From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frederic Weisbecker Date: Sat, 17 Apr 2010 21:41:30 +0000 Subject: Re: [PATCH 7/7] sparc64: Add function graph tracer support. Message-Id: <20100417214128.GE15037@nowhere> List-Id: References: <20100412.234300.212396783.davem@davemloft.net> In-Reply-To: <20100412.234300.212396783.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: sparclinux@vger.kernel.org On Sat, Apr 17, 2010 at 02:38:37PM -0700, David Miller wrote: > From: Frederic Weisbecker > Date: Sat, 17 Apr 2010 23:34:15 +0200 > > > I haven't started the watchdog nor perf, I guess NMI don't trigger > > in other cases, right? > > They do, for the NMI watchdog, every few seconds. > > > For now, the only reentrancy I could find was irqs that interrupt > > the tracing path. Which means no good clue there. That said I > > have only logged recursivity on trace entry path, not yet > > on return. > > > > I'm disabling the protections on entry, just to narrow down > > the recursivity place, in case it only happens on return. > > No need to do so much work, when you hit this case simply > disable tracing and dump_stack(). That way you'll see it > clearly. This is what I'm doing. But I needed to know where the tracing recursion happens: on tracing entry or return. And obviously it looks like that only happens on return. And now I'm trying the dumps on return