CVS commit: src/sys/arch/x86/x86

["Maxime Villard" <maxv%netbsd.org@localhost>]

Module Name:    src
Committed By:   maxv
Date:           Tue Jun 19 07:23:45 UTC 2018

Modified Files:
        src/sys/arch/x86/x86: vm_machdep.c

Log Message:
Explicitly clear l2's pcb_fpcpu when forking.

A context switch (preemption) could occur between

        fpusave_lwp(l1, true);
and
        memcpy(pcb2, pcb1, sizeof(struct pcb));

In this case, l1's FPU state is re-installed on the current CPU, and
pcb1->pcb_fpcpu becomes non NULL. While it's fine to have l1's state
installed, we don't want to indicate l2's state is installed too.

With lazy fpu this was not a problem, because the context-switch would
not re-install the state, so pcb1->pcb_fpcpu was NULL.

Should fix PR/53383.


To generate a diff of this commit:
cvs rdiff -u -r1.33 -r1.34 src/sys/arch/x86/x86/vm_machdep.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.