what could happen, so that 
patch is not going away - and with that patch mainline doesn't have to keep 
the (now ...) pointless section.

Maybe change the commit order around: first add the objtool fix, then 
remove the section, pointing back to the objtool SHA1 in the very next 
commit, explaining that the objtool fix enables this change. That makes it 
all backporting-proof as well.

Thanks,

	Ingo

  reply	other threads:[~2023-10-11 22:42 UTC|newest]

Thread overview: 93+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-10 17:10 [PATCH 0/3] Ensure default return thunk isn't used at runtime David Kaplan
2023-10-10 17:10 ` [PATCH 1/3] Revert "x86/retpoline: Remove .text..__x86.return_thunk section" David Kaplan
2023-10-10 17:48   ` Peter Zijlstra
2023-10-10 19:57     ` Josh Poimboeuf
2023-10-10 20:04       ` Borislav Petkov
2023-10-10 20:19         ` Josh Poimboeuf
2023-10-10 20:40           ` Kaplan, David
2023-10-10 21:22           ` Josh Poimboeuf
2023-10-11  7:41             ` Peter Zijlstra
2023-10-11  9:34               ` Borislav Petkov
2023-10-11 16:28               ` Josh Poimboeuf
2023-10-11 22:35                 ` Peter Zijlstra
2023-10-11 22:42                   ` Ingo Molnar [this message]
2023-10-12  2:27                   ` Josh Poimboeuf
2023-10-12  2:47                     ` [PATCH v2] objtool: Fix return thunk patching in retpolines Josh Poimboeuf
2023-10-12  6:25                       ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-10-12  8:16                       ` [PATCH v2] " Peter Zijlstra
2023-10-12 17:50                       ` [tip: x86/bugs] " tip-bot2 for Josh Poimboeuf
2023-10-20 11:37                       ` tip-bot2 for Josh Poimboeuf
2023-10-12  8:16                     ` [PATCH 1/3] Revert "x86/retpoline: Remove .text..__x86.return_thunk section" Peter Zijlstra
2023-10-10 17:10 ` [PATCH 2/3] x86/vdso: Run objtool on vdso32-setup David Kaplan
2023-10-12 17:50   ` [tip: x86/bugs] x86/vdso: Run objtool on vdso32-setup.o tip-bot2 for David Kaplan
2023-10-20 11:37   ` tip-bot2 for David Kaplan
2023-10-10 17:10 ` [PATCH 3/3] x86/retpoline: Ensure default return thunk isn't used at runtime David Kaplan
2023-10-10 19:36   ` Josh Poimboeuf
2023-10-10 20:14     ` Kaplan, David
2023-10-10 20:41       ` Josh Poimboeuf
2023-10-12 14:10         ` [PATCH -v2] " Borislav Petkov
2023-10-12 17:11           ` Josh Poimboeuf
2023-10-12 17:50           ` [tip: x86/bugs] " tip-bot2 for David Kaplan
2023-10-16 21:10             ` Nathan Chancellor
2023-10-16 21:29               ` Borislav Petkov
2023-10-16 21:48                 ` Nathan Chancellor
2023-10-17  4:31                   ` Kaplan, David
2023-10-17  5:28                     ` Josh Poimboeuf
2023-10-17 13:54                       ` Kaplan, David
2023-10-17 15:24                       ` Nick Desaulniers
2023-10-17 15:26                         ` Marco Elver
2023-10-17 15:32                       ` Nathan Chancellor
2023-10-17 16:59                         ` [PATCH] x86/srso: Fix panic in return thunk during boot Josh Poimboeuf
2023-10-17 17:52                           ` [tip: x86/bugs] x86/retpoline: Make sure there are no unconverted return thunks due to KCSAN tip-bot2 for Josh Poimboeuf
2023-10-20 11:37                           ` tip-bot2 for Josh Poimboeuf
2023-10-18 13:23             ` [tip: x86/bugs] x86/retpoline: Ensure default return thunk isn't used at runtime Borislav Petkov
2023-10-18 13:38               ` Ingo Molnar
2023-10-18 15:12                 ` Borislav Petkov
2023-10-18 15:54                   ` Josh Poimboeuf
2023-10-18 17:55                     ` Borislav Petkov
2023-10-18 18:14                       ` Josh Poimboeuf
2023-10-18 18:22                         ` Borislav Petkov
2023-10-18 18:39                           ` Josh Poimboeuf
