This is the mail archive of the
systemtap@sourceware.org
mailing list for the systemtap project.
Re: [PATCH v2 2.6.38-rc8-tip 7/20] 7: uprobes: store/restore original instruction.
- From: Steven Rostedt <rostedt at goodmis dot org>
- To: Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>
- Cc: Stephen Wilson <wilsons at start dot ca>, Peter Zijlstra <peterz at infradead dot org>, Ingo Molnar <mingo at elte dot hu>, Linux-mm <linux-mm at kvack dot org>, Arnaldo Carvalho de Melo <acme at infradead dot org>, Linus Torvalds <torvalds at linux-foundation dot org>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Christoph Hellwig <hch at infradead dot org>, Andi Kleen <andi at firstfloor dot org>, Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>, Oleg Nesterov <oleg at redhat dot com>, LKML <linux-kernel at vger dot kernel dot org>, Jim Keniston <jkenisto at linux dot vnet dot ibm dot com>, Roland McGrath <roland at hack dot frob dot com>, SystemTap <systemtap at sources dot redhat dot com>, Andrew Morton <akpm at linux-foundation dot org>, "Paul E. McKenney" <paulmck at linux dot vnet dot ibm dot com>
- Date: Tue, 15 Mar 2011 09:47:59 -0400
- Subject: Re: [PATCH v2 2.6.38-rc8-tip 7/20] 7: uprobes: store/restore original instruction.
- References: <20110314133403.27435.7901.sendpatchset@localhost6.localdomain6> <20110314133522.27435.45121.sendpatchset@localhost6.localdomain6> <20110314180914.GA18855@fibrous.localdomain> <20110315092247.GW24254@linux.vnet.ibm.com>
On Tue, 2011-03-15 at 14:52 +0530, Srikar Dronamraju wrote:
> * Stephen Wilson <wilsons@start.ca> [2011-03-14 14:09:14]:
>
Nitpick:
> Guess checking for tsk != NULL would only help if and only if we are doing
> within rcu. i.e we have to change to something like this
>
tsk = NULL;
> rcu_read_lock()
> if (mm->owner) {
> get_task_struct(mm->owner)
> tsk = mm->owner;
> }
> rcu_read_unlock()
> if (!tsk)
> return ret;
>
> Agree?
Or:
rcu_read_lock();
tsk = mm->owner;
if (tsk)
get_task_struct(tsk);
rcu_read_unlock();
if (!tsk)
return ret;
Probably looks cleaner.
-- Steve