From patchwork Wed Jun 30 09:14:08 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Colin Ian King X-Patchwork-Id: 1498815 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lists.ubuntu.com (client-ip=91.189.94.19; helo=huckleberry.canonical.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=) Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4GFFz14FDcz9sW6; Wed, 30 Jun 2021 19:14:21 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.86_2) (envelope-from ) id 1lyWIM-0006J7-Tk; Wed, 30 Jun 2021 09:14:10 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1lyWIL-0006J1-7h for kernel-team@lists.ubuntu.com; Wed, 30 Jun 2021 09:14:09 +0000 Received: from 1.general.cking.uk.vpn ([10.172.193.212] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.93) (envelope-from ) id 1lyWIK-0000Db-Vj; Wed, 30 Jun 2021 09:14:09 +0000 From: Colin King To: kernel-team@lists.ubuntu.com Subject: [PATCH][SRU][Groovy][Hirsute][Impish] UBUNTU: ubuntu-host: add generic lseek op Date: Wed, 30 Jun 2021 10:14:08 +0100 Message-Id: <20210630091408.10053-1-colin.king@canonical.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" From: Colin Ian King BugLink: https://bugs.launchpad.net/1934110 Currently the lseek op is null and seeking on the esm-token procfs file will cause an oops as detected by the stress-ng procfs stressor as shown by the following splat: [ 942.470568] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 942.471157] #PF: supervisor instruction fetch in kernel mode [ 942.471724] #PF: error_code(0x0010) - not-present page [ 942.472297] PGD 0 P4D 0 [ 942.472867] Oops: 0010 [#1] SMP PTI [ 942.473435] CPU: 2 PID: 5661 Comm: stress-ng Not tainted 5.13.0-9-generic #9 [ 942.474012] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 [ 942.474599] RIP: 0010:0x0 [ 942.475194] Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. [ 942.475792] RSP: 0018:ffffaacf80ff7eb8 EFLAGS: 00010246 [ 942.476383] RAX: 0000000000000000 RBX: ffff9eaa8a175240 RCX: 0000000000000001 [ 942.476986] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff9eaa838d5800 [ 942.477600] RBP: ffffaacf80ff7ed0 R08: 0000000000004000 R09: 0000000000000004 [ 942.478203] R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000000 [ 942.478800] R13: 0000000000000000 R14: ffffffffffffffea R15: ffff9eaa838d5800 [ 942.479399] FS: 00007f998d487f00(0000) GS:ffff9eaaffc80000(0000) knlGS:0000000000000000 [ 942.480006] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 942.480607] CR2: ffffffffffffffd6 CR3: 000000010a774002 CR4: 0000000000370ee0 [ 942.481219] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 942.481855] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 942.482458] Call Trace: [ 942.483052] proc_reg_llseek+0x4e/0x80 [ 942.483646] ? __fdget_pos+0x43/0x50 [ 942.484234] ksys_lseek+0x84/0xc0 [ 942.484815] __x64_sys_lseek+0x1a/0x20 [ 942.485412] do_syscall_64+0x61/0xb0 [ 942.485966] ? asm_exc_page_fault+0x8/0x30 [ 942.486476] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 942.486994] RIP: 0033:0x7f998d5c1cdb [ 942.487512] Code: ff ff c3 0f 1f 40 00 48 8b 15 89 81 0d 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb ba 0f 1f 00 f3 0f 1e fa b8 08 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 8b 15 59 81 0d 00 f7 d8 [ 942.488593] RSP: 002b:00007ffdf61c5328 EFLAGS: 00000246 ORIG_RAX: 0000000000000008 [ 942.489148] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f998d5c1cdb [ 942.489710] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004 [ 942.490252] RBP: 0000000000000004 R08: 000001785e4740dd R09: 0000562dbebb9e50 [ 942.490801] R10: 00007ffdf61c5300 R11: 0000000000000246 R12: 00007ffdf61c63f0 [ 942.491354] R13: 00007ffdf61c53f0 R14: 0000000000000003 R15: 00000000000001e9 Fix this by using the generic lseek operation. Fixes: 71adefd254f2 ("UBUNTU: Add ubuntu-host module") Signed-off-by: Colin Ian King Acked-by: Stefan Bader Acked-by: Tim Gardner --- ubuntu/ubuntu-host/ubuntu-host.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/ubuntu/ubuntu-host/ubuntu-host.c b/ubuntu/ubuntu-host/ubuntu-host.c index 1abd402..a4c0636 100644 --- a/ubuntu/ubuntu-host/ubuntu-host.c +++ b/ubuntu/ubuntu-host/ubuntu-host.c @@ -38,6 +38,8 @@ static ssize_t esm_token_write(struct file *f, const char __user *buf, static const struct proc_ops esm_token_fops = { .proc_read = esm_token_read, .proc_write = esm_token_write, + .proc_lseek = default_llseek, + }; static void ubuntu_host_cleanup(void)