On Mon, Sep 17, 2012 at 12:40:16PM -0700, Tejun Heo wrote: > On Fri, Sep 14, 2012 at 03:50:40PM -0700, Colin Cross wrote: > > This patch set fixes a reproducible crash I'm seeing on a 3.4.10 > > kernel. flush_kthread_worker (which is different from > > flush_kthread_work) is initializing a kthread_work and a completion on > > the stack, then queuing it and calling wait_for_completion. Once the > > completion is signaled, flush_kthread_worker exits and the stack > > region used by the kthread_work may be immediately reused by another > > object on the stack, but kthread_worker_fn continues accessing its > > work pointer: > > work->func(work); <- calls complete, > > effectively frees work > > smp_wmb(); /* wmb worker-b0 paired with flush-b1 */ > > work->done_seq = work->queue_seq; <- overwrites a > > new stack object > > smp_mb(); /* mb worker-b1 paired with flush-b0 */ > > if (atomic_read(&work->flushing)) > > wake_up_all(&work->done); <- or crashes here > > > > These patches fix the problem by not accessing work after work->func > > is called, and should be backported to stable. They apply cleanly to > > 3.4.10. Upstream commits are 9a2e03d8ed518a61154f18d83d6466628e519f94 > > and 46f3d976213452350f9d10b0c2780c2681f7075b. > > Yeah, you're right. I wonder why this didn't come up before. Greg, > can you please pick up these two commits? Ok, will do, thanks for letting me know. greg k-h -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
