Re: [PATCH net v3] net: tg3: guard napi_disable and pci_disable_device calls

[ALOK TIWARI <alok.a.tiwari@oracle.com>]

On 5/26/2026 9:07 AM, Pavan Chebbi wrote:
> On Mon, May 25, 2026 at 3:19 PM Yury Murashka <yurypm@arista.com> wrote:
>>
>> During PCIe hot-plug events, uncorrectable errors can be reported and
>> AER recovery for the tg3 device is initiated by the AER kernel driver.
>> The tg3_io_error_detected function is the AER error recovery handler.
>>
>>  From tg3_io_error_detected, we call tg3_netif_stop->tg3_napi_disable->
>> napi_disable and return PCI_ERS_RESULT_NEED_RESET on non-fatal error.
>> We expect that during AER recovery tg3_io_slot_reset and tg3_io_resume
>> will be called. But AER error recovery can fail. For example, when one
>> of PCIe devices on the same bus reports PCI_ERS_RESULT_NO_AER_DRIVER.
>> As a result, tg3_io_slot_reset and tg3_io_resume are not called, PCIe
>> device is disabled and NAPI is disabled (pci_disable_device and
>> napi_disable are called from tg3_io_error_detected). Then we can try to
>> disable PCIe link and napi_disable will be called again:
>>
>>    napi_disable+0x1b/0x1b0
>>    tg3_napi_disable+0x89/0xa0 [tg3]
>>    tg3_netif_stop+0x37/0xe3 [tg3]
>>    tg3_stop+0x30/0x160 [tg3]
>>    tg3_close+0x2a/0x60 [tg3]
>>    __dev_close_many+0xad/0x130
>>    dev_close_many+0xb2/0x190
>>    unregister_netdevice_many_notify+0x19d/0xa00
>>    unregister_netdevice_queue+0xf8/0x140
>>    unregister_netdev+0x1c/0x30
>>    tg3_remove_one+0xaa/0x150 [tg3]
>>    pci_device_remove+0x42/0xb0
>>    device_release_driver_internal+0x19c/0x200
>>    pci_stop_bus_device+0x85/0xb0
>>    pci_stop_bus_device+0x2c/0xb0
>>    pci_stop_bus_device+0x2c/0xb0
>>    pci_stop_and_remove_bus_device+0x12/0x20
>>    pciehp_unconfigure_device+0x9f/0x160
>>    pciehp_disable_slot+0x67/0x100
>>    pciehp_handle_presence_or_link_change+0x77/0x350
>>
>> This is not expected by napi_disable and a thread can be locked in
>> napi_disable forever. We have pcierr_recovery to cover a similar issue,
>> but for fatal errors. We cannot reuse this flag because it is reset in
>> tg3_io_resume, but it is not called when AER recovery fails.
>>
>> Similarly, if an AER error is reported and tg3_io_error_detected calls
>> pci_disable_device, a subsequent device removal via tg3_remove_one or
>> tg3_shutdown will call pci_disable_device again for the already-disabled
>> device.
>>
>> Add a napi_enabled flag to struct tg3 to track whether napi_enable has
>> been called. Guard tg3_napi_disable() so it returns early if NAPI was
>> not previously enabled. Also guard pci_disable_device() calls in
>> tg3_remove_one() and tg3_shutdown() with pci_is_enabled() to avoid
>> disabling an already-disabled device.
>>
>> Fixes: b45aa2f6192e ("tg3: Add EEH support")
>> Signed-off-by: Yury Murashka <yurypm@arista.com>
>> ---
>>   drivers/net/ethernet/broadcom/tg3.c | 14 ++++++++++++--
>>   drivers/net/ethernet/broadcom/tg3.h |  1 +
>>   2 files changed, 13 insertions(+), 2 deletions(-)
>>
> 
> LGTM.
> Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
> nit: The revision-change log for the patch is missing..

It seems this patch addresses two separate issues in the AER recovery flow:

NAPI enable/disable state handling
PCI device enabled/disabled state handling

Would it make sense to split this into two patches?

Thanks,
Alok