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(PPS) with ESMTPS id 4149pgkpw2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 23 Aug 2024 20:43:41 +0100 (BST) Received: from pps.filterd (prod-mail-ppoint3.akamai.com [127.0.0.1]) by prod-mail-ppoint3.akamai.com (8.18.1.2/8.18.1.2) with ESMTP id 47NJcsLA014518; Fri, 23 Aug 2024 15:43:40 -0400 Received: from prod-mail-relay18.dfw02.corp.akamai.com ([172.27.165.172]) by prod-mail-ppoint3.akamai.com (PPS) with ESMTP id 4138s0j8m5-1; Fri, 23 Aug 2024 15:43:40 -0400 Received: from [100.64.0.1] (unknown [172.27.166.123]) by prod-mail-relay18.dfw02.corp.akamai.com (Postfix) with ESMTP id 21329389; Fri, 23 Aug 2024 19:43:37 +0000 (GMT) Message-ID: Date: Fri, 23 Aug 2024 12:43:36 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net 1/1] tcp: check skb is non-NULL in tcp_rto_delta_us() To: Eric Dumazet , Neal Cardwell Cc: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20240823033444.1257321-1-johunt@akamai.com> <20240823033444.1257321-2-johunt@akamai.com> Content-Language: en-US From: Josh Hunt In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.680,FMLib:17.12.28.16 definitions=2024-08-23_16,2024-08-23_01,2024-05-17_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 spamscore=0 adultscore=0 phishscore=0 suspectscore=0 bulkscore=0 malwarescore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2407110000 definitions=main-2408230144 X-Proofpoint-ORIG-GUID: PdfIPermMux2ctHnFxdM7MvTKlUUrNhv X-Proofpoint-GUID: PdfIPermMux2ctHnFxdM7MvTKlUUrNhv X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.680,FMLib:17.12.28.16 definitions=2024-08-23_16,2024-08-23_01,2024-05-17_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 phishscore=0 mlxscore=0 spamscore=0 clxscore=1011 impostorscore=0 priorityscore=1501 lowpriorityscore=0 bulkscore=0 mlxlogscore=964 malwarescore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2407110000 definitions=main-2408230145 On 8/22/24 11:55 PM, Eric Dumazet wrote: > !-------------------------------------------------------------------| > This Message Is From an External Sender > This message came from outside your organization. > |-------------------------------------------------------------------! > > On Fri, Aug 23, 2024 at 5:34 AM Josh Hunt wrote: >> >> There have been multiple occassions where we have crashed in this path >> because packets_out suggested there were packets on the write or retransmit >> queues, but in fact there weren't leading to a NULL skb being dereferenced. >> While we should fix that root cause we should also just make sure the skb >> is not NULL before dereferencing it. Also add a warn once here to capture >> some information if/when the problem case is hit again. >> >> Signed-off-by: Josh Hunt > > Hi Josh > > We do not want a patch series of one patch, with the stack trace in > the cover letter. > Please send a standalone patch, with all the information in its changelog. > > 1) Add Neal Cardwell in the CC list. > > 2) Are you using TCP_REPAIR by any chance ? > > 3) Please double check your kernel has these fixes. > > commit 1f85e6267caca44b30c54711652b0726fadbb131 tcp: do not send > empty skb from tcp_write_xmit() > commit 0c175da7b0378445f5ef53904247cfbfb87e0b78 tcp: prohibit > TCP_REPAIR_OPTIONS if data was already sent > Thanks Eric. I will resend and also check the commits you mentioned. I didn't include the writeup in the patch submission b/c it was rather long and detailed, but will include it in a v2. Josh