[PATCH] x86-64: fix perms/range of vsyscall vma in /proc/*/maps
The final line of /proc/<pid>/maps on x86_64 for native 64-bit
tasks shows an incorrect ending address and incorrect permissions. There
is only a single page mapped in this vsyscall region, and it is accessible
for both read and execute.
The patch below fixes this. (Since 32-bit-compat tasks have a real vma
with correct perms/range, no change is necessary for that scenario.)
Before the patch, a "cat /proc/self/maps | tail -1" shows this:
ffffffffff600000-ffffffffffe00000 ---p 00000000 [...]
After the patch, this is the output:
ffffffffff600000-ffffffffff601000 r-xp 00000000 [...]
Signed-off-by: Ernie Petrides <petrides@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>
diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
index 4c0c00e..2968b90 100644
--- a/arch/x86_64/mm/init.c
+++ b/arch/x86_64/mm/init.c
@@ -730,14 +730,15 @@
__initcall(x8664_sysctl_init);
#endif
-/* A pseudo VMAs to allow ptrace access for the vsyscall page. This only
+/* A pseudo VMA to allow ptrace access for the vsyscall page. This only
covers the 64bit vsyscall page now. 32bit has a real VMA now and does
not need special handling anymore. */
static struct vm_area_struct gate_vma = {
.vm_start = VSYSCALL_START,
- .vm_end = VSYSCALL_END,
- .vm_page_prot = PAGE_READONLY
+ .vm_end = VSYSCALL_START + (VSYSCALL_MAPPED_PAGES << PAGE_SHIFT),
+ .vm_page_prot = PAGE_READONLY_EXEC,
+ .vm_flags = VM_READ | VM_EXEC
};
struct vm_area_struct *get_gate_vma(struct task_struct *tsk)