lguest: clear cached last cpu when guest_set_pgd() called.
commit v3.9-rc1-53-g6d0cda9 "lguest: cache last cpu we ran on." missed
one case, which causes a triple fault. The guest calls guest_set_pgd()
on the top page, and we carefully remap the Switcher text page. But
we didn't reset last_host_cpu, so map_switcher_in_guest() thinks
the guest's regs and IDT/GDT etc are already mapped.
Reported-by: Paul Bolle <pebolle@tiscali.nl>
Tested-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/lguest/page_tables.c b/drivers/lguest/page_tables.c
index 699187a..5b9ac32 100644
--- a/drivers/lguest/page_tables.c
+++ b/drivers/lguest/page_tables.c
@@ -1002,6 +1002,7 @@
kill_guest(&lg->cpus[0],
"Cannot populate switcher mapping");
}
+ lg->pgdirs[pgdir].last_host_cpu = -1;
}
}