From mboxrd@z Thu Jan 1 00:00:00 1970 From: Francois Romieu Subject: Re: [Bug 42754] New: BUG: sleeping function called from invalid context at mm/memory.c:3924 Date: Fri, 10 Feb 2012 17:30:27 +0100 Message-ID: <20120210163027.GA29329@electric-eye.fr.zoreil.com> References: <20120209191317.2fbad57b.akpm@linux-foundation.org> <20120210122657.GA9347@smp.if.uj.edu.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andrew Morton , netdev@vger.kernel.org, bugzilla-daemon@bugzilla.kernel.org, Peter Zijlstra , Paul Gortmaker , Alan Cox To: Witold Baryluk Return-path: Received: from violet.fr.zoreil.com ([92.243.8.30]:45251 "EHLO violet.fr.zoreil.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758171Ab2BJQmj (ORCPT ); Fri, 10 Feb 2012 11:42:39 -0500 Content-Disposition: inline In-Reply-To: <20120210122657.GA9347@smp.if.uj.edu.pl> Sender: netdev-owner@vger.kernel.org List-ID: Witold Baryluk : > On 02-09 19:13, Andrew Morton wrote: [...] > https://bugzilla.kernel.org/show_bug.cgi?id=42754 For the sirdev part: [...] > [ 182.080017] -> #1 (&port_lock_key){..-...}: > [ 182.080017] [] check_prevs_add+0xcb/0x120 > [ 182.080017] [] validate_chain.isra.34+0x557/0x6d0 > [ 182.080017] [] __lock_acquire+0x355/0x820 > [ 182.080017] [] lock_acquire+0x87/0x1b0 > [ 182.080017] [] _raw_spin_lock_irqsave+0x5e/0xa0 > [ 182.080017] [] uart_write_room+0x22/0x60 > [ 182.080017] [] tty_write_room+0x19/0x20 > [ 182.080017] [] irtty_do_write+0x42/0xa0 [irtty_sir] > [ 182.080017] [] sirdev_hard_xmit+0xc5/0x280 [sir_dev] This is dev->drv->do_write in sirdev_hard_xmit. > [ 182.080017] [] dev_hard_start_xmit+0x22f/0x690 > [ 182.080017] [] sch_direct_xmit+0xa1/0x220 > [ 182.080017] [] dev_queue_xmit+0x175/0x770 > [ 182.080017] [] irlap_queue_xmit+0x9a/0xe0 [irda] [...] > [ 182.080017] [] irlmp_discovery_timer_expired+0x23/0x60 [irda] > [ 182.080017] [] call_timer_fn+0x6d/0x2e0 > [ 182.080017] [] run_timer_softirq+0xea/0x260 > [ 182.080017] [] __do_softirq+0x9f/0x360 [...] > [ 182.080017] -> #0 (&(&dev->tx_lock)->rlock){..-...}: > [ 182.080017] [] check_prev_add+0x605/0x610 > [ 182.080017] [] check_prevs_add+0xcb/0x120 > [ 182.080017] [] validate_chain.isra.34+0x557/0x6d0 > [ 182.080017] [] __lock_acquire+0x355/0x820 > [ 182.080017] [] lock_acquire+0x87/0x1b0 > [ 182.080017] [] _raw_spin_lock_irqsave+0x5e/0xa0 > [ 182.080017] [] sirdev_write_complete+0x23/0x280 [sir_dev] > [ 182.080017] [] irtty_write_wakeup+0x31/0x90 [irtty_sir] > [ 182.080017] [] tty_wakeup+0x62/0x70 > [ 182.080017] [] uart_write_wakeup+0x16/0x20 > [ 182.080017] [] serial8250_tx_chars+0x8e/0x110 > [ 182.080017] [] serial8250_handle_irq+0x97/0xa0 > [ 182.080017] [] serial8250_default_handle_irq+0x1c/0x20 > [ 182.080017] [] serial8250_interrupt+0x65/0xd0 > [ 182.080017] [] irq_forced_thread_fn+0x26/0x50 > [ 182.080017] [] irq_thread+0x152/0x1e0 > [ 182.080017] [] kthread+0x72/0x80 > [ 182.080017] [] kernel_thread_helper+0x6/0x10 [...] > [ 182.080017] Possible unsafe locking scenario: > [ 182.080017] > [ 182.080017] CPU0 CPU1 > [ 182.080017] ---- ---- > [ 182.080017] lock(&port_lock_key); > [ 182.080017] lock(&(&dev->tx_lock)->rlock); > [ 182.080017] lock(&port_lock_key); > [ 182.080017] lock(&(&dev->tx_lock)->rlock); > [ 182.080017] > [ 182.080017] *** DEADLOCK *** Once this tx_lock vs port_lock_key deadlock is fixed, there should be a recursive port_lock_key deadlock through sirdev_write_complete own dev->drv->do_write. Paul, Alan, any hindsight about what the sirdev layer should do (or avoid) regarding the latter ? -- Ueimor