From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 58941C433F5 for ; Mon, 7 Mar 2022 11:08:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239805AbiCGLJp (ORCPT ); Mon, 7 Mar 2022 06:09:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50520 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241518AbiCGLJK (ORCPT ); Mon, 7 Mar 2022 06:09:10 -0500 Received: from mail-wr1-x42b.google.com (mail-wr1-x42b.google.com [IPv6:2a00:1450:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 25C9973065; Mon, 7 Mar 2022 02:31:24 -0800 (PST) Received: by mail-wr1-x42b.google.com with SMTP id j26so12075963wrb.1; Mon, 07 Mar 2022 02:31:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:to:cc:subject:message-id:mime-version:content-disposition; bh=xLnzYDLYheb8EHYEyiymkaq0+GyHWExGgRc6Etv2XG8=; b=o9+mroNCBA0Rvqc6hYCtXIqQasJ5Nkdg28o4D7F5f5hVwjgUIsaZO/gmrvami1roSg b0chE+GdzTyhNYASmzWIQzTOU+w81umIsYQV0p5GG3vLFPwQcCUydfX+NwBmyRORzKp3 veIlesAOqvAxPvfRge8BBGCj1uVe3thjdIKCwy4ALc4jLSRfSCQs6rgmaSWdYIn4h7ow 3gmyJLK+ssbADfwrC/DZEct7o+an0b1A3aov4tqul3UgY59syzvsmhkE+9PvAyPAepcc kcjhnWXUSD+cdfqmWuQIiNMkgJ6doFaJFtn5oqibZs5CGbX4Gfc95/LN/nA69Qd/lryy 8kbA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition; bh=xLnzYDLYheb8EHYEyiymkaq0+GyHWExGgRc6Etv2XG8=; b=1OyjdOAtpirxD9yEz6fgDKp279JfEXxyW7bolmbas4b9MHjWHV8d/a6liK2s44WobQ KJzUBqevkndvNekn+I6FW7sSP5xiBxGm7tbYReQ1h0MzE3UDT2k/Qy5eYTycIuioFrmy 62zW1di8hQdh2T8aPFCEc96oi8jzoJi0p6HNek0+FyPWJ6yufjut06D+Rly8fM0aMdXF mQAiqBnBhHl+Pu9qJyK0CZ74yWwjpJD58Uc8SDz7Tis+SuT5E9QR1fsMRxe+keCIpSZg l++wfNkRUFFk5gPpTwIlkCcw98elEYVi1X/0jDaf/anDMfOZNDzPWKjSkXZdUrXix4ek 0jxg== X-Gm-Message-State: AOAM533RvbNqv9AnlSiI1HyFazNBE12XZ2mhUrlQXaH50B1lRXhQH7g/ wTtjXiXSrSBNYqFU/xkhrUU= X-Google-Smtp-Source: ABdhPJz6T8addN0Kbj7Lj+UNgFNrXQ02akA2rxzM9XUK/xrFY6JJ8IY+O9i00Vlh1LDDQCSQawC8eA== X-Received: by 2002:a5d:490f:0:b0:1f0:6791:a215 with SMTP id x15-20020a5d490f000000b001f06791a215mr7854253wrq.422.1646649082573; Mon, 07 Mar 2022 02:31:22 -0800 (PST) Received: from Red ([2a01:cb1d:3d5:a100:264b:feff:fe03:2806]) by smtp.googlemail.com with ESMTPSA id bj7-20020a0560001e0700b001f1d7822865sm6727591wrb.43.2022.03.07.02.31.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Mar 2022 02:31:22 -0800 (PST) Date: Mon, 7 Mar 2022 11:31:20 +0100 From: Corentin Labbe To: tj@kernel.org, lizefan.x@bytedance.com, hannes@cmpxchg.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, zhouchengming@bytedance.com Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org Subject: WARNING: suspicious RCU usage since next-20220304 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Booting my sun8i-a83t-bananapi-m3 since next-20220304 lead to lot of RCU warning: [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache [ 0.000000] OF: fdt: Machine model: Banana Pi BPI-M3 [ 0.000000] earlycon: uart0 at MMIO32 0x01c28000 (options '') [ 0.000000] printk: bootconsole [uart0] enabled [ 0.000000] Memory policy: Data cache writealloc [ 0.000000] cma: Reserved 16 MiB at 0xbf000000 [ 0.000000] Zone ranges: [ 0.000000] Normal [mem 0x0000000040000000-0x000000006fffffff] [ 0.000000] HighMem [mem 0x0000000070000000-0x00000000bfffffff] [ 0.000000] Movable zone