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Message-ID: <20090528082113.GA9062@redhat.com>
Date: Thu, 28 May 2009 10:21:13 +0200
From: Oleg Nesterov <oleg@...hat.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Roland McGrath <roland@...hat.com>, linux-kernel@...r.kernel.org
Subject: [PATCH] ptrace: don't take tasklist to get/set ->last_siginfo
Change ptrace_getsiginfo/ptrace_setsiginfo to use lock_task_sighand()
without tasklist_lock. Perhaps it makes sense to make a singler helper
with "bool rw" argument.
Signed-off-by: Oleg Nesterov <oleg@...hat.com>
--- PTRACE/kernel/ptrace.c~SIGINFO 2009-05-28 10:03:01.000000000 +0200
+++ PTRACE/kernel/ptrace.c 2009-05-28 10:06:59.000000000 +0200
@@ -463,37 +463,33 @@ static int ptrace_setoptions
static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
{
+ unsigned long flags;
int error = -ESRCH;
- read_lock(&tasklist_lock);
- if (likely(child->sighand != NULL)) {
+ if (lock_task_sighand(child, &flags)) {
error = -EINVAL;
- spin_lock_irq(&child->sighand->siglock);
if (likely(child->last_siginfo != NULL)) {
*info = *child->last_siginfo;
error = 0;
}
- spin_unlock_irq(&child->sighand->siglock);
+ unlock_task_sighand(child, &flags);
}
- read_unlock(&tasklist_lock);
return error;
}
static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
{
+ unsigned long flags;
int error = -ESRCH;
- read_lock(&tasklist_lock);
- if (likely(child->sighand != NULL)) {
+ if (lock_task_sighand(child, &flags)) {
error = -EINVAL;
- spin_lock_irq(&child->sighand->siglock);
if (likely(child->last_siginfo != NULL)) {
*child->last_siginfo = *info;
error = 0;
}
- spin_unlock_irq(&child->sighand->siglock);
+ unlock_task_sighand(child, &flags);
}
- read_unlock(&tasklist_lock);
return error;
}
--
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