Messages in this thread | | | Date | Sat, 15 Jan 2005 22:39:06 +0100 | From | Sam Ravnborg <> | Subject | slab.c use of __get_user and sparse |
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Hi Andi, lkml.
In slab.c around line 1450 the following code is present:
list_for_each(p, &cache_chain) { kmem_cache_t *pc = list_entry(p, kmem_cache_t, next); char tmp; /* This happens when the module gets unloaded and doesn't destroy its slab cache and noone else reuses the vmalloc area of the module. Print a warning. */ if (__get_user(tmp,(char __user *) pc->name)) { printk("SLAB: cache with size %d has lost its name\n", pc->objsize); continue;
sparse emit a warning for the line with __get_user because the pointer is not marker __user. So the above cast inserted by me made sparse shut up.
Based on the comment it is understood that suddenly this pointer points to userspace, because the module got unloaded. I wonder why we can rely on the same address now the module got unloaded - we may risk this virtual address is taken over by someone else?
Andi - sent to you since you made this change loong time ago.
[mm/ is sparse clean with defconfig when this is fixed].
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