linux-kernel - [tip: x86/urgent] x86/module: Fix the paravirt vs alternative order

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Date:   Tue, 08 Mar 2022 13:58:55 -0000
From:   "tip-bot2 for Peter Zijlstra" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Borislav Petkov <bp@...e.de>, Miroslav Benes <mbenes@...e.cz>,
        <stable@...r.kernel.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: x86/urgent] x86/module: Fix the paravirt vs alternative order

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     5adf349439d29f92467e864f728dfc23180f3ef9
Gitweb:        https://git.kernel.org/tip/5adf349439d29f92467e864f728dfc23180f3ef9
Author:        Peter Zijlstra <peterz@...radead.org>
AuthorDate:    Thu, 03 Mar 2022 12:23:23 +01:00
Committer:     Borislav Petkov <bp@...e.de>
CommitterDate: Tue, 08 Mar 2022 14:15:25 +01:00

x86/module: Fix the paravirt vs alternative order

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@...radead.org>
Signed-off-by: Borislav Petkov <bp@...e.de>
Reviewed-by: Miroslav Benes <mbenes@...e.cz>
Cc: <stable@...r.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 95fa745..96d7c27 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -273,6 +273,14 @@ int module_finalize(const Elf_Ehdr *hdr,
 			retpolines = 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 (retpolines) {
 		void *rseg = (void *)retpolines->sh_addr;
 		apply_retpolines(rseg, rseg + retpolines->sh_size);
@@ -290,11 +298,6 @@ 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);