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-rw-r--r--0001-x86-fpu-Fix-invalid-FPU-ptrace-state-after-execve.patch65
1 files changed, 65 insertions, 0 deletions
diff --git a/0001-x86-fpu-Fix-invalid-FPU-ptrace-state-after-execve.patch b/0001-x86-fpu-Fix-invalid-FPU-ptrace-state-after-execve.patch
new file mode 100644
index 00000000000..8cef8463520
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+++ b/0001-x86-fpu-Fix-invalid-FPU-ptrace-state-after-execve.patch
@@ -0,0 +1,65 @@
+From 885bad1e5f32bbf30787ead9578f8174047e6904 Mon Sep 17 00:00:00 2001
+From: Yu-cheng Yu <yu-cheng.yu@intel.com>
+Date: Thu, 17 Nov 2016 09:11:35 -0800
+Subject: [PATCH] x86/fpu: Fix invalid FPU ptrace state after execve()
+
+commit b22cbe404a9cc3c7949e380fa1861e31934c8978 upstream.
+
+Robert O'Callahan reported that after an execve PTRACE_GETREGSET
+NT_X86_XSTATE continues to return the pre-exec register values
+until the exec'ed task modifies FPU state.
+
+The test code is at:
+
+ https://bugzilla.redhat.com/attachment.cgi?id=1164286.
+
+What is happening is fpu__clear() does not properly clear fpstate.
+Fix it by doing just that.
+
+Reported-by: Robert O'Callahan <robert@ocallahan.org>
+Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
+Cc: Andy Lutomirski <luto@kernel.org>
+Cc: Borislav Petkov <bp@suse.de>
+Cc: David 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>
+Link: http://lkml.kernel.org/r/1479402695-6553-1-git-send-email-yu-cheng.yu@intel.com
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/kernel/fpu/core.c | 16 ++++++++--------
+ 1 file changed, 8 insertions(+), 8 deletions(-)
+
+diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
+index 3fc03a09a93b1710..c289e2f4a6e5b464 100644
+--- a/arch/x86/kernel/fpu/core.c
++++ b/arch/x86/kernel/fpu/core.c
+@@ -517,14 +517,14 @@ void fpu__clear(struct fpu *fpu)
+ {
+ WARN_ON_FPU(fpu != &current->thread.fpu); /* Almost certainly an anomaly */
+
+- if (!use_eager_fpu() || !static_cpu_has(X86_FEATURE_FPU)) {
+- /* FPU state will be reallocated lazily at the first use. */
+- fpu__drop(fpu);
+- } else {
+- if (!fpu->fpstate_active) {
+- fpu__activate_curr(fpu);
+- user_fpu_begin();
+- }
++ fpu__drop(fpu);
++
++ /*
++ * Make sure fpstate is cleared and initialized.
++ */
++ if (static_cpu_has(X86_FEATURE_FPU)) {
++ fpu__activate_curr(fpu);
++ user_fpu_begin();
+ copy_init_fpstate_to_fpregs();
+ }
+ }
+--
+2.10.2
+