The patch titled
Subject: kernel/notifier.c: double register detection
has been removed from the -mm tree. Its filename was
notifiers-double-register-detection.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Vasily Averin <vvs@xxxxxxxxxxxxx>
Subject: kernel/notifier.c: double register detection
By design notifiers can be registerd once only, 2nd register attempt
called by mistake silently corrupts notifiers list.
A few years ago I investigated described problem, the host was power
cycled because of notifier list corruption. I've prepared this patch and
applied it to the OpenVZ kernel and sent this patch but nobody commented
on it. Later it helped us to detect a similar problem in the OpenVz
kernel.
Mistakes with notifier registration can happen for example during
subsystem initialization from different namespaces, or because of a lost
unregister in the roll-back path on initialization failures.
The proposed check cannot prevent the described problem, however it allows
us to detect its reason quickly without coredump analysis.
Link: http://lkml.kernel.org/r/04127e71-4782-9bbb-fe5a-7c01e93a99b0@xxxxxxxxxxxxx
Signed-off-by: Vasily Averin <vvs@xxxxxxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/notifier.c | 1 +
1 file changed, 1 insertion(+)
--- a/kernel/notifier.c~notifiers-double-register-detection
+++ a/kernel/notifier.c
@@ -22,6 +22,7 @@ static int notifier_chain_register(struc
struct notifier_block *n)
{
while ((*nl) != NULL) {
+ WARN_ONCE(((*nl) == n), "double register detected");
if (n->priority > (*nl)->priority)
break;
nl = &((*nl)->next);
_
Patches currently in -mm which might be from vvs@xxxxxxxxxxxxx are
