From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755352AbeDWNkz (ORCPT ); Mon, 23 Apr 2018 09:40:55 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:56898 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754881AbeDWNkv (ORCPT ); Mon, 23 Apr 2018 09:40:51 -0400 Date: Mon, 23 Apr 2018 15:40:45 +0200 (CEST) From: Sebastian Ott X-X-Sender: sebott@schleppi To: "Theodore Ts'o" cc: linux-kernel@vger.kernel.org Subject: [BUG, PATCH] random: sleep in irq context User-Agent: Alpine 2.21 (LFD 202 2017-01-01) Organization: =?ISO-8859-15?Q?=22IBM_Deutschland_Research_&_Development_GmbH?= =?ISO-8859-15?Q?_=2F_Vorsitzende_des_Aufsichtsrats=3A_Martina?= =?ISO-8859-15?Q?_Koederitz_Gesch=E4ftsf=FChrung=3A_Dirk_Wittkopp?= =?ISO-8859-15?Q?_Sitz_der_Gesellschaft=3A_B=F6blingen_=2F_Reg?= =?ISO-8859-15?Q?istergericht=3A_Amtsgericht_Stuttgart=2C_HRB_2432?= =?ISO-8859-15?Q?94=22?= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-TM-AS-GCONF: 00 x-cbid: 18042313-0040-0000-0000-00000431FDCA X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18042313-0041-0000-0000-00002636245D Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-23_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=3 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1804230139 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Today I observed the following lockdep splat: irq event stamp: 36 ================================ hardirqs last enabled at (35): [<00000000008e6bc6>] _raw_spin_unlock_irqrestore+0x7e/0xb0 hardirqs last disabled at (36): [<00000000008e6884>] _raw_spin_lock_irqsave+0x3c/0xb8 softirqs last enabled at (0): [<00000000001431da>] copy_process.part.8+0x42a/0x1e10 softirqs last disabled at (0): [<0000000000000000>] (null) WARNING: inconsistent lock state 4.17.0-rc2-00001-gc50517a06b5f #186 Not tainted -------------------------------- inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage. swapper/4/0 [HC1[1]:SC0[0]:HE0:SE1] takes: (ptrval) (fs_reclaim){?.+.}, at: fs_reclaim_acquire.part.13+0x0/0x60 {HARDIRQ-ON-W} state was registered at: __lock_acquire+0x3da/0x13f0 lock_acquire+0xf6/0x290 fs_reclaim_acquire.part.13+0x52/0x60 kmem_cache_alloc_node_trace+0x52/0x408 alloc_worker+0x3e/0x88 init_rescuer.part.7+0x32/0xc8 workqueue_init+0x26a/0x388 kernel_init_freeable+0x11a/0x5a0 kernel_init+0x2a/0x158 kernel_thread_starter+0x6/0xc kernel_thread_starter+0x0/0xc irq event stamp: 1780 hardirqs last enabled at (1777): [<000000000010386a>] enabled_wait+0x52/0x138 hardirqs last disabled at (1778): [<00000000008e8336>] ext_int_handler+0x122/0x140 softirqs last enabled at (1780): [<000000000014f424>] irq_enter+0x8c/0x98 softirqs last disabled at (1779): [<000000000014f408>] irq_enter+0x70/0x98 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(fs_reclaim); lock(fs_reclaim); *** DEADLOCK *** no locks held by swapper/4/0. stack backtrace: CPU: 4 PID: 0 Comm: swapper/4 Not tainted 4.17.0-rc2-00001-gc50517a06b5f #186 Hardware name: IBM 3906 M04 704 (LPAR) Call Trace: ([<0000000000114bbc>] show_stack+0x9c/0x108) [<00000000008c52ca>] dump_stack+0x9a/0xd8 [<00000000001b9a64>] print_usage_bug+0x25c/0x300 [<00000000001ba1aa>] mark_lock+0x6a2/0x6f8 [<00000000001bb49c>] __lock_acquire+0xc64/0x13f0 [<00000000001bc49e>] lock_acquire+0xf6/0x290 [<00000000002edc82>] fs_reclaim_acquire.part.13+0x52/0x60 [<0000000000375e42>] __kmalloc+0x62/0x438 [<00000000006283b2>] crng_reseed+0x142/0x368 [<0000000000628998>] credit_entropy_bits+0x3c0/0x3f8 [<000000000062959c>] add_interrupt_randomness+0x204/0x298 [<00000000001d44a4>] handle_irq_event_percpu+0x54/0x88 [<00000000001d8e54>] handle_percpu_irq+0x84/0xb0 [<00000000001d2ffa>] generic_handle_irq+0x42/0x60 [<000000000010d3c4>] do_IRQ+0xa4/0xf0 [<00000000008e8350>] ext_int_handler+0x13c/0x140 [<0000000000103882>] enabled_wait+0x6a/0x138 ([<000000000010386a>] enabled_wait+0x52/0x138) [<0000000000103d4a>] arch_cpu_idle+0x32/0x50 [<00000000008e659e>] default_idle_call+0x3e/0x68 [<00000000001889aa>] do_idle+0xea/0x1c0 [<0000000000188d26>] cpu_startup_entry+0x3e/0x48 [<000000000011758e>] smp_start_secondary+0x13e/0x158 [<00000000008e87a2>] restart_int_handler+0x5a/0x70 [<0000000000000000>] (null) INFO: lockdep is turned off. BUG: sleeping function called from invalid context at mm/slab.h:421 in_atomic(): 1, irqs_disabled(): 1, pid: 0, name: swapper/4 INFO: lockdep is turned off. irq event stamp: 1780 hardirqs last enabled at (1777): [<000000000010386a>] enabled_wait+0x52/0x138 hardirqs last disabled at (1778): [<00000000008e8336>] ext_int_handler+0x122/0x140 softirqs last enabled at (1780): [<000000000014f424>] irq_enter+0x8c/0x98 softirqs last disabled at (1779): [<000000000014f408>] irq_enter+0x70/0x98 Preemption disabled at: [<00000000001174f6>] smp_start_secondary+0xa6/0x158 CPU: 4 PID: 0 Comm: swapper/4 Not tainted 4.17.0-rc2-00001-gc50517a06b5f #186 Hardware name: IBM 3906 M04 704 (LPAR) Call Trace: ([<0000000000114bbc>] show_stack+0x9c/0x108) [<00000000008c52ca>] dump_stack+0x9a/0xd8 [<000000000017d256>] ___might_sleep+0x216/0x278 [<000000000037607c>] __kmalloc+0x29c/0x438 [<00000000006283b2>] crng_reseed+0x142/0x368 [<0000000000628998>] credit_entropy_bits+0x3c0/0x3f8 [<000000000062959c>] add_interrupt_randomness+0x204/0x298 [<00000000001d44a4>] handle_irq_event_percpu+0x54/0x88 [<00000000001d8e54>] handle_percpu_irq+0x84/0xb0 [<00000000001d2ffa>] generic_handle_irq+0x42/0x60 [<000000000010d3c4>] do_IRQ+0xa4/0xf0 [<00000000008e8350>] ext_int_handler+0x13c/0x140 [<0000000000103882>] enabled_wait+0x6a/0x138 ([<000000000010386a>] enabled_wait+0x52/0x138) [<0000000000103d4a>] arch_cpu_idle+0x32/0x50 [<00000000008e659e>] default_idle_call+0x3e/0x68 [<00000000001889aa>] do_idle+0xea/0x1c0 [<0000000000188d26>] cpu_startup_entry+0x3e/0x48 [<000000000011758e>] smp_start_secondary+0x13e/0x158 [<00000000008e87a2>] restart_int_handler+0x5a/0x70 [<0000000000000000>] (null) INFO: lockdep is turned off. This happend once during boot and I could not reproduce this since, but I think the following patch should fix the issue: ----->8 >>From 9d29e0c92efaf94277bc178782523283958ae8c8 Mon Sep 17 00:00:00 2001 From: Sebastian Ott Date: Mon, 23 Apr 2018 14:59:20 +0200 Subject: [PATCH] random: don't sleep during allocations in irq context Since numa_crng_init() can be called from irq context let's use __GFP_ATOMIC for allocations. Fixes: 8ef35c866f88 ("random: set up the NUMA crng instances...") Signed-off-by: Sebastian Ott --- drivers/char/random.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index 3cd3aae24d6d..e96ea2bf7241 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -791,14 +791,14 @@ static void crng_initialize(struct crng_state *crng) #ifdef CONFIG_NUMA static void numa_crng_init(void) { + gfp_t gfp_flags = GFP_KERNEL | __GFP_NOFAIL | __GFP_ATOMIC; int i; struct crng_state *crng; struct crng_state **pool; - pool = kcalloc(nr_node_ids, sizeof(*pool), GFP_KERNEL|__GFP_NOFAIL); + pool = kcalloc(nr_node_ids, sizeof(*pool), gfp_flags); for_each_online_node(i) { - crng = kmalloc_node(sizeof(struct crng_state), - GFP_KERNEL | __GFP_NOFAIL, i); + crng = kmalloc_node(sizeof(struct crng_state), gfp_flags, i); spin_lock_init(&crng->lock); crng_initialize(crng); pool[i] = crng; -- 2.13.4