From: David Christensen <drc@linux.vnet.ibm.com>
To: netdev@vger.kernel.org,
Siva Reddy Kallam <siva.kallam@broadcom.com>,
Prashant Sreedharan <prashant@broadcom.com>,
Michael Chan <mchan@broadcom.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] tg3: driver sleeps indefinitely when EEH errors exceed eeh_max_freezes
Date: Fri, 24 Jul 2020 17:19:23 -0700 [thread overview]
Message-ID: <4bb07889-063f-c12d-28e0-11de9766c774@linux.vnet.ibm.com> (raw)
In-Reply-To: <20200617185117.732849-1-drc@linux.vnet.ibm.com>
[-- Attachment #1: Type: text/plain, Size: 2772 bytes --]
> The driver function tg3_io_error_detected() calls napi_disable twice,
> without an intervening napi_enable, when the number of EEH errors exceeds
> eeh_max_freezes, resulting in an indefinite sleep while holding rtnl_lock.
>
> Add check for pcierr_recovery which skips code already executed for the
> "Frozen" state.
>
> Signed-off-by: David Christensen <drc@linux.vnet.ibm.com>
> ---
> drivers/net/ethernet/broadcom/tg3.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
> index 7a3b22b35238..ebff1fc0d8ce 100644
> --- a/drivers/net/ethernet/broadcom/tg3.c
> +++ b/drivers/net/ethernet/broadcom/tg3.c
> @@ -18168,8 +18168,8 @@ static pci_ers_result_t tg3_io_error_detected(struct pci_dev *pdev,
>
> rtnl_lock();
>
> - /* We probably don't have netdev yet */
> - if (!netdev || !netif_running(netdev))
> + /* Could be second call or maybe we don't have netdev yet */
> + if (!netdev || tp->pcierr_recovery || !netif_running(netdev))
> goto done;
>
> /* We needn't recover from permanent error */
>
It appears this change is not sufficient. There's another failure case
when a TX timeout occurs, causing tg3_reset_task() to run, followed by a
call to tg3_io_error_detected() by the EEH driver. Not all occurences
of this sequence cause a failure, but some do. Here's an abbreviated
version of tg3_reset_task():
static void tg3_reset_task(struct work_struct *work)
{
...
tg3_netif_stop(tp); /* >>> Calls tg3_napi_disable() */
tg3_full_lock(tp, 1);
if (tg3_flag(tp, TX_RECOVERY_PENDING)) {
tp->write32_tx_mbox = tg3_write32_tx_mbox;
tp->write32_rx_mbox = tg3_write_flush_reg32;
tg3_flag_set(tp, MBOX_WRITE_REORDER);
tg3_flag_clear(tp, TX_RECOVERY_PENDING);
}
tg3_halt(tp, RESET_KIND_SHUTDOWN, 0);
err = tg3_init_hw(tp, true);
if (err)
goto out;
tg3_netif_start(tp); /* >>> Calls tg3_napi_enable() */
out:
...
}
In the working case, tg3_init_hw() returns successfully, resulting in
every instance of napi_disable() being followed by an instance of
napi_enable().
In the failing case, tg3_hw_init() returns an error. (This is not
surprising since the system is now preventing the adapter from accessing
its MMIO registers. I'm curious why it doesn't always fail.) When
tg3_hw_init() fails, tg3_netif_start() is not called, and we end up with
two sequential calls to napi_disable(), resulting in multiple hung task
messages.
A more complete log file attached below.
Can you suggest another solution or does it make sense to reconsider my
v1 patch for the issue?
Dave
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[-- Type: application/zip, Size: 94194 bytes --]
next prev parent reply other threads:[~2020-07-25 0:19 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-15 19:01 [PATCH] tg3: driver sleeps indefinitely when EEH errors exceed eeh_max_freezes David Christensen
2020-06-15 20:45 ` Michael Chan
2020-06-15 22:21 ` David Christensen
2020-06-16 1:33 ` Michael Chan
2020-06-17 18:51 ` [PATCH v2] " David Christensen
2020-06-17 19:07 ` Michael Chan
2020-06-19 3:35 ` David Miller
2020-07-25 0:19 ` David Christensen [this message]
2020-07-27 7:26 ` Michael Chan
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