The patch titled
lockdep: fix 8139too.c deadlock
has been added to the -mm tree. Its filename is
lockdep-fix-8139tooc-deadlock.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: lockdep: fix 8139too.c deadlock
From: Arjan van de Ven <arjan@xxxxxxxxxxxxx>
> stack backtrace:
> [<f9099d31>] rtl8139_start_xmit+0xd9/0xff [8139too]
> [<c11ad5ea>] netpoll_send_skb+0x98/0xea
This seems to be a real deadlock...
So netpoll_send_skb takes the _xmit_lock, which is all nitty gritty
but then rtl8139_start_xmit comes around while that lock is taken, and
does
spin_unlock_irq(&tp->lock);
which.. enables interrupts and softirqs; this is quite bad because the
xmit lock is taken in softirq context for the watchdog like this:
[<c1200376>] _spin_lock+0x23/0x32
[<c11af282>] dev_watchdog+0x14/0xb1
[<c101dab2>] run_timer_softirq+0xf2/0x14a
[<c101a691>] __do_softirq+0x55/0xb0
[<c1004a8d>] do_softirq+0x58/0xbd
Which would deadlock now that the spin_unlock_irq() has enabled
irqs/softirqs while the _xmit_lock is still held.
The patch below turns this into a irqsave/irqrestore pair so that
interrupts don't get enabled unconditionally.
Signed-off-by: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Jeff Garzik <jeff@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/net/8139too.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)
diff -puN drivers/net/8139too.c~lockdep-fix-8139tooc-deadlock drivers/net/8139too.c
--- a/drivers/net/8139too.c~lockdep-fix-8139tooc-deadlock
+++ a/drivers/net/8139too.c
@@ -1709,6 +1709,7 @@ static int rtl8139_start_xmit (struct sk
void __iomem *ioaddr = tp->mmio_addr;
unsigned int entry;
unsigned int len = skb->len;
+ unsigned long flags;
/* Calculate the next Tx descriptor entry. */
entry = tp->cur_tx % NUM_TX_DESC;
@@ -1725,7 +1726,7 @@ static int rtl8139_start_xmit (struct sk
return 0;
}
- spin_lock_irq(&tp->lock);
+ spin_lock_irqsave(&tp->lock, flags);
RTL_W32_F (TxStatus0 + (entry * sizeof (u32)),
tp->tx_flag | max(len, (unsigned int)ETH_ZLEN));
@@ -1736,7 +1737,7 @@ static int rtl8139_start_xmit (struct sk
if ((tp->cur_tx - NUM_TX_DESC) == tp->dirty_tx)
netif_stop_queue (dev);
- spin_unlock_irq(&tp->lock);
+ spin_unlock_irqrestore(&tp->lock, flags);
if (netif_msg_tx_queued(tp))
printk (KERN_DEBUG "%s: Queued Tx packet size %u to slot %d.\n",
_
Patches currently in -mm which might be from arjan@xxxxxxxxxxxxx are
origin.patch
put-a-comment-at-register_die_notifier-that-the-export-is-used.patch
lockdep-fix-8139tooc-deadlock.patch
debug-shared-irqs.patch
vdso-print-fatal-signals.patch
vdso-improve-print_fatal_signals-support-by-adding-memory-maps.patch
-
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