Messages in this thread | | | Date | Tue, 28 Apr 2015 15:09:17 -0700 | From | Dave Hansen <> | Subject | Re: [PATCH Bugfix v2 2/4] x86/xsaves: Define and use user_xstate_size for xstate size in signal context |
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On 04/21/2015 09:51 PM, Fenghua Yu wrote: > + /* > + * Clear xcomp_bv[63] in user's xsave area header to indicate > + * buf_fx is in standard format. > + */ > + xcomp_bv = xsave->xsave_hdr.xcomp_bv; > + user_xsave = buf_fx; > + xcomp_bv &= ~((u64)1 << 63);
I ran in to another bug. xrestor_user() is hitting a #GP with these values:
[ 6.258743] xrestore_user() tmp: ffff88003f813000 [ 6.261122] XCR0: 000000000000001f [ 6.261868] xstate_bv: 0000000000000003 [ 6.262613] xcomp_bv: 000000000000001f
I think it is because bit 63 is clear in xcomp_bv, but there are other bits set in there.
I think the above needs to just do:
/* * We are uncompacting the state for the user buffer. We need * to clear out the xcomp_bv field entirely. The uncompacted * form of xsave/xrstor treats this field as reserved. */ if (__put_user(0, &user_xsave->xsave_hdr.xcomp_bv)) return -1;
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