On Thu, 19 Dec 2013, Dave Chinner wrote: > On Wed, Dec 18, 2013 at 07:24:46PM +0000, Christoph Lameter wrote: > > The counter increment in inode_lru_isolate is happening after > > spinlocks have been dropped with preemption on using __count_vm_events > > making counter increment races possible. > > That's a nasty, undocumented problem that __count_vm_events() has.
AFACIT that is a pretty well established and known issue. It only affects cases where the fallback code for the counter increments is used. > Nobody who is modifying the fs/inode.c code is likely to know about > this, so just moving the code under an unrelated lock is not > sufficient to prevent this from happening again. Hence I'd prefer > that you just change it to use count_vm_events() rather than try to > be tricksy by replacing the landmine in the code that we've already > stepped on once. I have a patchset here that is supposed to be merged soon that will detect these cases. Moving the code is IMHO the simplest solution. count_vm_events will have to disable interrupts on platforms that do not support fast RMV operations otherwise. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
