On 11/30/2017 11:15 PM, akpm@xxxxxxxxxxxxxxxxxxxx wrote: > From: Yisheng Xie <xieyisheng1@xxxxxxxxxx> > Subject: mm/mempolicy: add nodes_empty check in SYSC_migrate_pages > > As in manpage of migrate_pages, the errno should be set to EINVAL when > none of the node IDs specified by new_nodes are on-line and allowed by the > process's current cpuset context, or none of the specified nodes contain > memory. However, when test by following case: > > new_nodes = 0; > old_nodes = 0xf; > ret = migrate_pages(pid, old_nodes, new_nodes, MAX); > > The ret will be 0 and no errno is set. As the new_nodes is empty, we > should expect EINVAL as documented. > > To fix the case like above, this patch check whether target nodes AND > current task_nodes is empty, and then check whether AND > node_states[N_MEMORY] is empty. > > Link: http://lkml.kernel.org/r/1510882624-44342-4-git-send-email-xieyisheng1@xxxxxxxxxx > Signed-off-by: Yisheng Xie <xieyisheng1@xxxxxxxxxx> > Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx> > Cc: Chris Salls <salls@xxxxxxxxxxx> > Cc: Christopher Lameter <cl@xxxxxxxxx> > Cc: David Rientjes <rientjes@xxxxxxxxxx> > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> > Cc: Tan Xiaojun <tanxiaojun@xxxxxxxxxx> > Cc: Vlastimil Babka <vbabka@xxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> My previous concerns here were a mistake as I explained in my reply to v4. So you can add Acked-by: Vlastimil Babka <vbabka@xxxxxxx> and proceed with the series. Thanks. > --- > > mm/mempolicy.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff -puN mm/mempolicy.c~mm-mempolicy-add-nodes_empty-check-in-sysc_migrate_pages mm/mempolicy.c > --- a/mm/mempolicy.c~mm-mempolicy-add-nodes_empty-check-in-sysc_migrate_pages > +++ a/mm/mempolicy.c > @@ -1433,10 +1433,14 @@ SYSCALL_DEFINE4(migrate_pages, pid_t, pi > goto out_put; > } > > - if (!nodes_subset(*new, node_states[N_MEMORY])) { > - err = -EINVAL; > + task_nodes = cpuset_mems_allowed(current); > + nodes_and(*new, *new, task_nodes); > + if (nodes_empty(*new)) > + goto out_put; > + > + nodes_and(*new, *new, node_states[N_MEMORY]); > + if (nodes_empty(*new)) > goto out_put; > - } > > err = security_task_movememory(task); > if (err) > _ > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
