Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751001AbdLZM3C (ORCPT ); Tue, 26 Dec 2017 07:29:02 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:46184 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750781AbdLZM3A (ORCPT ); Tue, 26 Dec 2017 07:29:00 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org DFB8E60398 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=gkohli@codeaurora.org To: jslaby@suse.com, gregkh@linuxfoundation.org, mikey@neuling.org From: "Kohli, Gaurav" Subject: Query: Regarding crash in n_tty_receive_buf_common during boot Cc: linux-kernel@vger.kernel.org Message-ID: <2cc97258-dbd1-c7fe-d9de-8e9f50449ea8@codeaurora.org> Date: Tue, 26 Dec 2017 17:58:55 +0530 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4727 Lines: 97 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. Regards Gaurav -- Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.