From patchwork Fri Oct 10 14:23:42 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 5066221 Return-Path: X-Original-To: patchwork-ocfs2-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 80EEFC11AC for ; Fri, 10 Oct 2014 14:29:42 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 9253B2021A for ; Fri, 10 Oct 2014 14:29:41 +0000 (UTC) Received: from userp1040.oracle.com (userp1040.oracle.com [156.151.31.81]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 705F220204 for ; Fri, 10 Oct 2014 14:29:40 +0000 (UTC) Received: from acsinet21.oracle.com (acsinet21.oracle.com [141.146.126.237]) by userp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id s9AETQbl023888 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 10 Oct 2014 14:29:27 GMT Received: from oss.oracle.com (oss-external.oracle.com [137.254.96.51]) by acsinet21.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id s9AETPnX021220 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 10 Oct 2014 14:29:25 GMT Received: from localhost ([127.0.0.1] helo=oss.oracle.com) by oss.oracle.com with esmtp (Exim 4.63) (envelope-from ) id 1Xcb96-0001NO-EC; Fri, 10 Oct 2014 07:26:16 -0700 Received: from ucsinet21.oracle.com ([156.151.31.93]) by oss.oracle.com with esmtp (Exim 4.63) (envelope-from ) id 1Xcb78-00015b-6n for ocfs2-devel@oss.oracle.com; Fri, 10 Oct 2014 07:24:14 -0700 Received: from userp1030.oracle.com (userp1030.oracle.com [156.151.31.80]) by ucsinet21.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id s9AEODmQ026532 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 10 Oct 2014 14:24:13 GMT Received: from aserp2030.oracle.com (aserp2030.oracle.com [141.146.126.74]) by userp1030.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id s9AEOCHQ007192 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Fri, 10 Oct 2014 14:24:13 GMT Received: from pps.filterd (aserp2030.oracle.com [127.0.0.1]) by aserp2030.oracle.com (8.14.7/8.14.7) with SMTP id s9AENwnO009263 for ; Fri, 10 Oct 2014 14:24:12 GMT Received: from mx2.suse.de (cantor2.suse.de [195.135.220.15]) by aserp2030.oracle.com with ESMTP id 1pxb5c57w2-1 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NOT) for ; Fri, 10 Oct 2014 14:24:12 +0000 Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 73AC6ADF8; Fri, 10 Oct 2014 14:24:04 +0000 (UTC) Received: by quack.suse.cz (Postfix, from userid 1000) id 0992D82059; Fri, 10 Oct 2014 16:24:01 +0200 (CEST) From: Jan Kara To: linux-fsdevel@vger.kernel.org Date: Fri, 10 Oct 2014 16:23:42 +0200 Message-Id: <1412951028-4085-38-git-send-email-jack@suse.cz> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1412951028-4085-1-git-send-email-jack@suse.cz> References: <1412951028-4085-1-git-send-email-jack@suse.cz> X-ServerName: cantor2.suse.de X-Proofpoint-Virus-Version: vendor=nai engine=5600 definitions=7586 signatures=670543 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 suspectscore=1 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=7.0.1-1402240000 definitions=main-1410100121 Cc: Dave Kleikamp , jfs-discussion@lists.sourceforge.net, tytso@mit.edu, Jeff Mahoney , Mark Fasheh , Dave Chinner , reiserfs-devel@vger.kernel.org, xfs@oss.sgi.com, cluster-devel@redhat.com, Jan Kara , linux-ext4@vger.kernel.org, Steven Whitehouse , ocfs2-devel@oss.oracle.com, viro@zeniv.linux.org.uk Subject: [Ocfs2-devel] [PATCH] x86: Fixup lockdep complaint caused by io apic code X-BeenThere: ocfs2-devel@oss.oracle.com X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: ocfs2-devel-bounces@oss.oracle.com Errors-To: ocfs2-devel-bounces@oss.oracle.com X-Source-IP: acsinet21.oracle.com [141.146.126.237] X-Spam-Status: No, score=-5.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 0day kernel testing guys have reported following lockdep complaint: ====================================================== [ INFO: possible circular locking dependency detected ] 3.15.0-rc5-00567-gbafe980 #1 Not tainted ------------------------------------------------------- swapper/1 is trying to acquire lock: (&irq_desc_lock_class){-.