Re: FAILED: patch "[PATCH] x86/module: Fix the paravirt vs alternative order" failed to apply to 5.15-stable tree

[Borislav Petkov <bp@suse.de>]

On Mon, Mar 14, 2022 at 09:04:06AM +0100, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 5.15-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.
> 
> thanks,
> 
> greg k-h
> 
> ------------------ original commit in Linus's tree ------------------
> 
> From 5adf349439d29f92467e864f728dfc23180f3ef9 Mon Sep 17 00:00:00 2001

I guess something like this:

From 8fb38dd5ae4b4f94e5944651965d4b2e8168d46a Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Thu, 3 Mar 2022 12:23:23 +0100
Subject: [PATCH] x86/module: Fix the paravirt vs alternative order

Commit 5adf349439d29f92467e864f728dfc23180f3ef9 upstream.

Ever since commit

  4e6292114c74 ("x86/paravirt: Add new features for paravirt patching")

there is an ordering dependency between patching paravirt ops and
patching alternatives, the module loader still violates this.

Fixes: 4e6292114c74 ("x86/paravirt: Add new features for paravirt patching")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220303112825.068773913@infradead.org
---
 arch/x86/kernel/module.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index 867a341a0c7e..32e546e41629 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -270,6 +270,14 @@ int module_finalize(const Elf_Ehdr *hdr,
 			orc_ip = s;
 	}
 
+	/*
+	 * See alternative_instructions() for the ordering rules between the
+	 * various patching types.
+	 */
+	if (para) {
+		void *pseg = (void *)para->sh_addr;
+		apply_paravirt(pseg, pseg + para->sh_size);
+	}
 	if (alt) {
 		/* patch .altinstructions */
 		void *aseg = (void *)alt->sh_addr;
@@ -283,11 +291,6 @@ int module_finalize(const Elf_Ehdr *hdr,
 					    tseg, tseg + text->sh_size);
 	}
 
-	if (para) {
-		void *pseg = (void *)para->sh_addr;
-		apply_paravirt(pseg, pseg + para->sh_size);
-	}
-
 	/* make jump label nops */
 	jump_label_apply_nops(me);
 
-- 
2.29.2

-- 
Regards/Gruss,
    Boris.

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