linux-kernel - [PATCH] powerpc/kprobes: Handle error returned by set_memory

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Message-ID: <b4907cf4339bd086abc40430d91311436cb0c18e.1708078401.git.christophe.leroy@csgroup.eu>
Date: Fri, 16 Feb 2024 11:13:28 +0100
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Michael Ellerman <mpe@...erman.id.au>,
	Nicholas Piggin <npiggin@...il.com>
Cc: Christophe Leroy <christophe.leroy@...roup.eu>,
	linux-kernel@...r.kernel.org,
	linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH] powerpc/kprobes: Handle error returned by set_memory_rox()

set_memory_rox() can fail.

In case it fails, free allocated memory and return NULL.

Link: https://github.com/KSPP/linux/issues/7
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 arch/powerpc/kernel/kprobes.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index b20ee72e873a..bbca90a5e2ec 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -134,10 +134,16 @@ void *alloc_insn_page(void)
 	if (!page)
 		return NULL;
 
-	if (strict_module_rwx_enabled())
-		set_memory_rox((unsigned long)page, 1);
+	if (strict_module_rwx_enabled()) {
+		int err = set_memory_rox((unsigned long)page, 1);
 
+		if (err)
+			goto error;
+	}
 	return page;
+error:
+	module_memfree(page);
+	return NULL;
 }
 
 int arch_prepare_kprobe(struct kprobe *p)
-- 
2.43.0