On 02/16, Rik van Riel wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > On 02/16/2015 04:09 PM, Borislav Petkov wrote: > > On Fri, Feb 06, 2015 at 03:02:00PM -0500, r...@redhat.com wrote: > >> From: Oleg Nesterov <o...@redhat.com> > > >> diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c > >> index fb4cb6adf225..51c465846f06 100644 --- > >> a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -663,7 > >> +663,7 @@ static void math_error(struct pt_regs *regs, int > >> error_code, int trapnr) /* * Save the info for the exception > >> handler and clear the error. */ - save_init_fpu(task); + > >> unlazy_fpu(task); > > > > Do I see it correctly that even with this there's a not-so-small > > hole *after* conditional_sti() and *before* unlazy_fpu() where > > caller can still get preempted? > > That's ok, the context switch will save the register contents > to memory in that case.
Yes, thanks. > At that point unlazy_fpu will potentially > do nothing, and the task will process the FPU context that was > saved to memory previously. Or, if __thread_has_fpu() will be true again, it will save the registers again. And this equally applies to any other user of unlazy_fpu(). Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
