[PATCH v2 7/7] x86: copy_thread: don't nullify ->ptrace_bps twice

From: Oleg Nesterov
Date: Tue Sep 02 2014 - 14:00:29 EST


Both 32bit and 64bit versions of copy_thread() do memset(ptrace_bps)
twice for no reason, kill the 2nd memset().

Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
---
arch/x86/kernel/process_32.c | 4 +---
arch/x86/kernel/process_64.c | 2 --
2 files changed, 1 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index c73b3c1..8f3ebfe 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -138,6 +138,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,

p->thread.sp = (unsigned long) childregs;
p->thread.sp0 = (unsigned long) (childregs+1);
+ memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));

if (unlikely(p->flags & PF_KTHREAD)) {
/* kernel thread */
@@ -153,7 +154,6 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
childregs->cs = __KERNEL_CS | get_kernel_rpl();
childregs->flags = X86_EFLAGS_IF | X86_EFLAGS_FIXED;
p->thread.io_bitmap_ptr = NULL;
- memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
return 0;
}
*childregs = *current_pt_regs();
@@ -168,8 +168,6 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
tsk = current;
err = -ENOMEM;

- memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
-
if (unlikely(test_tsk_thread_flag(tsk, TIF_IO_BITMAP))) {
p->thread.io_bitmap_ptr = kmemdup(tsk->thread.io_bitmap_ptr,
IO_BITMAP_BYTES, GFP_KERNEL);
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 593257d..3ed4a68 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -192,8 +192,6 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
childregs->sp = sp;

err = -ENOMEM;
- memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
-
if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) {
p->thread.io_bitmap_ptr = kmemdup(me->thread.io_bitmap_ptr,
IO_BITMAP_BYTES, GFP_KERNEL);
--
1.5.5.1

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