-...}, at: [<8107dc8c>] __irq_get_desc_lock+0x3c/0x70 but task is already holding lock: (&port_lock_key){......}, at: [<815f5b27>] serial8250_startup+0x337/0x720 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&port_lock_key){......}: lock when printing to serial console> [<810750e5>] lock_acquire+0x85/0x190 [<81baed9d>] _raw_spin_lock_irqsave+0x4d/0x60 [<8106eb1c>] down_trylock+0xc/0x30 [<8107b795>] console_trylock+0x15/0xb0 [<8107be8f>] vprintk_emit+0x14f/0x4d0 [<81b969b9>] printk+0x38/0x3a [<82137f78>] print_ICs+0x5b/0x3e7 [<8212bb41>] do_one_initcall+0x8b/0x128 [<8212bd7d>] kernel_init_freeable+0x19f/0x236 [<81b9238b>] kernel_init+0xb/0xd0 [<81bb0080>] ret_from_kernel_thread+0x20/0x30 -> #1 (i8259A_lock){-.....}: [<810750e5>] lock_acquire+0x85/0x190 [<81baed9d>] _raw_spin_lock_irqsave+0x4d/0x60 [<81005af1>] unmask_8259A_irq+0x11/0x60 [<81005b4b>] enable_8259A_irq+0xb/0x10 [<8107fffb>] irq_enable+0x2b/0x40 [<8108005d>] irq_startup+0x4d/0x60 [<8107f2bc>] __setup_irq+0x39c/0x460 [<8107f433>] setup_irq+0x33/0x80 [<8212db15>] setup_default_timer_irq+0xf/0x11 [<8212db2d>] hpet_time_init+0x16/0x18 [<8212daff>] x86_late_time_init+0x9/0x10 [<8212ba3d>] start_kernel+0x331/0x3aa [<8212b380>] i386_start_kernel+0x12e/0x131 -> #0 (&irq_desc_lock_class){-.-...}: [<810743c2>] __lock_acquire+0x19c2/0x1b20 [<810750e5>] lock_acquire+0x85/0x190 [<81baed9d>] _raw_spin_lock_irqsave+0x4d/0x60 [<8107dc8c>] __irq_get_desc_lock+0x3c/0x70 [<8107eb1e>] __disable_irq_nosync+0x1e/0x50 [<8107eb58>] disable_irq_nosync+0x8/0x10 [<815f5c78>] serial8250_startup+0x488/0x720 [<815f205e>] uart_startup.part.4+0x6e/0x1e0 [<815f2a40>] uart_open+0xe0/0x140 [<815e4b51>] tty_open+0x141/0x510 [<81118bc0>] chrdev_open+0x60/0x140 [<8111372c>] do_dentry_open+0x14c/0x230 [<8111459e>] finish_open+0x2e/0x40 [<8112132a>] do_last+0x4aa/0xd30 [<81121c5a>] path_openat+0xaa/0x610 [<811221ec>] do_filp_open+0x2c/0x70 [<81114a81>] do_sys_open+0x111/0x210 [<81114b9d>] SyS_open+0x1d/0x20 [<8212bda4>] kernel_init_freeable+0x1c6/0x236 [<81b9238b>] kernel_init+0xb/0xd0 [<81bb0080>] ret_from_kernel_thread+0x20/0x30 I believe the core of the problem is that print_PIC() calls printk() from under i8259A_lock. I've checked and that doesn't seem to happen anywhere else in the kernel. So let's move printk() from under that lock. As a side note this problem has existed for a long time but it was uncovered by my patch resulting in extended lockdep coverage of printk code. Reported-by: Jet Chen Signed-off-by: Jan Kara --- arch/x86/kernel/apic/io_apic.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index 6ad4658de705..b815a4c9e5e5 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -1770,7 +1770,7 @@ __apicdebuginit(void) print_local_APICs(int maxcpu) __apicdebuginit(void) print_PIC(void) { - unsigned int v; + unsigned int v0, v1, v2; unsigned long flags; if (!legacy_pic->nr_legacy_irqs) @@ -1780,24 +1780,23 @@ __apicdebuginit(void) print_PIC(void) raw_spin_lock_irqsave(&i8259A_lock, flags); - v = inb(0xa1) << 8 | inb(0x21); - printk(KERN_DEBUG "... PIC IMR: %04x\n", v); - - v = inb(0xa0) << 8 | inb(0x20); - printk(KERN_DEBUG "... PIC IRR: %04x\n", v); + v0 = inb(0xa1) << 8 | inb(0x21); + v1 = inb(0xa0) << 8 | inb(0x20); outb(0x0b,0xa0); outb(0x0b,0x20); - v = inb(0xa0) << 8 | inb(0x20); + v2 = inb(0xa0) << 8 | inb(0x20); outb(0x0a,0xa0); outb(0x0a,0x20); raw_spin_unlock_irqrestore(&i8259A_lock, flags); - printk(KERN_DEBUG "... PIC ISR: %04x\n", v); + printk(KERN_DEBUG "... PIC IMR: %04x\n", v0); + printk(KERN_DEBUG "... PIC IRR: %04x\n", v1); + printk(KERN_DEBUG "... PIC ISR: %04x\n", v2); - v = inb(0x4d1) << 8 | inb(0x4d0); - printk(KERN_DEBUG "... PIC ELCR: %04x\n", v); + v0 = inb(0x4d1) << 8 | inb(0x4d0); + printk(KERN_DEBUG "... PIC ELCR: %04x\n", v0); } static int __initdata show_lapic = 1;