[PATCH] uml: use correct register file size everywhere
This patch uses MAX_REG_NR consistently to refer to the register file size.
FRAME_SIZE isn't sufficient because on x86_64, it is smaller than the
ptrace register file size. MAX_REG_NR was introduced as a consistent way
to get the number of registers, but wasn't used everywhere it should be.
When this causes a problem, it makes PTRACE_SETREGS fail on x86_64 because
of a corrupted segment register value in the known-good register file. The
patch also adds a register dump at that point in case there are any future
problems here.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/os-Linux/skas/mem.c b/arch/um/os-Linux/skas/mem.c
index b3c11cf..9383e87 100644
--- a/arch/um/os-Linux/skas/mem.c
+++ b/arch/um/os-Linux/skas/mem.c
@@ -48,7 +48,7 @@
static inline long do_syscall_stub(struct mm_id * mm_idp, void **addr)
{
unsigned long regs[MAX_REG_NR];
- int n;
+ int n, i;
long ret, offset;
unsigned long * data;
unsigned long * syscall;
@@ -66,9 +66,13 @@
(unsigned long) &__syscall_stub_start);
n = ptrace_setregs(pid, regs);
- if(n < 0)
+ if(n < 0){
+ printk("Registers - \n");
+ for(i = 0; i < MAX_REG_NR; i++)
+ printk("\t%d\t0x%lx\n", i, regs[i]);
panic("do_syscall_stub : PTRACE_SETREGS failed, errno = %d\n",
- n);
+ -n);
+ }
wait_stub_done(pid, 0, "do_syscall_stub");