From ffdf91856c812646aa276711fa7e3ad80b00764a Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Wed, 26 May 2010 14:43:14 -0700 Subject: [PATCH] ia64: ptrace_attach_sync_user_rbs: avoid "task->signal != NULL" checks Preparation to make task->signal immutable, no functional changes. It doesn't matter which pointer we check under tasklist to ensure the task was not released, ->signal or ->sighand. But we are going to make ->signal refcountable, change the code to use ->sighand. Note: this code doesn't need this check and tasklist_lock at all, it should be converted to use lock_task_sighand(). And, the code under SIGNAL_STOP_STOPPED check looks wrong. Signed-off-by: Oleg Nesterov Cc: Fenghua Yu Cc: Roland McGrath Cc: Stanislaw Gruszka Cc: Tony Luck Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/ia64/kernel/ptrace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c index 0dec7f702448..7c7909f9bc93 100644 --- a/arch/ia64/kernel/ptrace.c +++ b/arch/ia64/kernel/ptrace.c @@ -638,7 +638,7 @@ ptrace_attach_sync_user_rbs (struct task_struct *child) */ read_lock(&tasklist_lock); - if (child->signal) { + if (child->sighand) { spin_lock_irq(&child->sighand->siglock); if (child->state == TASK_STOPPED && !test_and_set_tsk_thread_flag(child, TIF_RESTORE_RSE)) { @@ -662,7 +662,7 @@ ptrace_attach_sync_user_rbs (struct task_struct *child) * job control stop, so that SIGCONT can be used to wake it up. */ read_lock(&tasklist_lock); - if (child->signal) { + if (child->sighand) { spin_lock_irq(&child->sighand->siglock); if (child->state == TASK_TRACED && (child->signal->flags & SIGNAL_STOP_STOPPED)) { -- 2.20.1