From 51c61a2838c33dab7b6659b9a3e008bb1b40bc9b Mon Sep 17 00:00:00 2001
From: Matt Renzelmann <mjr@cs.wisc.edu>
Date: Fri, 13 Apr 2012 07:59:40 +0000
Subject: ks8851: Fix missing mutex_lock/unlock
Move the ks8851_rdreg16 call above the call to request_irq and cache
the result for subsequent repeated use. A spurious interrupt may
otherwise cause a crash. Thanks to Stephen Boyd, Flavio Leitner, and
Ben Hutchings for feedback.
Signed-off-by: Matt Renzelmann <mjr@cs.wisc.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/net/ethernet/micrel/ks8851.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
(limited to 'drivers/net/ethernet/micrel/ks8851.c')
diff --git a/drivers/net/ethernet/micrel/ks8851.c b/drivers/net/ethernet/micrel/ks8851.c
index c722aa607d07..e5dc0757f077 100644
--- a/drivers/net/ethernet/micrel/ks8851.c
+++ b/drivers/net/ethernet/micrel/ks8851.c
@@ -1418,6 +1418,7 @@ static int __devinit ks8851_probe(struct spi_device *spi)
struct net_device *ndev;
struct ks8851_net *ks;
int ret;
+ unsigned cider;
ndev = alloc_etherdev(sizeof(struct ks8851_net));
if (!ndev)
@@ -1484,8 +1485,8 @@ static int __devinit ks8851_probe(struct spi_device *spi)
ks8851_soft_reset(ks, GRR_GSR);
/* simple check for a valid chip being connected to the bus */
-
- if ((ks8851_rdreg16(ks, KS_CIDER) & ~CIDER_REV_MASK) != CIDER_ID) {
+ cider = ks8851_rdreg16(ks, KS_CIDER);
+ if ((cider & ~CIDER_REV_MASK) != CIDER_ID) {
dev_err(&spi->dev, "failed to read device ID\n");
ret = -ENODEV;
goto err_id;
@@ -1516,8 +1517,7 @@ static int __devinit ks8851_probe(struct spi_device *spi)
}
netdev_info(ndev, "revision %d, MAC %pM, IRQ %d, %s EEPROM\n",
- CIDER_REV_GET(ks8851_rdreg16(ks, KS_CIDER)),
- ndev->dev_addr, ndev->irq,
+ CIDER_REV_GET(cider), ndev->dev_addr, ndev->irq,
ks->rc_ccr & CCR_EEPROM ? "has" : "no");
return 0;
--
cgit v1.2.3
From c5a99937a9cf74a623384023201a7d98b51e7e3b Mon Sep 17 00:00:00 2001
From: Stephen Boyd <sboyd@codeaurora.org>
Date: Wed, 18 Apr 2012 17:25:58 +0000
Subject: ks8851: Fix mutex deadlock in ks8851_net_stop()
There is a potential deadlock scenario when the ks8851 driver
is removed. The interrupt handler schedules a workqueue which
acquires a mutex that ks8851_net_stop() also acquires before
flushing the workqueue. Previously lockdep wouldn't be able
to find this problem but now that it has the support we can
trigger this lockdep warning by rmmoding the driver after
an ifconfig up.
Fix the possible deadlock by disabling the interrupts in
the chip and then release the lock across the workqueue
flushing. The mutex is only there to proect the registers
anyway so this should be ok.
