[PATCH 2/2] vmalloc: reject vmap with VM_FLUSH_RESET_PERMS

From: Christoph Hellwig <hch@lst.de>
To: Andy Gross <agross@kernel.org>,
	Bjorn Andersson <andersson@kernel.org>,
	Konrad Dybcio <konrad.dybcio@linaro.org>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Uladzislau Rezki <urezki@gmail.com>
Cc: linux-arm-msm@vger.kernel.org, linux-remoteproc@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	iommu@lists.linux.dev
Subject: [PATCH 2/2] vmalloc: reject vmap with VM_FLUSH_RESET_PERMS
Date: Fri, 23 Dec 2022 10:27:03 +0100	[thread overview]
Message-ID: <20221223092703.61927-3-hch@lst.de> (raw)
In-Reply-To: <20221223092703.61927-1-hch@lst.de>

VM_FLUSH_RESET_PERMS is just for use with vmalloc as it is tied to freeing
the underlying pages.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 mm/vmalloc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 9e30f0b3920325..88a644cde9fb12 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2849,6 +2849,9 @@ void *vmap(struct page **pages, unsigned int count,
 
 	might_sleep();
 
+	if (WARN_ON_ONCE(flags & VM_FLUSH_RESET_PERMS))
+		return NULL;
+
 	/*
 	 * Your top guard is someone else's bottom guard. Not having a top
 	 * guard compromises someone else's mappings too.
-- 
2.35.1

