From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [Xenomai-core] [BUG] trunk: screwed Linux irq state From: Philippe Gerum In-Reply-To: <45D068C0.8090208@domain.hid> References: <45CF951B.8080404@domain.hid> <1171233732.5035.24.camel@domain.hid> <17871.41373.425284.839228@domain.hid> <1171237780.5035.30.camel@domain.hid> <17871.45750.434103.944040@domain.hid> <45CFB49F.1050000@domain.hid> <45CFBE7B.3050906@domain.hid> <45D05431.10409@domain.hid> <45D068C0.8090208@domain.hid> Content-Type: text/plain Date: Mon, 12 Feb 2007 14:46:37 +0100 Message-Id: <1171287998.5001.4.camel@domain.hid> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: Philippe Gerum Reply-To: rpm@xenomai.org List-Id: "Xenomai life and development \(bug reports, patches, discussions\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gilles Chanteperdrix Cc: Jan Kiszka , xenomai-core On Mon, 2007-02-12 at 14:16 +0100, Gilles Chanteperdrix wrote: > Jan Kiszka wrote: > > Jan Kiszka wrote: > > > >>2.6.19 didn't magically start to work as well. Instead I have a back > >>trace now, see attachment. > >> > >>I included a full set of 16k points, but the thrilling things are around > >>-73 to -25: Some Linux process with IRQs on gets preempted by an RT-IRQ > >>(RTnet NIC). That triggers an RT kernel thread to run for a while (RTnet > >>stack manager, prio 98). But when returning to Linux again, its IRQs > >>remain masked now. The reason must be that weird exception at -62. Don't > >>know where it comes from and why is there no report about THAT issue in > >>the kernel logs. > > > > > > The cause of this page fault will get tracked down later today, but the > > way it is handled already causes some doubts to me. To make discussion > > easier, here is the relevant excerpt from the trace: > > Maybe this fault is due to the No-cow patch ? Before the no-cow patch, > vmalloced areas were added to all processes page directories, now they > are added only to the page directories of processes with the VM_PINNED > flag. So, if ipipe_test_root tries to access some module memory area > over the context of a non-realtime thread, a fault will occur. > Yes, it's a minor fault occurring due to on-demand memory mapping, this is why we don't get any alarming message in the kernel log. -- Philippe.