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Wylie" Cc: Holger =?iso-8859-1?Q?Hoffst=E4tte?= , Jamal Hadi Salim , regressions@lists.linux.dev, Jiri Pirko , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Octavian Purdila , Toke =?iso-8859-1?Q?H=F8iland-J=F8rgensen?= , stable@vger.kernel.org, Greg KH Subject: Re: [REGRESSION] 6.14.3 panic - kernel NULL pointer dereference in htb_dequeue Message-ID: References: <89301960-1758-5b2e-6d91-81ef06843e14@applied-asynchrony.com> <20250421210927.50d6a355@frodo.int.wylie.me.uk> <20250422175145.1cb0bd98@frodo.int.wylie.me.uk> <4e2a6522-d455-f0ce-c77d-b430c3047d7c@applied-asynchrony.com> <20250422214716.5e181523@frodo.int.wylie.me.uk> <20250423105131.7ab46a47@frodo.int.wylie.me.uk> <20250424135331.02511131@frodo.int.wylie.me.uk> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250424135331.02511131@frodo.int.wylie.me.uk> Hi Alan, On Thu, Apr 24, 2025 at 01:53:31PM +0100, Alan J. Wylie wrote: > > On Tue, Apr 22, 2025 at 07:20:24PM +0200, Holger Hoffstätte wrote: > > > Meanwhile, if you could provide a reliable (and ideally minimum) > > reproducer, it would help me a lot to debug. > > I've found a reproducer. Below is a stripped down version of the shell script > that I posted in my initial report. > > Running this in a 1 second loop is enough to cause the panic very quickly. > > It seems a bit of network traffic is needed, too. > I just tried your reproducer in my VM since I don't have pppoe setup, after running ping flood (ping -f) bidirectionally for ~10 minutes, I still didn't get any warning or crash. I also tried to reduce the bandwidth limit you set in your script to get traffic throttled, still no crash/warning. Note, I just used the latest -net, without applying any extra patch. Thanks!