From: Christoph Hellwig <hch@lst.de>
Date: Sat, 21 Jan 2023 07:10:42 +0000 (+0100)
Subject: mm: reject vmap with VM_FLUSH_RESET_PERMS
X-Git-Tag: microblaze-v6.6~1071^2~189
X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=37f3605e5e7af7de12aeb670c5b94e5a3c8dbf74;p=linux-2.6-microblaze.git

mm: reject vmap with VM_FLUSH_RESET_PERMS

Patch series "cleanup vfree and vunmap".

This little series untangles the vfree and vunmap code path a bit.


This patch (of 10):

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

Link: https://lkml.kernel.org/r/20230121071051.1143058-1-hch@lst.de
Link: https://lkml.kernel.org/r/20230121071051.1143058-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 428e0bee5c9c..3f3cb4875966 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2868,6 +2868,9 @@ 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.