linux-kernel - [PATCH 1/2] arm64/pageattr: Propagate return value from __change_memory

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Message-Id: <20251112062716.64801-2-dev.jain@arm.com>
Date: Wed, 12 Nov 2025 11:57:15 +0530
From: Dev Jain <dev.jain@....com>
To: catalin.marinas@....com,
	will@...nel.org
Cc: ryan.roberts@....com,
	rppt@...nel.org,
	shijie@...amperecomputing.com,
	yang@...amperecomputing.com,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Dev Jain <dev.jain@....com>
Subject: [PATCH 1/2] arm64/pageattr: Propagate return value from __change_memory_common

The rodata=on security measure requires that any code path which does
vmalloc -> set_memory_ro/set_memory_rox must protect the linear map alias
too. Therefore, if such a call fails, we must abort set_memory_* and caller
must take appropriate action; currently we are suppressing the error, and
there is a real chance of such an error arising post commit a166563e7ec3
("arm64: mm: support large block mapping when rodata=full"). Therefore,
propagate any error to the caller.

Fixes: a166563e7ec3 ("arm64: mm: support large block mapping when rodata=full")
Signed-off-by: Dev Jain <dev.jain@....com>
---
v1 of this patch: https://lore.kernel.org/all/20251103061306.82034-1-dev.jain@arm.com/
I have dropped stable since no real chance of failure was there.

 arch/arm64/mm/pageattr.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index 5135f2d66958..b4ea86cd3a71 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -148,6 +148,7 @@ static int change_memory_common(unsigned long addr, int numpages,
 	unsigned long size = PAGE_SIZE * numpages;
 	unsigned long end = start + size;
 	struct vm_struct *area;
+	int ret;
 	int i;
 
 	if (!PAGE_ALIGNED(addr)) {
@@ -185,8 +186,10 @@ static int change_memory_common(unsigned long addr, int numpages,
 	if (rodata_full && (pgprot_val(set_mask) == PTE_RDONLY ||
 			    pgprot_val(clear_mask) == PTE_RDONLY)) {
 		for (i = 0; i < area->nr_pages; i++) {
-			__change_memory_common((u64)page_address(area->pages[i]),
+			ret = __change_memory_common((u64)page_address(area->pages[i]),
 					       PAGE_SIZE, set_mask, clear_mask);
+			if (ret)
+				return ret;
 		}
 	}
 
-- 
2.30.2