Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750981AbdLZN5h (ORCPT ); Tue, 26 Dec 2017 08:57:37 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:54732 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750705AbdLZN5g (ORCPT ); Tue, 26 Dec 2017 08:57:36 -0500 Date: Tue, 26 Dec 2017 14:57:37 +0100 From: Greg KH To: "Kohli, Gaurav" Cc: jslaby@suse.com, mikey@neuling.org, linux-kernel@vger.kernel.org Subject: Re: Query: Regarding crash in n_tty_receive_buf_common during boot Message-ID: <20171226135736.GA31138@kroah.com> References: <2cc97258-dbd1-c7fe-d9de-8e9f50449ea8@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <2cc97258-dbd1-c7fe-d9de-8e9f50449ea8@codeaurora.org> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4785 Lines: 99 On Tue, Dec 26, 2017 at 05:58:55PM +0530, Kohli, Gaurav wrote: > Hi , > We have seen lot of crashes in 4.9 during boot in n_tty_receive_buf_common, > when tty->disc_data > becomes NULL, Below is the call stack for same > 29.710969] PC is at n_tty_receive_buf_common+0x68/0xa3c > [?? 29.716425] LR is at n_tty_receive_buf_common+0x58/0xa3c > [?? 29.721882] pc : [] lr : [] pstate: > 80c00145 > [?? 29.721885] sp : ffffffc0a2b83c30 > [?? 29.721889] x29: ffffffc0a2b83c30 x28: ffffffc093c00080 > [?? 29.723875] x27: ffffff8009b7c0e8 x26: ffffff8009145000 > [?? 29.729218] x25: ffffff8009cdd748 x24: ffffffc0ee040028 > [?? 29.729225] x23: ffffffc093c7f280 x22: 0000000000000000 > [?? 29.729231] x21: ffffffc0e3a5cf62 x20: 0000000000000032 > [?? 29.729238] x19: 0000000000000000 x18: 0000000000000000 > [?? 29.729245] x17: 0000000000000000 x16: 0000000000000000 > [?? 29.729252] x15: 0000000000000000 x14: ffffffc0fb3de310 > [?? 29.729259] x13: ffffffc0fb3de308 x12: 0000000000000000 > [?? 29.729265] x11: ffffffc0f641aa80 x10: 0000000000000b10 > [?? 29.729272] x9 : ffffffc0a2b83ce0 x8 : ffffffc0a2b91cf0 > [?? 29.729279] x7 : 7aa17304d29fd900 x6 : ffffff8009bef778 > [?? 29.729285] x5 : ffffff80085a7e24 x4 : 0000000000000001 > [?? 29.729292] x3 : 0000000000000032 x2 : 0000000000000000 > [?? 29.729581] x1 : 0000000000000000 x0 : 0000000000002260 > [?? 29.732927] > [?? 29.732927] PC: 0xffffff80085a7410: > [?? 29.738025] 7410? 9104e381 aa0103f6 aa0203f3 2a0303f4 b9009ba4 f90033a1 > d503201f aa1603e0 > [?? 29.740517] 7430? b9009fbf f941af96 d0005cfa 942acb7f 91174340 f90047a0 > d2844c00 8b160000 > [?? 29.743892] 7450? c8dffc03 f94002c2 52820000 b941eb81 4b020000 0b030000 > 361800e1 528aaac1 > [?? 29.749003] 7470? 11000800 72aaaaa1 9b217c01 d360fc21 4b807c20 51000400 > 52800001 6b1f001f > [?? 29.753967] > [?? 29.753967] LR: 0xffffff80085a7400: > [?? 29.759068] 7400? a90573fb aa0003fc aa0103f5 aa1e03e0 9104e381 aa0103f6 > aa0203f3 2a0303f4 > [?? 29.760110] 7420? b9009ba4 f90033a1 d503201f aa1603e0 b9009fbf f941af96 > d0005cfa 942acb7f > [?? 29.766051] 7440? 91174340 f90047a0 d2844c00 8b160000 c8dffc03 f94002c2 > 52820000 b941eb81 > [?? 29.773012] 7460? 4b020000 0b030000 361800e1 528aaac1 11000800 72aaaaa1 > 9b217c01 d360fc21 > [?? 29.779088] > [?? 29.779088] SP: 0xffffffc0a2b83bf0: > [?? 29.779092] 3bf0? 085a7440 ffffff80 a2b83c30 ffffffc0 085a7450 ffffff80 > 80c00145 00000000 > [?? 29.779113] 3c10? a2b83c30 ffffffc0 085a7440 ffffff80 ffffffff ffffffff > 09059d28 ffffff80 > [?? 29.779134] 3c30? a2b83cd0 ffffffc0 085a7e60 ffffff80 93c00080 ffffffc0 > e3a5ce80 ffffffc0 > [?? 29.779155] 3c50? ee040008 ffffffc0 ee040000 ffffffc0 93c7f280 ffffffc0 > ee040028 ffffffc0 > [?? 29.779177] Process kworker/u16:10 (pid: 1216, stack limit = > 0xffffffc0a2b80000) > [?? 29.779181] Call trace: > [?? 29.779186] Exception stack(0xffffffc0a2b83a40 to 0xffffffc0a2b83b70) > [?? 29.779191] 3a40: 0000000000000000 0000008000000000 ffffffc0a2b83c30 > ffffff80085a7450 > [?? 29.779195] 3a60: 0000000080c00145 ffffffc0a2b83ba0 ffffffc0a2b91180 > ffffffc0a2b91180 > [?? 29.787281] 3a80: ffffff8009cdd6d0 ffffff80080f6ff8 ffffffc0a2b83aa0 > ffffff8008088e88 > [?? 29.787285] 3aa0: ffffffc0a2b83ab0 ffffff8008155758 ffffffc0a2b83ae0 > ffffff8008183760 > [?? 29.787289] 3ac0: ffffffc0a2b91180 ffffffc0f66781b0 ffffffc0f41be520 > ffffffc0f41be540 > [?? 29.787293] 3ae0: ffffffc0a2b83b10 ffffff800818cd50 ffffffc0f41be480 > 7aa17304d29fd900 > [?? 29.795323] 3b00: 0000000000002260 0000000000000000 0000000000000000 > 0000000000000032 > [?? 29.795327] 3b20: 0000000000000001 ffffff80085a7e24 ffffff8009bef778 > 7aa17304d29fd900 > [?? 29.803361] 3b40: ffffffc0a2b91cf0 ffffffc0a2b83ce0 0000000000000b10 > ffffffc0f641aa80 > [?? 29.803364] 3b60: 0000000000000000 ffffffc0fb3de308 > [?? 29.808376] [] n_tty_receive_buf_common+0x68/0xa3c > [?? 29.814893] [] n_tty_receive_buf2+0x3c/0x48 > [?? 29.820791] [] flush_to_ldisc+0xe4/0x124 > [?? 29.820798] [] process_one_work+0x184/0x480 > [?? 29.826696] [] worker_thread+0x140/0x4b4 > [?? 29.826701] [] kthread+0xf4/0x108 > I have seen some earlier patch which is fixing the same > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=71472fa9c52b1da27663c275d416d8654b905f05 > > but it is reverted finally in below commit: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=71472fa9c52b1da27663c275d416d8654b905f05. > Do we have any fix available for above bug, please revert me for any further > information. Nope, no new information, see the archives for details :) But have you tried 4.14? It might be better in this area... good luck! greg k-h