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tg3: prevent ifup/ifdown during PCI error recovery
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The patch fixes race conditions between PCI error recovery callbacks and
potential ifup/ifdown.

First, if ifup (tg3_open) is called between tg3_io_error_detected() and
tg3_io_resume() then tp->timer is armed twice before expiry. Once during
tg3_open() and again during tg3_io_resume(). This results in BUG
at kernel/time/timer.c:945.

Second, if ifdown (tg3_close) is called between tg3_io_error_detected()
and tg3_io_resume() then tg3_napi_disable() is called twice without
a tg3_napi_enable between. Once during tg3_io_error_detected() and again
during tg3_close(). The tg3_io_resume() then hangs on rtnl_lock().

v2: Added logging messages per Prashant's request

Cc: Prashant Sreedharan <[email protected]>
Cc: Michael Chan <[email protected]>

Signed-off-by: Ivan Vecera <[email protected]>
Acked-by: Prashant Sreedharan <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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Ivan Vecera authored and davem330 committed Sep 2, 2014
1 parent 88e4194 commit 0486a06
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Showing 2 changed files with 17 additions and 0 deletions.
16 changes: 16 additions & 0 deletions drivers/net/ethernet/broadcom/tg3.c
Original file line number Diff line number Diff line change
Expand Up @@ -11617,6 +11617,12 @@ static int tg3_open(struct net_device *dev)
struct tg3 *tp = netdev_priv(dev);
int err;

if (tp->pcierr_recovery) {
netdev_err(dev, "Failed to open device. PCI error recovery "
"in progress\n");
return -EAGAIN;
}

if (tp->fw_needed) {
err = tg3_request_firmware(tp);
if (tg3_asic_rev(tp) == ASIC_REV_57766) {
Expand Down Expand Up @@ -11674,6 +11680,12 @@ static int tg3_close(struct net_device *dev)
{
struct tg3 *tp = netdev_priv(dev);

if (tp->pcierr_recovery) {
netdev_err(dev, "Failed to close device. PCI error recovery "
"in progress\n");
return -EAGAIN;
}

tg3_ptp_fini(tp);

tg3_stop(tp);
Expand Down Expand Up @@ -17561,6 +17573,7 @@ static int tg3_init_one(struct pci_dev *pdev,
tp->rx_mode = TG3_DEF_RX_MODE;
tp->tx_mode = TG3_DEF_TX_MODE;
tp->irq_sync = 1;
tp->pcierr_recovery = false;

if (tg3_debug > 0)
tp->msg_enable = tg3_debug;
Expand Down Expand Up @@ -18071,6 +18084,8 @@ static pci_ers_result_t tg3_io_error_detected(struct pci_dev *pdev,

rtnl_lock();

tp->pcierr_recovery = true;

/* We probably don't have netdev yet */
if (!netdev || !netif_running(netdev))
goto done;
Expand Down Expand Up @@ -18195,6 +18210,7 @@ static void tg3_io_resume(struct pci_dev *pdev)
tg3_phy_start(tp);

done:
tp->pcierr_recovery = false;
rtnl_unlock();
}

Expand Down
1 change: 1 addition & 0 deletions drivers/net/ethernet/broadcom/tg3.h
Original file line number Diff line number Diff line change
Expand Up @@ -3407,6 +3407,7 @@ struct tg3 {

struct device *hwmon_dev;
bool link_up;
bool pcierr_recovery;
};

/* Accessor macros for chip and asic attributes
Expand Down

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