Attached is a patch to fix the soft lockup problem when removing the
netconsole module.
It looks different than the original patch I posted because the context
had to change to maintain 80 column code. For reference the original
e-mail + patch was "[BUG] 2.6.21 hang in
cancel_rearming_delayed_workqueue()" sent on 5/25/07.
Jason.
>From 102a018d601e954f658d272d4daeef139ae40e0e Mon Sep 17 00:00:00 2001
From: Jason Wessel <[email protected]>
Date: Wed, 30 May 2007 08:03:52 -0500
Subject: [PATCH] The netpoll_cleanup handler can hang the kernel if there is no work in
the work queue because a call to cancel_rearming_delayed_work() with
no work goes into an infinite loop.
The typical case where this is a problem is on removing a kernel
module such as the netconsole driver or kgdboe.
To maintain 80 column code, the function had to have one level of braces
dropped.
Signed-off-by: Jason Wessel <[email protected]>
---
net/core/netpoll.c | 36 +++++++++++++++++++-----------------
1 files changed, 19 insertions(+), 17 deletions(-)
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 4581ece..28fa50e 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -766,30 +766,32 @@ void netpoll_cleanup(struct netpoll *np)
struct netpoll_info *npinfo;
unsigned long flags;
- if (np->dev) {
- npinfo = np->dev->npinfo;
- if (npinfo) {
- if (npinfo->rx_np == np) {
- spin_lock_irqsave(&npinfo->rx_lock, flags);
- npinfo->rx_np = NULL;
- npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
- spin_unlock_irqrestore(&npinfo->rx_lock, flags);
- }
+ if (!np->dev)
+ return;
+
+ npinfo = np->dev->npinfo;
+ if (npinfo) {
+ if (npinfo->rx_np == np) {
+ spin_lock_irqsave(&npinfo->rx_lock, flags);
+ npinfo->rx_np = NULL;
+ npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
+ spin_unlock_irqrestore(&npinfo->rx_lock, flags);
+ }
- np->dev->npinfo = NULL;
- if (atomic_dec_and_test(&npinfo->refcnt)) {
- skb_queue_purge(&npinfo->arp_tx);
- skb_queue_purge(&npinfo->txq);
+ np->dev->npinfo = NULL;
+ if (atomic_dec_and_test(&npinfo->refcnt)) {
+ skb_queue_purge(&npinfo->arp_tx);
+ skb_queue_purge(&npinfo->txq);
+ if (delayed_work_pending(&npinfo->tx_work)) {
cancel_rearming_delayed_work(&npinfo->tx_work);
flush_scheduled_work();
-
- kfree(npinfo);
}
- }
- dev_put(np->dev);
+ kfree(npinfo);
+ }
}
+ dev_put(np->dev);
np->dev = NULL;
}
--
1.5.0.6
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