[PATCH 5.15 24/25] x86/module: Fix the paravirt vs alternative order

Greg Kroah-Hartman
2022-03-17T12:56:11Z

From: Peter Zijlstra <peterz@infradead.org>

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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/module.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

--- 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);