2023-10-18 18:44                             ` Borislav Petkov
2023-10-18 19:14                               ` Josh Poimboeuf
2023-10-18 20:04                                 ` Borislav Petkov
2023-10-18 20:37                       ` Borislav Petkov
2023-10-19  6:35                         ` Josh Poimboeuf
2023-10-19  6:59                           ` Josh Poimboeuf
2023-10-19 14:15                             ` Borislav Petkov
2023-10-19 14:21                               ` Kaplan, David
2023-10-19 14:39                                 ` Borislav Petkov
2023-10-19 15:20                                   ` Josh Poimboeuf
2023-10-24 20:19                                     ` Borislav Petkov
2024-01-03 18:46                                       ` Borislav Petkov
2024-01-04 13:12                                         ` Borislav Petkov
2024-01-04 13:24                                           ` [PATCH -v2] " Borislav Petkov
2024-01-04 13:26                                             ` Borislav Petkov
2024-02-07 17:50                                               ` Josh Poimboeuf
2024-02-07 18:53                                                 ` Borislav Petkov
2024-02-07 19:49                                                   ` Josh Poimboeuf
2024-02-12 10:43                                                     ` Borislav Petkov
2024-04-03 17:10                                                       ` Klara Modin
2024-04-03 17:30                                                         ` Borislav Petkov
2024-04-03 20:26                                                           ` Klara Modin
2024-04-03 20:41                                                             ` Borislav Petkov
2024-04-03 22:25                                                               ` Klara Modin
2024-04-04 14:44                                                                 ` Borislav Petkov
2024-04-16  9:27                                                         ` Borislav Petkov
2024-04-17  3:59                                                           ` Klara Modin
2024-04-17 16:20                                                         ` [tip: x86/urgent] x86/retpolines: Enable the default thunk warning only on relevant configs tip-bot2 for Borislav Petkov (AMD)
2023-10-19  7:43                         ` [tip: x86/bugs] x86/retpoline: Ensure default return thunk isn't used at runtime Peter Zijlstra
2023-10-19  9:40                       ` [tip: x86/bugs] Revert "x86/retpoline: Remove .text..__x86.return_thunk section" tip-bot2 for Borislav Petkov (AMD)
2023-10-19  9:40                       ` [tip: x86/bugs] Revert "x86/retpoline: Ensure default return thunk isn't used at runtime" tip-bot2 for Borislav Petkov (AMD)
2024-10-04 19:37                         ` Peter Zijlstra
2024-02-12 14:13   ` [tip: x86/bugs] x86/retpoline: Ensure default return thunk isn't used at runtime tip-bot2 for Josh Poimboeuf
2024-02-15  3:20     ` Nathan Chancellor
2024-02-15  8:30       ` Nikolay Borisov
2024-02-15 15:53       ` Borislav Petkov
2024-02-16  5:42         ` Josh Poimboeuf
2024-02-16 21:27           ` Borislav Petkov
2024-02-20  5:57             ` [PATCH] x86/vdso: Fix rethunk patching for vdso-image-{32,64}.o Josh Poimboeuf
2024-02-20 12:31       ` [tip: x86/core] " tip-bot2 for Josh Poimboeuf
2023-10-10 17:52 ` [PATCH 0/3] Ensure default return thunk isn't used at runtime Peter Zijlstra
2023-10-20 11:28 ` Subject: [PATCH] x86/retpoline: Document some thunk handling aspects (was: Re: [PATCH 0/3] Ensure default return thunk isn't used at runtime) Borislav Petkov
2023-10-20 11:37 ` [tip: x86/bugs] x86/retpoline: Document some thunk handling aspects tip-bot2 for Borislav Petkov (AMD)

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