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From: Michael Chan <michael.chan@broadcom.com>
Date: Fri, 8 Dec 2017 09:35:42 -0800
Message-ID: <CACKFLinnDFOMCE5cx7hXs6DjjKmG7Bb65Nc41oMkpLdKCqHrYA@mail.gmail.com>
Subject: Re: [PATCH] bnxt_en: Fix sources of spurious netpoll warnings
To: Calvin Owens <calvinowens@fb.com>
Cc: Netdev <netdev@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>, kernel-team@fb.com
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On Fri, Dec 8, 2017 at 9:05 AM, Calvin Owens <calvinowens@fb.com> wrote:
> After applying 2270bc5da3497945 ("bnxt_en: Fix netpoll handling") and
> 903649e718f80da2 ("bnxt_en: Improve -ENOMEM logic in NAPI poll loop."),
> we still see the following WARN fire:
>
>   ------------[ cut here ]------------
>   WARNING: CPU: 0 PID: 1875170 at net/core/netpoll.c:165 netpoll_poll_dev+0x15a/0x160
>   bnxt_poll+0x0/0xd0 exceeded budget in poll
>   <snip>
>   Call Trace:
>    [<ffffffff814be5cd>] dump_stack+0x4d/0x70
>    [<ffffffff8107e013>] __warn+0xd3/0xf0
>    [<ffffffff8107e07f>] warn_slowpath_fmt+0x4f/0x60
>    [<ffffffff8179519a>] netpoll_poll_dev+0x15a/0x160
>    [<ffffffff81795f38>] netpoll_send_skb_on_dev+0x168/0x250
>    [<ffffffff817962fc>] netpoll_send_udp+0x2dc/0x440
>    [<ffffffff815fa9be>] write_ext_msg+0x20e/0x250
>    [<ffffffff810c8125>] call_console_drivers.constprop.23+0xa5/0x110
>    [<ffffffff810c9549>] console_unlock+0x339/0x5b0
>    [<ffffffff810c9a88>] vprintk_emit+0x2c8/0x450
>    [<ffffffff810c9d5f>] vprintk_default+0x1f/0x30
>    [<ffffffff81173df5>] printk+0x48/0x50
>    [<ffffffffa0197713>] edac_raw_mc_handle_error+0x563/0x5c0 [edac_core]
>    [<ffffffffa0197b9b>] edac_mc_handle_error+0x42b/0x6e0 [edac_core]
>    [<ffffffffa01c3a60>] sbridge_mce_output_error+0x410/0x10d0 [sb_edac]
>    [<ffffffffa01c47cc>] sbridge_check_error+0xac/0x130 [sb_edac]
>    [<ffffffffa0197f3c>] edac_mc_workq_function+0x3c/0x90 [edac_core]
>    [<ffffffff81095f8b>] process_one_work+0x19b/0x480
>    [<ffffffff810967ca>] worker_thread+0x6a/0x520
>    [<ffffffff8109c7c4>] kthread+0xe4/0x100
>    [<ffffffff81884c52>] ret_from_fork+0x22/0x40
>
> This happens because we increment rx_pkts on -ENOMEM and -EIO, resulting
> in rx_pkts > 0. Fix this by only bumping rx_pkts if we were actually
> given a non-zero budget.
>
> Signed-off-by: Calvin Owens <calvinowens@fb.com>

Thanks.
Acked-by: Michael Chan <michael.chan@broadcom.com>