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From: "Jerome Marchand" <jmarchan@redhat.com>
To: linux-mm@kvack.org, Andrey Ryabinin <ryabinin.a.a@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH V2] mm: vmalloc: don't remove inexistent guard hole in remove_vm_area()
Date: Thu, 12 Nov 2015 17:37:18 +0100	[thread overview]
Message-ID: <1447346238-29153-1-git-send-email-jmarchan@redhat.com> (raw)
In-Reply-To: <1447341424-11466-1-git-send-email-jmarchan@redhat.com>

Commit 71394fe50146 ("mm: vmalloc: add flag preventing guard hole
allocation") missed a spot. Currently remove_vm_area() decreases
vm->size to "remove" the guard hole page, even when it isn't present.
All but one users just free the vm_struct rigth away and never access
vm->size anyway.
Don't touch the size in remove_vm_area() and have __vunmap() use the
proper get_vm_area_size() helper.

Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
---
 mm/vmalloc.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index d045634..8e3c9c5 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1443,7 +1443,6 @@ struct vm_struct *remove_vm_area(const void *addr)
 		vmap_debug_free_range(va->va_start, va->va_end);
 		kasan_free_shadow(vm);
 		free_unmap_vmap_area(va);
-		vm->size -= PAGE_SIZE;
 
 		return vm;
 	}
@@ -1468,8 +1467,8 @@ static void __vunmap(const void *addr, int deallocate_pages)
 		return;
 	}
 
-	debug_check_no_locks_freed(addr, area->size);
-	debug_check_no_obj_freed(addr, area->size);
+	debug_check_no_locks_freed(addr, get_vm_area_size(area));
+	debug_check_no_obj_freed(addr, get_vm_area_size(area));
 
 	if (deallocate_pages) {
 		int i;
-- 
2.4.3

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  parent reply	other threads:[~2015-11-12 16:37 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-12 15:17 [PATCH] mm: vmalloc: don't remove inexistent guard hole in remove_vm_area() Jerome Marchand
2015-11-12 15:55 ` Andrey Ryabinin
2015-11-12 16:28   ` Jerome Marchand
2015-11-12 16:37 ` Jerome Marchand [this message]
2015-11-12 18:48   ` [PATCH V2] " Andrey Ryabinin
2015-11-12 20:55   ` David Rientjes

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