Re: [PATCH net v3 2/2] net: ngbe: clear DRV_LOAD bit when ngbe_open() fails

[Joe Damato <joe@dama.to>]

On Wed, Sep 30, 2026 at 05:47:48PM +0800, Zhang Yunfei wrote:
> On NCSI-managed systems, a failed ifup - for example when IRQ or
> ring allocation fails under memory pressure - leaves the port
> without either host or firmware driving it: the firmware already
> handed the port over on open, so out-of-band management of the NIC
> through that port stops until the next successful ifup.
> 
> ngbe_open() sets the WX_CFG_PORT_CTL_DRV_LOAD bit to tell the
> management firmware the host has taken over the port, but every
> error path returns without clearing it, leaving rings, IRQs and the
> PHY torn down while the firmware still believes the host owns the
> port.
> 
> Roll the bit back on all open error paths, matching ngbe_close()
> and ngbe_dev_shutdown(), so a failed ifup leaves the same
> firmware-visible state as if the interface had never been opened.
> 
> Found by manual code inspection of the open error paths. The
> deterministic reproduction uses a loadable test module injecting a
> wx_setup_resources() failure: in a QEMU VM the unfixed driver
> leaves DRV_LOAD set after a failed open, and with the fix the bit
> is cleared. No physical ngbe device is involved.
> 
> Fixes: a1cf597b99a7 ("net: ngbe: Add ngbe mdio bus driver.")
> Cc: stable@vger.kernel.org
> Signed-off-by: Zhang Yunfei <zhangyunfei1@kylinos.cn>
> ---
> Changes in v3:
> - correct the Fixes tag to a1cf597b99a7, the commit that introduced
>   the bug (the first ngbe_open() failure path after the DRV_LOAD bit
>   is set; v2 pointed at e7956139a6cf, which added more failing returns
>   but not the first one); no code change.
> 
>  drivers/net/ethernet/wangxun/ngbe/ngbe_main.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

idk much about these devices but the reasoning and code looks right to me
after reading it so:

Reviewed-by: Joe Damato <joe@dama.to>