diff options
| -rw-r--r-- | sys/amd64/amd64/machdep.c | 11 | ||||
| -rw-r--r-- | sys/i386/i386/machdep.c | 11 |
2 files changed, 18 insertions, 4 deletions
diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c index b5dd641..3516f1c 100644 --- a/sys/amd64/amd64/machdep.c +++ b/sys/amd64/amd64/machdep.c @@ -872,8 +872,15 @@ exec_setregs(td, entry, stack, ps_strings) /* reset %gs as well */ if (pcb == PCPU_GET(curpcb)) load_gs(_udatasel); - else - pcb->pcb_gs = _udatasel; + + /* + * Always reset pcb->pcb_gs to udatasel, it will be loaded into gs + * by cpu_switch_load_gs when this process returns from the system + * call. Failing to reset pcb_gs here can cause cpu_switch_load_gs + * to trigger a general protection fault if the parent process had + * modified gs to point at a LDT entry. + */ + pcb->pcb_gs = _udatasel; /* * Reset the hardware debug registers if they were in use. diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c index b5dd641..3516f1c 100644 --- a/sys/i386/i386/machdep.c +++ b/sys/i386/i386/machdep.c @@ -872,8 +872,15 @@ exec_setregs(td, entry, stack, ps_strings) /* reset %gs as well */ if (pcb == PCPU_GET(curpcb)) load_gs(_udatasel); - else - pcb->pcb_gs = _udatasel; + + /* + * Always reset pcb->pcb_gs to udatasel, it will be loaded into gs + * by cpu_switch_load_gs when this process returns from the system + * call. Failing to reset pcb_gs here can cause cpu_switch_load_gs + * to trigger a general protection fault if the parent process had + * modified gs to point at a LDT entry. + */ + pcb->pcb_gs = _udatasel; /* * Reset the hardware debug registers if they were in use. |
