3.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: Veaceslav Falico <vfalico@xxxxxxxxxx>
[ Upstream commit 3f315bef23075ea8a98a6fe4221a83b83456d970 ]
__netpoll_cleanup() is called in netconsole_netdev_event() while holding a
spinlock. Release/acquire the spinlock before/after it and restart the
loop. Also, disable the netconsole completely, because we won't have chance
after the restart of the loop, and might end up in a situation where
nt->enabled == 1 and nt->np.dev == NULL.
Signed-off-by: Veaceslav Falico <vfalico@xxxxxxxxxx>
Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
drivers/net/netconsole.c | 20 +++++++++-----------
1 file changed, 9 insertions(+), 11 deletions(-)
diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 01b104e..bff6908 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -630,6 +630,7 @@ static int netconsole_netdev_event(struct notifier_block *this,
goto done;
spin_lock_irqsave(&target_list_lock, flags);
+restart:
list_for_each_entry(nt, &target_list, list) {
netconsole_target_get(nt);
if (nt->np.dev == dev) {
@@ -642,20 +643,17 @@ static int netconsole_netdev_event(struct notifier_block *this,
case NETDEV_UNREGISTER:
/*
* rtnl_lock already held
+ * we might sleep in __netpoll_cleanup()
*/
- if (nt->np.dev) {
- spin_unlock_irqrestore(
- &target_list_lock,
- flags);
- __netpoll_cleanup(&nt->np);
- spin_lock_irqsave(&target_list_lock,
- flags);
- dev_put(nt->np.dev);
- nt->np.dev = NULL;
- }
+ spin_unlock_irqrestore(&target_list_lock, flags);
+ __netpoll_cleanup(&nt->np);
+ spin_lock_irqsave(&target_list_lock, flags);
+ dev_put(nt->np.dev);
+ nt->np.dev = NULL;
nt->enabled = 0;
stopped = true;
- break;
+ netconsole_target_put(nt);
+ goto restart;
}
}
netconsole_target_put(nt);
--
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