Re: [PATCH v2] tg3: Disable tg3 device on system reboot to avoid triggering AER

On Fri, Aug 26, 2022 at 9:19 AM Eric Dumazet [off-list ref] wrote:

On Thu, Aug 25, 2022 at 5:25 PM Kai-Heng Feng
[off-list ref] wrote:

quoted

Commit d60cd06331a3 ("PM: ACPI: reboot: Use S5 for reboot") caused a
reboot hang on one Dell servers so the commit was reverted.

Someone managed to collect the AER log and it's caused by MSI:
[ 148.762067] ACPI: Preparing to enter system sleep state S5
[ 148.794638] {1}[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 5
[ 148.803731] {1}[Hardware Error]: event severity: recoverable
[ 148.810191] {1}[Hardware Error]: Error 0, type: fatal
[ 148.816088] {1}[Hardware Error]: section_type: PCIe error
[ 148.822391] {1}[Hardware Error]: port_type: 0, PCIe end point
[ 148.829026] {1}[Hardware Error]: version: 3.0
[ 148.834266] {1}[Hardware Error]: command: 0x0006, status: 0x0010
[ 148.841140] {1}[Hardware Error]: device_id: 0000:04:00.0
[ 148.847309] {1}[Hardware Error]: slot: 0
[ 148.852077] {1}[Hardware Error]: secondary_bus: 0x00
[ 148.857876] {1}[Hardware Error]: vendor_id: 0x14e4, device_id: 0x165f
[ 148.865145] {1}[Hardware Error]: class_code: 020000
[ 148.870845] {1}[Hardware Error]: aer_uncor_status: 0x00100000, aer_uncor_mask: 0x00010000
[ 148.879842] {1}[Hardware Error]: aer_uncor_severity: 0x000ef030
[ 148.886575] {1}[Hardware Error]: TLP Header: 40000001 0000030f 90028090 00000000
[ 148.894823] tg3 0000:04:00.0: AER: aer_status: 0x00100000, aer_mask: 0x00010000
[ 148.902795] tg3 0000:04:00.0: AER: [20] UnsupReq (First)
[ 148.910234] tg3 0000:04:00.0: AER: aer_layer=Transaction Layer, aer_agent=Requester ID
[ 148.918806] tg3 0000:04:00.0: AER: aer_uncor_severity: 0x000ef030
[ 148.925558] tg3 0000:04:00.0: AER: TLP Header: 40000001 0000030f 90028090 00000000

The MSI is probably raised by incoming packets, so power down the device
and disable bus mastering to stop the traffic, as user confirmed this
approach works.

In addition to that, be extra safe and cancel reset task if it's running.

Cc: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/all/b8db79e6857c41dab4ef08bdf826ea7c47e3bafc.1615947283.git.josef@toxicpanda.com/ (local)
BugLink: https://bugs.launchpad.net/bugs/1917471
Signed-off-by: Kai-Heng Feng <redacted>
---
v2:
 - Move tg3_reset_task_cancel() outside of rtnl_lock() to prevent
   deadlock.

It seems tg3_reset_task_cancel() is already called while rtnl is held/owned.
Should we worry about that ?

In this shutdown code path, if we cancel it before rtnl_lock(), the
TG3_FLAG_RESET_TASK_PENDING flag will be cleared and we will not try
to cancel it again later when rtnl_lock() is held.

But I agree that calling tg3_reset_task_cancel() under rtnl_lock can
potentially deadlock if the reset_task is scheduled and we wait for it
to finish.  That logic should be fixed separately.

quoted

 drivers/net/ethernet/broadcom/tg3.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index db1e9d810b416..89889d8150da1 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c

@@ -18076,16 +18076,20 @@ static void tg3_shutdown(struct pci_dev *pdev)
        struct net_device *dev = pci_get_drvdata(pdev);
        struct tg3 *tp = netdev_priv(dev);

+       tg3_reset_task_cancel(tp);
+
        rtnl_lock();
+
        netif_device_detach(dev);

        if (netif_running(dev))
                dev_close(dev);

-       if (system_state == SYSTEM_POWER_OFF)
-               tg3_power_down(tp);
+       tg3_power_down(tp);

        rtnl_unlock();
+
+       pci_disable_device(pdev);
 }

 /**
--

2.36.1