From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760278AbcBYKML (ORCPT ); Thu, 25 Feb 2016 05:12:11 -0500 Received: from mail-wm0-f47.google.com ([74.125.82.47]:36155 "EHLO mail-wm0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750840AbcBYKMG (ORCPT ); Thu, 25 Feb 2016 05:12:06 -0500 Subject: BUG: unable to handle kernel paging request from pty_write [was: Linux 4.4.2] To: Greg KH , linux-kernel@vger.kernel.org, Andrew Morton , torvalds@linux-foundation.org, stable@vger.kernel.org References: <20160217203730.GA14820@kroah.com> Cc: lwn@lwn.net, Jiri Slaby , Peter Hurley From: Jiri Slaby X-Enigmail-Draft-Status: N1110 Message-ID: <56CED373.9060603@suse.cz> Date: Thu, 25 Feb 2016 11:12:03 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <20160217203730.GA14820@kroah.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/17/2016, 09:37 PM, Greg KH wrote: > I'm announcing the release of the 4.4.2 kernel. ... > Peter Hurley (4): > n_tty: Fix unsafe reference to "other" ldisc > tty: Wait interruptibly for tty lock on reopen > tty: Retry failed reopen if tty teardown in-progress > tty: Fix unsafe ldisc reference via ioctl(TIOCGETD) It seems like 4.4.2 schedules a tty flush work but the work is deleted meanwhile. This was trigerred by a gdb build on our servers [1]. Going to investigate further, if this doesn't ring a bell? [1] https://build.opensuse.org/package/live_build_log/openSUSE:Factory:Staging:I/gdb/standard/x86_64 kernel tried to execute NX-protected page - exploit attempt? (uid: 399) BUG: unable to handle kernel paging request at ffff88023fd40000 IP: [] 0xffff88023fd40000 PGD 2240067 PUD 23fced063 PMD 23fcee063 PTE 800000023fd40163 Oops: 0011 [#1] PREEMPT SMP Modules linked in: ata_generic ata_piix nls_iso8859_1 nls_cp437 vfat fat virtio_rng virtio_blk virtio_pci virtio k_ipv6 nf_defrag_ipv6 nf_conntrack btrfs xor raid6_pq reiserfs squashfs fuse dm_snapshot dm_bufio dm_mod binfmt_ misc loop sg CPU: 7 PID: 3127 Comm: gdb Not tainted 4.4.2-3-default #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20151112_172657-sheep25 04/01/2 014 task: ffff8801e43a4240 ti: ffff8800bb2a4000 task.ti: ffff8800bb2a4000 RIP: 0010:[] [] 0xffff88023fd40000 RSP: 0018:ffff8800bb2a7c50 EFLAGS: 00056686 RAX: 00000000bb37e180 RBX: 0000000000000001 RCX: 00000000ffffffff RDX: 0000000000000000 RSI: ffff88023fdd6e80 RDI: ffff88023fdd6e80 RBP: ffffffff810a535a R08: 0000000000000000 R09: 0000000000000020 R10: 0000000001b52cb0 R11: 0000000000000293 R12: 0000000000000046 R13: ffff8800bb37e180 R14: 0000000000016e80 R15: ffff8800bb2a7c80 FS: 00007fe3e4aba740(0000) GS:ffff88023fdc0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff88023fd40000 CR3: 00000002353cd000 CR4: 00000000000406e0 Stack: 000000008146e197 ffff88017ee19f00 ffff880234e26a08 ffff88017ed2a830 0000000000000005 0000000000010e30 ffff8800bb2a7c90 ffffffff810a5585 ffff8800bb2a7cc8 ffffffff81092fe1 0000000000000000 ffff88017ee19f00 Call Trace: Inexact backtrace: [] ? wake_up_process+0x15/0x20 [] ? insert_work+0x81/0xc0 [] ? __queue_work+0x24c/0x390 [] ? queue_work_on+0x27/0x40 [] ? tty_flip_buffer_push+0x2b/0x30 [] ? pty_write+0x4a/0x60 [] ? n_tty_write+0x1b6/0x4d0 [] ? __wake_up_sync+0x20/0x20 [] ? tty_write+0x1cb/0x2b0 [] ? n_tty_open+0xe0/0xe0 [] ? __vfs_write+0x28/0xf0 [] ? apparmor_file_permission+0x18/0x20 [] ? security_file_permission+0x3d/0xc0 [] ? rw_verify_area+0x4f/0xe0 [] ? vfs_write+0xa9/0x1a0 [] ? SyS_write+0x46/0xa0 [] ? entry_SYSCALL_64_fastpath+0x16/0x75 Code: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0 00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 RIP [] 0xffff88023fd40000 RSP CR2: ffff88023fd40000 ---[ end trace 14d86b882766d1bf ]--- thanks, -- js suse labs