From 8e36709d8cea48a4d341294ce2b46678a2e77159 Mon Sep 17 00:00:00 2001 From: KAMEZAWA Hiroyuki Date: Fri, 10 Feb 2006 01:51:12 -0800 Subject: [PATCH] [PATCH] shmdt cannot detach not-alined shm segment cleanly. sys_shmdt() can manage shm segments which are covered by multiple vmas. (This can happen when a user uses mprotect() after shmat().) This works well if shm is aligned to PAGE_SIZE, but if not, the last segment cannot be detached. It is because a comparison in sys_shmdt() (vma->vm_end - addr) < size addr == return address of shmat() size == shmsize, argments to shmget() size should be aligned to PAGE_SIZE before being compared with vma->vm_end, which is aligned. Signed-off-by: KAMEZAWA Hiroyuki Cc: Manfred Spraul Acked-by: Hugh Dickins Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- ipc/shm.c | 1 + 1 file changed, 1 insertion(+) diff --git a/ipc/shm.c b/ipc/shm.c index 4c28d2d8e305..9162123a7b23 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -870,6 +870,7 @@ asmlinkage long sys_shmdt(char __user *shmaddr) * could possibly have landed at. Also cast things to loff_t to * prevent overflows and make comparisions vs. equal-width types. */ + size = PAGE_ALIGN(size); while (vma && (loff_t)(vma->vm_end - addr) <= size) { next = vma->vm_next; -- 2.20.1