Messages in this thread | | | Date | Fri, 8 Aug 2008 13:40:50 -0700 | From | "Paul E. McKenney" <> | Subject | Re: recent -git: BUG in free_thread_xstate |
| |
On Fri, Aug 08, 2008 at 08:46:21PM +0200, Vegard Nossum wrote: > On Fri, Aug 1, 2008 at 11:10 PM, Paul E. McKenney > <paulmck@linux.vnet.ibm.com> wrote: > > On Wed, Jul 23, 2008 at 01:31:09PM -0700, Suresh Siddha wrote: > >> On Wed, Jul 23, 2008 at 01:07:04PM -0700, Vegard Nossum wrote: > >> > Hi, > >> > > >> > I just got this on c010b2f76c3032e48097a6eef291d8593d5d79a6 (-git from > >> > yesterday): > >> > >> Do you see this in 2.6.26 aswell? I suspect it is coming from post 2.6.26 > >> changes. > >> > >> > > >> > BUG: unable to handle kernel paging request at 00664381 > >> > IP: [<c010b274>] free_thread_xstate+0x4/0x30 > >> ... > >> > >> > EIP is at arch/x86/kernel/process.c:36: > >> > > >> > if (tsk->thread.xstate) { > >> > > >> > >> It looks like the kernel stack of that process got corrupted, corrupting the > >> task pointer in thread_info. Can you send us your config file? > > > > I would also like to see the config file. > > Hi, > > I'm sorry for the late reply. > > I copied you because I saw some RCU entry in the stack trace, but it > is almost definitely not a problem with (core or "leaf") RCU code. > Sometimes it also happens that people will say "oh, I recognize this > problem, the patch has been posted here and here", etc. > > It seems to be a problem with either netpoll, netconsole, or the > 8139too driver. I find a UDP packet in the task_struct slab, and the > stacktrace with RCU entries come from unrelated, unfortunate callbacks > that stumbled upon the corruption. > > My config, if you are still interested, can be found here: > http://userweb.kernel.org/~vegard/bugs/20080724-fork/config > > I don't know if the problem persists with the latest -git, it is now a > while since I last tested, but I've checked kernels back to 2.6.20, so > the problem has existed for a long time.
Well, the config shows preemptable RCU, which was my concern at the time, but there was certainly no preemptable RCU in mainline in 2.6.20, so...
There -was- a bug in 2.6.26 release candidates that would cause RCU to fail badly on !HOTPLUG_CPU builds due to a failure to initialize, but that is fixed in 2.6.26 (thank you, Nick!!!).
Thanx, Paul
| |