Messages in this thread | | | Date | Thu, 10 Apr 2014 15:34:35 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH RESEND 1/2] tracing: syscall_*regfunc() can race with copy_process() |
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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(¤t->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.
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