linux-kernel - [PATCH v8 5/5] arm64: kprobes: call set_memory

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Message-ID: <20250917190323.3828347-6-yang@os.amperecomputing.com>
Date: Wed, 17 Sep 2025 12:02:11 -0700
From: Yang Shi <yang@...amperecomputing.com>
To: catalin.marinas@....com,
	will@...nel.org,
	ryan.roberts@....com,
	akpm@...ux-foundation.org,
	david@...hat.com,
	lorenzo.stoakes@...cle.com,
	ardb@...nel.org,
	dev.jain@....com,
	scott@...amperecomputing.com,
	cl@...two.org
Cc: yang@...amperecomputing.com,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org
Subject: [PATCH v8 5/5] arm64: kprobes: call set_memory_rox() for kprobe page

The kprobe page is allocated by execmem allocator with ROX permission.
It needs to call set_memory_rox() to set proper permission for the
direct map too. It was missed.

And the set_memory_rox() guarantees the direct map will be split if it
needs so that set_direct_map calls in vfree() won't fail.

Fixes: 10d5e97c1bf8 ("arm64: use PAGE_KERNEL_ROX directly in alloc_insn_page")
Signed-off-by: Yang Shi <yang@...amperecomputing.com>
---
 arch/arm64/kernel/probes/kprobes.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
index 0c5d408afd95..c4f8c4750f1e 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -10,6 +10,7 @@
 
 #define pr_fmt(fmt) "kprobes: " fmt
 
+#include <linux/execmem.h>
 #include <linux/extable.h>
 #include <linux/kasan.h>
 #include <linux/kernel.h>
@@ -41,6 +42,17 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 static void __kprobes
 post_kprobe_handler(struct kprobe *, struct kprobe_ctlblk *, struct pt_regs *);
 
+void *alloc_insn_page(void)
+{
+	void *page;
+
+	page = execmem_alloc(EXECMEM_KPROBES, PAGE_SIZE);
+	if (!page)
+		return NULL;
+	set_memory_rox((unsigned long)page, 1);
+	return page;
+}
+
 static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
 {
 	kprobe_opcode_t *addr = p->ainsn.xol_insn;
-- 
2.47.0