x86/ptrace: Fix regs_get_argument_nth() to add correct offset

Fix regs_get_argument_nth() to add correct offset bytes. Because
offset_of() returns offset in byte, the offset should be added
to char * instead of unsigned long *.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <20090910235306.22412.31613.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index a33a17d5d5c80145e1fc83983bbb4f00d408215a..caffb6809452f0a2da3de34fecf240c64dcb757e 100644 (file)
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -150,7 +150,7 @@ static const int arg_offs_table[] = {
 unsigned long regs_get_argument_nth(struct pt_regs *regs, unsigned int n)
 {
        if (n < ARRAY_SIZE(arg_offs_table))
-               return *((unsigned long *)regs + arg_offs_table[n]);
+               return *(unsigned long *)((char *)regs + arg_offs_table[n]);
        else {
                /*
                 * The typical case: arg n is on the stack.