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authorYu-cheng Yu <yu-cheng.yu@intel.com>2017-01-23 14:54:44 -0800
committerIngo Molnar <mingo@kernel.org>2017-01-24 09:04:48 +0100
commitdffba9a31c7769be3231c420d4b364c92ba3f1ac (patch)
treec6cdfe11cb6df51a6e9037ad5b4bcfd2ea8a6574 /include/xen/interface/nmi.h
parent4c833368f0bf748d4147bf301b1f95bc8eccb3c0 (diff)
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. This patch also moves the xcomp_bv initialization to the proper place, which was in copyin_to_xsaves() as of: 4c833368f0bf x86/fpu: Set the xcomp_bv when we fake up a XSAVES area which fixed the bug too, but it's more efficient and cleaner to initialize things once per boot, not for every signal handling operation. Reported-by: Kevin Hao <haokexin@gmail.com> Reported-by: Joakim Tjernlund <Joakim.Tjernlund@infinera.com> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@suse.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: haokexin@gmail.com Link: http://lkml.kernel.org/r/1485212084-4418-1-git-send-email-yu-cheng.yu@intel.com [ Combined it with 4c833368f0bf. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/xen/interface/nmi.h')
0 files changed, 0 insertions, 0 deletions