Re: [PATCH 2/3] printk: Add %ptc to safely print a task's comm

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wed, 2011-05-11 at 17:33 +0800, AmÃrico Wang wrote:
> On Wed, May 11, 2011 at 8:23 AM, John Stultz <john.stultz@xxxxxxxxxx> wrote:
> > Acessing task->comm requires proper locking. However in the past
> > access to current->comm could be done without locking. This
> > is no longer the case, so all comm access needs to be done
> > while holding the comm_lock.
> >
> > In my attempt to clean up unprotected comm access, I've noticed
> > most comm access is done for printk output. To simpify correct
> > locking in these cases, I've introduced a new %ptc format,
> > which will safely print the corresponding task's comm.
> >
> > Example use:
> > printk("%ptc: unaligned epc - sending SIGBUS.\n", current);
> >
> 
> Why do you hide current->comm behide printk?
> How is this better than printk("%s: ....", task_comm(current)) ?

So to properly access current->comm, you need to hold the task-lock (or
with my new patch set, the comm_lock). Rather then adding locking to all
the call sites that printk("%s ...", current->comm), I'm suggesting we
add a new %ptc method which will handle the locking for you.

thanks
-john


--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxxx  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>


[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux]     [Linux OMAP]     [Linux MIPS]     [ECOS]     [Asterisk Internet PBX]     [Linux API]