On Tue, Jan 24, 2017 at 12:46:17AM -0800, tip-bot for Yu-cheng Yu wrote: > Commit-ID: dffba9a31c7769be3231c420d4b364c92ba3f1ac > Gitweb: http://git.kernel.org/tip/dffba9a31c7769be3231c420d4b364c92ba3f1ac > Author: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx> > AuthorDate: Mon, 23 Jan 2017 14:54:44 -0800 > Committer: Ingo Molnar <mingo@xxxxxxxxxx> > CommitDate: Tue, 24 Jan 2017 09:04:48 +0100 > > x86/fpu/xstate: Fix xcomp_bv in XSAVES header > > The compacted-format XSAVES area is determined at boot time and > never changed after. The field xsave.header.xcomp_bv indicates > which components are in the fixed XSAVES format. > > In fpstate_init() we did not set xcomp_bv to reflect the XSAVES > format since at the time there is no valid data. > > However, after we do copy_init_fpstate_to_fpregs() in fpu__clear(), > as in commit: > > b22cbe404a9c x86/fpu: Fix invalid FPU ptrace state after execve() > > and when __fpu_restore_sig() does fpu__restore() for a COMPAT-mode > app, a #GP occurs. This can be easily triggered by doing valgrind on > a COMPAT-mode "Hello World," as reported by Joakim Tjernlund and > others: > > https://bugzilla.kernel.org/show_bug.cgi?id=190061 > > Fix it by setting xcomp_bv correctly. > Please consider pulling this into the stable tree because my previous patch in commit: b22cbe404a9c x86/fpu: Fix invalid FPU ptrace state after execve() exposes the same issue in the stable tree. Thanks, Yu-cheng