Messages in this thread | | | From | Andi Kleen <> | Subject | Re: [RFC][PATCH] fix move/migrate_pages() race on task struct | Date | Thu, 23 Feb 2012 10:45:00 -0800 |
| |
Dave Hansen <dave@linux.vnet.ibm.com> writes:
> sys_move_pages() and sys_migrate_pages() are a pretty nice copy > and paste job of each other. They both take a pid, find the task > struct, and then grab a ref on the mm. They both also do an > rcu_read_unlock() after they've taken the mm and then proceed to > access 'task'. I think this is a bug in both cases.
Can we share code?
> > This patch takes the pid-to-task code along with the credential > and security checks in sys_move_pages() and sys_migrate_pages() > and consolidates them. It now takes a task reference in > the new function and requires the caller to drop it. I > believe this resolves the race.
Looks good to me.
Reviewed-by: Andi Kleen <ak@linux.intel.com>
BTW looks like we really need a better stress test for these syscalls.
-Andi
-- ak@linux.intel.com -- Speaking for myself only
| |