On Fri, Feb 13, 2009 at 06:41:35AM +0000, Al Viro wrote: Aaaargh... /* * We don't have to hold all of the locks at the * same time here because we know that we're the * last reference to mnt and that no new writers * can come in. */ for_each_possible_cpu(cpu) { struct mnt_writer *cpu_writer = &per_cpu(mnt_writers, cpu); if (cpu_writer->mnt != mnt) continue; spin_lock(&cpu_writer->lock); is *almost* OK. Modulo SMP cache coherency. We know that nothing should be setting ->mnt to ours anymore, that's fine. But we do not know if we'd seen *earlier* change done on CPU in question (not the one we are running __mntput() on). I probably would still like to use milder solution in the long run, but for now let's check if turning that into struct mnt_writer *cpu_writer = &per_cpu(mnt_writers, cpu); spin_lock(&cpu_writer->lock); if (cpu_writer->mnt != mnt) { spin_unlock(&cpu_writer->lock); continue; } prevents the problem, OK? _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers