Messages in this thread | | | From | Max Filippov <> | Date | Thu, 10 Oct 2019 20:35:39 -0700 | Subject | Re: [PATCH] xtensa: fix {get,put}_user() for 64bit values |
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On Thu, Oct 10, 2019 at 7:29 AM Al Viro <viro@zeniv.linux.org.uk> wrote: > Hmm... Looking at __get_user_size(), we have retval = 0; very early > in it. So I wonder if it should simply be > #define __get_user_size(x, ptr, size, retval) \ > do { \ > int __cb; \ > retval = 0; \ > switch (size) { \ > case 1: __get_user_asm(x, ptr, retval, 1, "l8ui", __cb); break;\ > case 2: __get_user_asm(x, ptr, retval, 2, "l16ui", __cb); break;\ > case 4: __get_user_asm(x, ptr, retval, 4, "l32i", __cb); break;\ > case 8: if (unlikely(__copy_from_user(&x, ptr, 8)) { \ > retval = -EFAULT; \ > x = 0; \ > } \ > break; \ > default: (x) = __get_user_bad(); \ > } \ > } while (0) > so that 64bit case is closer to the others in that respect (i.e. zeroing > done on failure and out of line). No?
Ok, I agree. The intermediate __gu_val in __get_user_[no]check doesn't work well with some data types used in the kernel, unfortunately. I'll post a series with what's close to your initial patch on top of rearranged __get_user_[no]check.
-- Thanks. -- Max
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