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authorIngo Molnar <mingo@elte.hu>2008-10-12 11:32:17 +0200
committerIngo Molnar <mingo@elte.hu>2008-10-12 11:32:17 +0200
commit206855c321adee56db3946ca09a5887cddb9d598 (patch)
tree13a2729d4d0e37170552bd9ad3c6bba71ba0c55c /kernel/exit.c
parente8d3f455de4f42d4bab2f6f1aeb2cf3bd18eb508 (diff)
parentcb58ffc3889f0545628f138f849e759a331b8ddc (diff)
Merge branch 'x86/urgent' into core/signal
Conflicts: arch/x86/kernel/signal_64.c
Diffstat (limited to 'kernel/exit.c')
-rw-r--r--kernel/exit.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 16395644a98..85a83c83185 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -583,8 +583,6 @@ mm_need_new_owner(struct mm_struct *mm, struct task_struct *p)
* If there are other users of the mm and the owner (us) is exiting
* we need to find a new owner to take on the responsibility.
*/
- if (!mm)
- return 0;
if (atomic_read(&mm->mm_users) <= 1)
return 0;
if (mm->owner != p)
@@ -627,6 +625,16 @@ retry:
} while_each_thread(g, c);
read_unlock(&tasklist_lock);
+ /*
+ * We found no owner yet mm_users > 1: this implies that we are
+ * most likely racing with swapoff (try_to_unuse()) or /proc or
+ * ptrace or page migration (get_task_mm()). Mark owner as NULL,
+ * so that subsystems can understand the callback and take action.
+ */
+ down_write(&mm->mmap_sem);
+ cgroup_mm_owner_callbacks(mm->owner, NULL);
+ mm->owner = NULL;
+ up_write(&mm->mmap_sem);
return;
assign_new_owner: