The patch titled
taskstats: add_del_listener() should ignore !valid listeners
has been added to the -mm tree. Its filename is
taskstats-add_del_listener-should-ignore-valid-listeners.patch
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------------------------------------------------------
Subject: taskstats: add_del_listener() should ignore !valid listeners
From: Oleg Nesterov <oleg@xxxxxxxxxx>
When send_cpu_listeners() finds the orphaned listener it marks it as
!valid and drops listeners->sem. Before it takes this sem for writing,
s->pid can be reused and add_del_listener() can wrongly try to re-use this
entry.
Change add_del_listener() to check ->valid = T.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Reviewed-by: Vasiliy Kulikov <segoon@xxxxxxxxxxxx>
Acked-by: Balbir Singh <bsingharora@xxxxxxxxx>
Cc: Jerome Marchand <jmarchan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/taskstats.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN kernel/taskstats.c~taskstats-add_del_listener-should-ignore-valid-listeners kernel/taskstats.c
--- a/kernel/taskstats.c~taskstats-add_del_listener-should-ignore-valid-listeners
+++ a/kernel/taskstats.c
@@ -304,7 +304,7 @@ static int add_del_listener(pid_t pid, c
listeners = &per_cpu(listener_array, cpu);
down_write(&listeners->sem);
list_for_each_entry(s2, &listeners->list, list) {
- if (s2->pid == pid)
+ if (s2->pid == pid && s2->valid)
goto exists;
}
list_add(&s->list, &listeners->list);
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
linux-next.patch
proc_fork_connector-a-lockless-real_parent-usage-is-not-safe.patch
ipc-introduce-shm_rmid_forced-sysctl-testing.patch
taskstats-add_del_listener-shouldnt-use-the-wrong-node.patch
taskstats-add_del_listener-should-ignore-valid-listeners.patch
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