lkml.org 
[lkml]   [2014]   [Apr]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH RESEND 1/2] tracing: syscall_*regfunc() can race with copy_process()
On 04/10, Steven Rostedt wrote:
>
> On Wed, 9 Apr 2014 19:05:42 +0200
> Oleg Nesterov <oleg@redhat.com> wrote:
>
> > --- a/kernel/fork.c
> > +++ b/kernel/fork.c
> > @@ -1472,7 +1472,9 @@ static struct task_struct *copy_process(unsigned long clone_flags,
> >
> > total_forks++;
> > spin_unlock(&current->sighand->siglock);
> > + syscall_tracepoint_update(p);
> > write_unlock_irq(&tasklist_lock);
> > +
>
> So this looks to be a fix that probably should go to stable?

Not sure, this is up to you.

> > @@ -732,33 +732,31 @@ static int sys_tracepoint_refcount;
> >
> > void syscall_regfunc(void)
> > {
> > - unsigned long flags;
> > struct task_struct *g, *t;
> >
> > if (!sys_tracepoint_refcount) {
> > - read_lock_irqsave(&tasklist_lock, flags);
> > + read_lock(&tasklist_lock);
> > do_each_thread(g, t) {
> > /* Skip kernel threads. */
> > - if (t->mm)
> > + if (!(t->flags & PF_KTHREAD))
> > set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT);
> > } while_each_thread(g, t);
> > - read_unlock_irqrestore(&tasklist_lock, flags);
> > + read_unlock(&tasklist_lock);
> > }
> > sys_tracepoint_refcount++;
> > }
> >
> > void syscall_unregfunc(void)
> > {
> > - unsigned long flags;
> > struct task_struct *g, *t;
> >
> > sys_tracepoint_refcount--;
> > if (!sys_tracepoint_refcount) {
> > - read_lock_irqsave(&tasklist_lock, flags);
> > + read_lock(&tasklist_lock);
> > do_each_thread(g, t) {
> > clear_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT);
> > } while_each_thread(g, t);
> > - read_unlock_irqrestore(&tasklist_lock, flags);
> > + read_unlock(&tasklist_lock);
>
> These changes should be in a separate patch, as they can wait till 3.16.

OK, I'll split this change.

Oleg.



\
 
 \ /
  Last update: 2014-04-10 16:01    [W:0.639 / U:0.080 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site