start for each node [ 0.000000] Early memory node ranges [ 0.000000] node 0: [mem 0x0000000040000000-0x00000000bfffffff] [ 0.000000] Initmem setup node 0 [mem 0x0000000040000000-0x00000000bfffffff] [ 0.000000] percpu: Embedded 16 pages/cpu s34740 r8192 d22604 u65536 [ 0.000000] Built 1 zonelists, mobility grouping on. Total pages: 522752 [ 0.000000] Kernel command line: console=ttyS0,115200n8 root=/dev/ram0 earlycon=uart,mmio32,0x01c28000 ip=dhcp [ 0.000000] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes, linear) [ 0.000000] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes, linear) [ 0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off [ 0.000000] Memory: 2017876K/2097152K available (8192K kernel code, 1395K rwdata, 2956K rodata, 1024K init, 7184K bss, 62892K reserved, 16384K cma-reserved, 1294336K highmem) [ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=8, Nodes=1 [ 0.000000] trace event string verifier disabled [ 0.000000] Running RCU self tests [ 0.000000] rcu: Hierarchical RCU implementation. [ 0.000000] rcu: RCU event tracing is enabled. [ 0.000000] rcu: RCU lockdep checking is enabled. [ 0.000000] rcu: RCU calculated value of scheduler-enlistment delay is 10 jiffies. [ 0.000000] NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16 [ 0.000000] rcu: srcu_init: Setting srcu_struct sizes based on contention. [ 0.000000] random: get_random_bytes called from start_kernel+0x534/0x6cc with crng_init=0 [ 0.000000] arch_timer: cp15 timer(s) running at 24.00MHz (virt). [ 0.000000] clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0x588fe9dc0, max_idle_ns: 440795202592 ns [ 0.000003] sched_clock: 56 bits at 24MHz, resolution 41ns, wraps every 4398046511097ns [ 0.008649] Switching to timer-based delay loop, resolution 41ns [ 0.015608] clocksource: timer: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 79635851949 ns [ 0.026505] Console: colour dummy device 80x30 [ 0.031367] Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar [ 0.039759] ... MAX_LOCKDEP_SUBCLASSES: 8 [ 0.044185] ... MAX_LOCK_DEPTH: 48 [ 0.048693] ... MAX_LOCKDEP_KEYS: 8192 [ 0.053417] ... CLASSHASH_SIZE: 4096 [ 0.058117] ... MAX_LOCKDEP_ENTRIES: 32768 [ 0.062911] ... MAX_LOCKDEP_CHAINS: 65536 [ 0.067721] ... CHAINHASH_SIZE: 32768 [ 0.072516] memory used by lock dependency info: 4061 kB [ 0.078364] memory used for stack traces: 2112 kB [ 0.083533] per task-struct memory footprint: 1536 bytes [ 0.089482] Calibrating delay loop (skipped), value calculated using timer frequency.. 48.00 BogoMIPS (lpj=240000) [ 0.100709] pid_max: default: 32768 minimum: 301 [ 0.106465] Mount-cache hash table entries: 2048 (order: 1, 8192 bytes, linear) [ 0.114435] Mountpoint-cache hash table entries: 2048 (order: 1, 8192 bytes, linear) [ 0.125719] CPU: Testing write buffer coherency: ok [ 0.132334] [ 0.134009] ============================= [ 0.138348] WARNING: suspicious RCU usage [ 0.142679] 5.17.0-rc6-next-20220307-00130-g074e6e0284df-dirty #222 Not tainted [ 0.150565] ----------------------------- [ 0.154901] include/linux/cgroup.h:481 suspicious rcu_dereference_check() usage! [ 0.162883] [ 0.162883] other info that might help us debug this: [ 0.162883] [ 0.171509] [ 0.171509] rcu_scheduler_active = 1, debug_locks = 1 [ 0.178546] 2 locks held by kthreadd/2: [ 0.182694] #0: c19216b4 (&p->pi_lock){....