Messages in this thread | | | Date | Wed, 16 Nov 2016 18:54:37 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH] x86/fpu: Fix invalid FPU ptrace state after execve |
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On Wed, Nov 16, 2016 at 08:56:36AM -0800, Yu-cheng Yu wrote: > 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 when eagerfpu is enabled, fpu__clear() did > not properly clear fpstate. Fix it by doing just that. > > Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> > Reported-by: Robert O'Callahan <robert@ocallahan.org> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: "H. Peter Anvin" <hpa@zytor.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: "Ravi V. Shankar" <ravi.v.shankar@intel.com> > --- > 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 4700401..4c203c4 100644 > --- a/arch/x86/kernel/fpu/core.c > +++ b/arch/x86/kernel/fpu/core.c > @@ -521,14 +521,14 @@ void fpu__clear(struct fpu *fpu) > { > WARN_ON_FPU(fpu != ¤t->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); > + > + /* > + * When eagerfpu is used, make sure fpstate is cleared and initialized. > + */ > + if (use_eager_fpu()) {
c592b5734706 ("x86/fpu: Remove use_eager_fpu()")
Please redo this patch against tip/master.
-- Regards/Gruss, Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --
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