diff options
| author | Jon Medhurst <tixy@linaro.org> | 2016-05-10 16:30:05 +0100 |
|---|---|---|
| committer | Amit Daniel Kachhap <amit.kachhap@arm.com> | 2018-07-10 15:33:06 +0530 |
| commit | acb260838f627dafd172ff412253326acd24c175 (patch) | |
| tree | 9e6cc25fed3b83763de905b696d1a1e4287b2025 | |
| parent | 43e3f2cbbf8fdc3629c3264bf762fe962e7f43ee (diff) | |
sky2: Check power state before trying to read stats
When the device is shutdown, the state change can trigger a notifier
which tries to gather network statistics by calling sky2_get_stats.
Unfortunately, this attempts to read registers in hardware which may
have been powered down leading to a bus abort (see below). Partially
workaround this by checking device power state in sky2_get_stats.
Unhandled fault: synchronous external abort (0x96000210) at 0xffffff800017a918
Internal error: : 96000210 [#1] PREEMPT SMP
CPU: 0 PID: 229 Comm: kworker/0:2 Not tainted 3.18.31-00004-g60c1593-dirty #2
Hardware name: ARM Juno development board (r2) (DT)
Workqueue: events linkwatch_event
task: ffffffc97665c0c0 ti: ffffffc9766e0000 task.ti: ffffffc9766e0000
PC is at sky2_get_stats+0x74/0x40c
LR is at sky2_get_stats+0x408/0x40c
Call trace:
[<ffffffc0005eb3b4>] sky2_get_stats+0x74/0x40c
[<ffffffc0007a8978>] dev_get_stats+0x68/0xd0
[<ffffffc0007b651c>] rtnl_fill_ifinfo+0x388/0x8e0
[<ffffffc0007b9764>] rtmsg_ifinfo+0x78/0x10c
[<ffffffc0007a34b4>] netdev_state_change+0x48/0x54
[<ffffffc0007bacfc>] linkwatch_do_dev+0x50/0x88
[<ffffffc0007bb004>] __linkwatch_run_queue+0x164/0x198
[<ffffffc0007bb068>] linkwatch_event+0x30/0x3c
[<ffffffc0000b7084>] process_one_work+0x150/0x458
[<ffffffc0000b74d8>] worker_thread+0x14c/0x47c
[<ffffffc0000bd1f0>] kthread+0xe0/0xf4
Signed-off-by: Jon Medhurst <tixy@linaro.org>
| -rw-r--r-- | drivers/net/ethernet/marvell/sky2.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/net/ethernet/marvell/sky2.c b/drivers/net/ethernet/marvell/sky2.c index 697d9b374f5e..77012649cb4e 100644 --- a/drivers/net/ethernet/marvell/sky2.c +++ b/drivers/net/ethernet/marvell/sky2.c @@ -3909,6 +3909,18 @@ static void sky2_get_stats(struct net_device *dev, unsigned int start; u64 _bytes, _packets; + /* Try and check if device if off. If it is, abort gathering stats as + * any attempt to read hardware registers will generate a bus fault. + * This test is hacky and racy as there's nothing stopping the device + * being powered off immediately after the test. + */ + if (hw->pdev->pm_cap) { + u16 pmcsr; + int ret = pci_read_config_word(hw->pdev, hw->pdev->pm_cap + PCI_PM_CTRL, &pmcsr); + if (ret || (pmcsr & PCI_PM_CTRL_STATE_MASK) > PCI_D2) + return; /* Can't read power state or it's state D3 (off) */ + } + do { start = u64_stats_fetch_begin_irq(&sky2->rx_stats.syncp); _bytes = sky2->rx_stats.bytes; |