On Fri, 6 Jul 2012, PRINGLE Chris wrote: > > Yes, I was able to reproduce the issue on 3.4.4-rt13. I ran a few tests under > > ftrace and got a bit more of information. > > > > The problem seems to happen in kmem_cache_free(), at this piece of code: > > > > local_lock_irqsave(slab_lock, flags); > > __cache_free(cachep, objp, __builtin_return_address(0)); > > unlock_slab_and_free_delayed(flags); > > > > It seems to fail at the local_lock_irqsave() statement with: > > > > [ 149.328013] kernel BUG at kernel/rtmutex.c:725! > > [ 149.328013] invalid opcode: 0000 [#1] PREEMPT SMP > > > > And by the end I see: > > > > [ 149.420228] note: insmod[2801] exited with preempt_count 1 > > Thanks for this. Any ideas where we might go from here? This used to > work in 2.6.33 but got broken between 2.6.33 and 3.0; unfortunately > there don't appear to be any RT patch releases between those two > versions so it's hard to see what might have been broken. > > It worries me a bit because this could potentially go wrong during > runtime if the kernel ever reaps the lookaside cache for memory; > this will then crash the entire system. Found the root cause, working on a fix. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
