On Thu, Jul 17, 2014 at 7:07 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > The get_user/put_user functions really need to be annotated might_fault(), > because that's what they do. > > The whole point of get_user() is to access an unchecked user space > pointer, which can do a number of things based on what the pointer > points to: > > - access a user space variable that resides in memory > - access a kernel pointer and fail because of the access_ok() > check > - access a user space pointer that is not mapped and return > through the __ex_table fixup. > - access a user space pointer that has a valid VMA but not PTE, > causing a page fault to be resolved. > > It's the last case that breaks here. So, do you mean that we can't use get_user/put_user in futex support? BTW, some architectures like sh,parisc, m68k use get_user in futex function as well. Any recommendation way to support futex if we can't use get_user. Note, nios2 doesn't have atomic instruction. Thanks. Regards Ley Foon -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