=======================================================
[ INFO: possible circular locking dependency detected ]
3.0.21-00021-g8b33780-dirty #2911
-------------------------------------------------------
rmmod/125 is trying to acquire lock:
((&ks->irq_work)){+.+...}, at: [<c019e0b8>] flush_work+0x0/0xac
but task is already holding lock:
(&ks->lock){+.+...}, at: [<bf00b850>] ks8851_net_stop+0x64/0x138 [ks8851]
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&ks->lock){+.+...}:
[<c01b89c8>] __lock_acquire+0x940/0x9f8
[<c01b9058>] lock_acquire+0x10c/0x130
[<c083dbec>] mutex_lock_nested+0x68/0x3dc
[<bf00bd48>] ks8851_irq_work+0x24/0x46c [ks8851]
[<c019c580>] process_one_work+0x2d8/0x518
[<c019cb98>] worker_thread+0x220/0x3a0
[<c01a2ad4>] kthread+0x88/0x94
[<c0107008>] kernel_thread_exit+0x0/0x8
-> #0 ((&ks->irq_work)){+.+...}:
[<c01b7984>] validate_chain+0x914/0x1018
[<c01b89c8>] __lock_acquire+0x940/0x9f8
[<c01b9058>] lock_acquire+0x10c/0x130
[<c019e104>] flush_work+0x4c/0xac
[<bf00b858>] ks8851_net_stop+0x6c/0x138 [ks8851]
[<c06b209c>] __dev_close_many+0x98/0xcc
[<c06b2174>] dev_close_many+0x68/0xd0
[<c06b22ec>] rollback_registered_many+0xcc/0x2b8
[<c06b2554>] rollback_registered+0x28/0x34
[<c06b25b8>] unregister_netdevice_queue+0x58/0x7c
[<c06b25f4>] unregister_netdev+0x18/0x20
[<bf00c1f4>] ks8851_remove+0x64/0xb4 [ks8851]
[<c049ddf0>] spi_drv_remove+0x18/0x1c
[<c0468e98>] __device_release_driver+0x7c/0xbc
[<c0468f64>] driver_detach+0x8c/0xb4
[<c0467f00>] bus_remove_driver+0xb8/0xe8
[<c01c1d20>] sys_delete_module+0x1e8/0x27c
[<c0105ec0>] ret_fast_syscall+0x0/0x3c
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&ks->lock);
lock((&ks->irq_work));
lock(&ks->lock);
lock((&ks->irq_work));
*** DEADLOCK ***
4 locks held by rmmod/125:
#0: (&__lockdep_no_validate__){+.+.+.}, at: [<c0468f44>] driver_detach+0x6c/0xb4
#1: (&__lockdep_no_validate__){+.+.+.}, at: [<c0468f50>] driver_detach+0x78/0xb4
#2: (rtnl_mutex){+.+.+.}, at: [<c06b25e8>] unregister_netdev+0xc/0x20
#3: (&ks->lock){+.+...}, at: [<bf00b850>] ks8851_net_stop+0x64/0x138 [ks8851]
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/net/ethernet/micrel/ks8851.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
(limited to 'drivers/net/ethernet/micrel/ks8851.c')
diff --git a/drivers/net/ethernet/micrel/ks8851.c b/drivers/net/ethernet/micrel/ks8851.c
index e5dc0757f077..ad10759e3459 100644
--- a/drivers/net/ethernet/micrel/ks8851.c
+++ b/drivers/net/ethernet/micrel/ks8851.c
@@ -889,16 +889,17 @@ static int ks8851_net_stop(struct net_device *dev)
netif_stop_queue(dev);
mutex_lock(&ks->lock);
+ /* turn off the IRQs and ack any outstanding */
+ ks8851_wrreg16(ks, KS_IER, 0x0000);
+ ks8851_wrreg16(ks, KS_ISR, 0xffff);
+ mutex_unlock(&ks->lock);
/* stop any outstanding work */
flush_work(&ks->irq_work);
flush_work(&ks->tx_work);
flush_work(&ks->rxctrl_work);
- /* turn off the IRQs and ack any outstanding */
- ks8851_wrreg16(ks, KS_IER, 0x0000);
- ks8851_wrreg16(ks, KS_ISR, 0xffff);
-
+ mutex_lock(&ks->lock);
/* shutdown RX process */
ks8851_wrreg16(ks, KS_RXCR1, 0x0000);
@@ -907,6 +908,7 @@ static int ks8851_net_stop(struct net_device *dev)
/* set powermode to soft power down to save power */
ks8851_set_powermode(ks, PMECR_PM_SOFTDOWN);
+ mutex_unlock(&ks->lock);
/* ensure any queued tx buffers are dumped */
while (!skb_queue_empty(&ks->txq)) {
@@ -918,7 +920,6 @@ static int ks8851_net_stop(struct net_device *dev)
dev_kfree_skb(txb);
}
- mutex_unlock(&ks->lock);
return 0;
}
--
cgit v1.2.3
From e8195b24feb208f6e944e7542779f4397776794d Mon Sep 17 00:00:00 2001
From: Matt Renzelmann <mjr@cs.wisc.edu>
Date: Thu, 19 Apr 2012 07:17:17 +0000
Subject: ks8851: Fix request_irq/free_irq mismatch
The dev_id parameter passed to free_irq needs to match the one passed
to the corresponding request_irq.
Signed-off-by: Matt Renzelmann <mjr@cs.wisc.edu>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/net/ethernet/micrel/ks8851.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
(limited to 'drivers/net/ethernet/micrel/ks8851.c')
diff --git a/drivers/net/ethernet/micrel/ks8851.c b/drivers/net/ethernet/micrel/ks8851.c
index ad10759e3459..f8dda009d3c0 100644
--- a/drivers/net/ethernet/micrel/ks8851.c
+++ b/drivers/net/ethernet/micrel/ks8851.c
@@ -1525,7 +1525,7 @@ static int __devinit ks8851_probe(struct spi_device *spi)
err_netdev:
- free_irq(ndev->irq, ndev);
+ free_irq(ndev->irq, ks);
err_id:
err_irq:
--
cgit v1.2.3