From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sami Farin Subject: Panic since 4.15.15 in tcp_retransmit_timer when doing ss -K Date: Fri, 13 Apr 2018 23:46:04 +0300 Message-ID: <20180413204604.mthx2rgraeigaa27@m.mifar.in> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: Linux Networking Mailing List Return-path: Received: from mifar.in ([46.101.129.31]:50810 "EHLO mifar.in" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751177AbeDMUyL (ORCPT ); Fri, 13 Apr 2018 16:54:11 -0400 Received: from mifar.in (unknown [109.204.157.218]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mifar.in", Issuer "mifar.in" (verified OK)) by mifar.in (Postfix) with ESMTPS id 853405FEF7 for ; Fri, 13 Apr 2018 23:46:06 +0300 (EEST) Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: I started getting this since 4.15.15. It's easy to trigger, for example I get new IP address via dhcp (NetworkManager), then ss -K the_old_ip_address . Happens on Ryzen and SandyBridge systems. My guess of the cause: commit 960058fe196397aecb16bb14e64980e265d2bc5e (didn't try reverting) BUG: unable to handle kernel NULL pointer dereference at 000030 IP: tcp_retransmit_skb+0x57/0xc0 PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 4.15.17+ #42 Hardware name: To Be Filled By O.E.M./To Be Filled By O.E.M./X370 Taichi, BIOS P4.60 03/02/2018 RIP: 0010:tcp_retransmit_skb+0x57/0xc0 RSP: 0018:ffff95b1dea03e00 EFLAGS: 00010206 RAX: 00000000fffffff5 RBX: ffff95b15876d000 RCX: 5 RDX: 5 RSI: 0 RDI: ffff95b115876d000 ... Call Trace: tcp_retransmit_timer tcp_write_timer_handler tcp_write_timer ? tcp_write_timer_handler expire_timers run_timer_softirq sched_clock sched_clock sched_clock_cpu irqtime_account_irq __do_softirq sched_clock irq_exit smp_apic_timer_interrupt apic_timer_interrupt -- Do what you love because life is too short for anything else.