Please disregard. Thanks! Alex Dowad On 13/03/15 20:14, Alex Dowad wrote:
'user_stack_size' is very misleading, since the argument is never used for the size of the user stack. Rather, it is an argument which is passed to the main function executed by a newly forked kernel thread. Hence, rename it to 'kthread_arg'. When forking a new user thread, the kernel thread arg was (uselessly) added to the new user stack pointer. This "worked", since the kernel thread arg is always zero when forking a user thread, but it was obviously not intended. Signed-off-by: Alex Dowad <alexinbeijing@xxxxxxxxx> --- arch/ia64/kernel/process.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c index b515149..d4a78da 100644 --- a/arch/ia64/kernel/process.c +++ b/arch/ia64/kernel/process.c @@ -300,7 +300,7 @@ ia64_load_extra (struct task_struct *task) }/*- * Copy the state of an ia-64 thread. + * Copy the architecture-specific state of an ia-64 thread. * * We get here through the following call chain: * @@ -332,7 +332,7 @@ ia64_load_extra (struct task_struct *task) */ int copy_thread(unsigned long clone_flags, - unsigned long user_stack_base, unsigned long user_stack_size, + unsigned long user_stack_base, unsigned long kthread_arg, struct task_struct *p) { extern char ia64_ret_from_clone; @@ -376,13 +376,14 @@ copy_thread(unsigned long clone_flags, ia64_drop_fpu(p); /* don't pick up stale state from a CPU's fph */if (unlikely(p->flags & PF_KTHREAD)) {+ /* kernel thread */ if (unlikely(!user_stack_base)) { /* fork_idle() called us */ return 0; } memset(child_stack, 0, sizeof(*child_ptregs) + sizeof(*child_stack)); child_stack->r4 = user_stack_base; /* payload */ - child_stack->r5 = user_stack_size; /* argument */ + child_stack->r5 = kthread_arg; /* * Preserve PSR bits, except for bits 32-34 and 37-45, * which we can't read. @@ -406,6 +407,8 @@ copy_thread(unsigned long clone_flags,return 0;} + + /* user thread */ stack = ((struct switch_stack *) regs) - 1; /* copy parent's switch_stack & pt_regs to child: */ memcpy(child_stack, stack, sizeof(*child_ptregs) + sizeof(*child_stack)); @@ -416,7 +419,7 @@ copy_thread(unsigned long clone_flags, if (clone_flags & CLONE_SETTLS) child_ptregs->r13 = regs->r16; /* see sys_clone2() in entry.S */ if (user_stack_base) { - child_ptregs->r12 = user_stack_base + user_stack_size - 16; + child_ptregs->r12 = user_stack_base - 16; child_ptregs->ar_bspstore = user_stack_base; child_ptregs->ar_rnat = 0; child_ptregs->loadrs = 0;
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