From: Andrew Morton <akpm@linux-foundation.org>
To: David Miller <davem@davemloft.net>
Cc: compudj@google.com, mbligh@google.com,
linux-kernel@vger.kernel.org, ak@suse.de, paulus@samba.org,
tony.luck@intel.com, hskinnemoen@atmel.com
Subject: Re: Thread flags modified without set_thread_flag() (non atomically)
Date: Thu, 1 Mar 2007 00:17:08 -0800 [thread overview]
Message-ID: <20070301001708.900eb5e5.akpm@linux-foundation.org> (raw)
In-Reply-To: <20070228.222341.74751530.davem@davemloft.net>
On Wed, 28 Feb 2007 22:23:41 -0800 (PST) David Miller <davem@davemloft.net> wrote:
> > That all looks rather deliberate.
> >
> > > powerpc/kernel/process.c: t->flags ^= (_TIF_ABI_PENDING |
> > > _TIF_32BIT);
> > >
> > > ia64/kernel/mca.c: ti->flags = _TIF_MCA_INIT;
> > >
> > > avr32/kernel/ptrace.c: ti->flags |= _TIF_BREAKPOINT;
> >
> > No, I don't immediately see anything in the flush_old_exec() code path
> > which tells us that nobody else can look up this thread_info (or be holding
> > a ref to it) in this context.
>
> Provide the counter example, what other threads of control can modify
> relevant flags while a thread is exec()'ing? It's essentially frozen
> outside of these code paths, otherwise we wouldn't be able to make all
> of these modifications to the task state.
As Mathieu points out, resched_task(), perhaps. It can be called from interrupt.
next prev parent reply other threads:[~2007-03-01 8:17 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-26 20:10 Thread flags modified without set_thread_flag() (non atomically) Mathieu Desnoyers
2007-03-01 6:03 ` Andrew Morton
2007-03-01 6:23 ` David Miller
2007-03-01 8:17 ` Andrew Morton [this message]
2007-03-01 9:34 ` Haavard Skinnemoen
2007-03-01 9:45 ` Andrew Morton
2007-03-01 10:14 ` Haavard Skinnemoen
2007-03-01 15:13 ` Haavard Skinnemoen
2007-03-01 19:59 ` Mathieu Desnoyers
2007-03-01 22:41 ` Andrew Morton
2007-03-05 16:30 ` Kyle Moffett
2007-03-05 14:40 ` Andi Kleen
2007-03-05 22:04 ` Andrew Morton
2007-03-06 4:35 ` Mathieu Desnoyers
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