On Wed, 12 Dec 2007 16:32:51 -0500 Lee Schermerhorn <[EMAIL PROTECTED]> wrote:
> Just this afternoon, I hit a null pointer deref in > __mem_cgroup_remove_list() [called from mem_cgroup_uncharge() if I can > trust the stack trace] attempting to unmap a page for migration. I'm > just starting to investigate this. > > I'll replace the series I have [~V10] with V11r2 and continue testing in > anticipation of the day that we can get this into -mm. > Hi, Lee-san. Could you know what is the caller of page migration ? system call ? hot removal ? or some new thing ? Note: 2.6.24-rc4-mm1's cgroup/migration logic. In 2.6.24-rc4-mm1, in page migration, mem_cgroup_prepare_migration() increments page_cgroup's refcnt before calling try_to_unmap(). This extra refcnt guarantees the page_cgroup's refcnt will not drop to 0 in sequence of unmap_and_move() -> try_to_unmap() -> page_remove_rmap() -> mem_cgroup_unchage(). Thanks, -Kame -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
