From: Andrew Lunn <andrew@lunn.ch>
To: I Viswanath <viswanathiyyappan@gmail.com>
Cc: petkan@nucleusys.com, andrew+netdev@lunn.ch, davem@davemloft.net,
edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
linux-usb@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, skhan@linuxfoundation.org,
linux-kernel-mentees@lists.linux.dev,
david.hunter.linux@gmail.com,
syzbot+78cae3f37c62ad092caa@syzkaller.appspotmail.com
Subject: Re: [PATCH] net: usb: Remove disruptive netif_wake_queue in rtl8150_set_multicast
Date: Sat, 20 Sep 2025 17:30:36 +0200 [thread overview]
Message-ID: <5b51d80e-e67c-437d-a2fc-bebdf5e9a958@lunn.ch> (raw)
In-Reply-To: <20250920045059.48400-1-viswanathiyyappan@gmail.com>
On Sat, Sep 20, 2025 at 10:20:59AM +0530, I Viswanath wrote:
> syzbot reported WARNING in rtl8150_start_xmit/usb_submit_urb.
> This is a possible sequence of events:
>
> CPU0 (in rtl8150_start_xmit) CPU1 (in rtl8150_start_xmit) CPU2 (in rtl8150_set_multicast)
> netif_stop_queue();
> netif_stop_queue();
> usb_submit_urb();
> netif_wake_queue(); <-- Wakes up TX queue before it's ready
> netif_stop_queue();
> usb_submit_urb(); <-- Warning
> freeing urb
>
> Remove netif_wake_queue and corresponding netif_stop_queue in rtl8150_set_multicast to
> prevent this sequence of events
Please expand this sentence with an explanation of why this is
safe. Why are these two calls not needed? The original author of this
code thought they where needed, so you need to explain why they are
not needed.
Andrew
---
pw-bot: cr
next prev parent reply other threads:[~2025-09-20 15:31 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-20 4:50 [PATCH] net: usb: Remove disruptive netif_wake_queue in rtl8150_set_multicast I Viswanath
2025-09-20 15:30 ` Andrew Lunn [this message]
2025-09-20 16:52 ` viswanath
2025-09-20 17:28 ` Andrew Lunn
2025-09-20 18:18 ` [PATCH net v2] " I Viswanath
2025-09-23 1:07 ` Jakub Kicinski
2025-09-23 7:47 ` Michal Pecio
2025-09-23 14:28 ` Jakub Kicinski
2025-09-23 23:20 ` Michal Pecio
2025-09-23 23:37 ` Jakub Kicinski
2025-09-25 5:59 ` Deepak Sharma
2025-09-24 7:47 ` Michal Pecio
2025-09-24 8:02 ` viswanath
2025-09-24 9:36 ` Michal Pecio
2025-09-24 10:25 ` viswanath
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