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Date: Fri, 03 May 2002 20:07:47 -0700 (PDT)
Message-Id: <20020503.200747.104775821.davem@redhat.com>
To: bruce.holzrichter@monster.com
Cc: linux-kernel@vger.kernel.org, ak@muc.de
Subject: Re: my slab cache broken on sparc64
From: "David S. Miller" <davem@redhat.com>
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   From: "Holzrichter, Bruce" <bruce.holzrichter@monster.com>
   Date: Fri, 3 May 2002 22:15:56 -0500 

Your patch is buggy:

   +			mm_segment_t old_fs = get_fs();
   +			set_fs(KERNEL_DS);
    			if (__get_user(tmp,pc->name)) { 
    				printk("SLAB: cache with size %d has lost
   its name\n", 
    					pc->objsize); 
    				continue; 
   -			} 	
   +			}
   +			set_fs(old_fs); 	

If the __get_user() fails, you will leave the kernel in the
KERNEL_DS segment.

Do it like this instead.

	int fault;
	mm_segment_t old_fs;

	...

	old_fs = get_fs();
	set_fs(KERNEL_DS);
	fault = __get_user(tmp, pc->name);
	set_fs(old_fs);

	if (fault) {
	...