}-{2:2}, at: task_rq_lock+0x34/0x134 [ 0.190763] #1: eef68b50 (&rq->__lock){-...}-{2:2}, at: task_rq_lock+0x5c/0x134 [ 0.198810] [ 0.198810] stack backtrace: [ 0.203522] CPU: 0 PID: 2 Comm: kthreadd Not tainted 5.17.0-rc6-next-20220307-00130-g074e6e0284df-dirty #222 [ 0.214132] Hardware name: Allwinner A83t board [ 0.219031] unwind_backtrace from show_stack+0x10/0x14 [ 0.224690] show_stack from 0xf0835e8c [ 0.228933] [ 0.230564] ============================= [ 0.234891] WARNING: suspicious RCU usage [ 0.239217] 5.17.0-rc6-next-20220307-00130-g074e6e0284df-dirty #222 Not tainted [ 0.247108] ----------------------------- [ 0.251433] include/linux/cgroup.h:481 suspicious rcu_dereference_check() usage! [ 0.259419] [ 0.259419] other info that might help us debug this: [ 0.259419] [ 0.268061] [ 0.268061] rcu_scheduler_active = 1, debug_locks = 1 [ 0.275103] no locks held by kthreadd/2. [ 0.279336] [ 0.279336] stack backtrace: [ 0.284043] CPU: 0 PID: 2 Comm: kthreadd Not tainted 5.17.0-rc6-next-20220307-00130-g074e6e0284df-dirty #222 [ 0.294643] Hardware name: Allwinner A83t board [ 0.299534] unwind_backtrace from show_stack+0x10/0x14 [ 0.305193] show_stack from 0xf0801efc [ 0.309508] /cpus/cpu@0 missing clock-frequency property [ 0.315324] /cpus/cpu@1 missing clock-frequency property [ 0.321178] /cpus/cpu@2 missing clock-frequency property [ 0.326983] /cpus/cpu@3 missing clock-frequency property [ 0.332833] /cpus/cpu@100 missing clock-frequency property [ 0.338835] /cpus/cpu@101 missing clock-frequency property [ 0.344897] /cpus/cpu@102 missing clock-frequency property [ 0.350930] /cpus/cpu@103 missing clock-frequency property [ 0.356920] CPU0: thread -1, cpu 0, socket 0, mpidr 80000000 [ 0.366264] Setting up static identity map for 0x40100000 - 0x40100060 [ 0.374286] ARM CCI driver probed [ 0.378726] sunxi multi cluster SMP support installed [ 0.385497] rcu: Hierarchical SRCU implementation. [ 0.391811] [ 0.393463] ============================= [ 0.397800] WARNING: suspicious RCU usage [ 0.402138] 5.17.0-rc6-next-20220307-00130-g074e6e0284df-dirty #222 Not tainted [ 0.410033] ----------------------------- [ 0.414358] include/linux/cgroup.h:481 suspicious rcu_dereference_check() usage! [ 0.422337] [ 0.422337] other info that might help us debug this: [ 0.422337] [ 0.430972] [ 0.430972] rcu_scheduler_active = 1, debug_locks = 1 [ 0.438016] 1 lock held by migration/0/12: [ 0.442441] #0: eef68b50 (&rq->__lock){-...}-{2:2}, at: __schedule+0xf4/0xaa4 [ 0.450325] [ 0.450325] stack backtrace: [ 0.455037] CPU: 0 PID: 12 Comm: migration/0 Not tainted 5.17.0-rc6-next-20220307-00130-g074e6e0284df-dirty #222 [ 0.466027] Hardware name: Allwinner A83t board [ 0.470920] Stopper: 0x0 <- 0x0 [ 0.474328] unwind_backtrace from show_stack+0x10/0x14 [ 0.479980] show_stack from 0xf087debc I bisect it to dc6e0818bc9a0336d9accf3ea35d146d72aa7a18 sched/cpuacct: Optimize away RCU read lock reverting this commit removed some RCU but the boot is clean since I reverted also 3eba0505d03a9c1eb30d40c2330c0880b22d1b3a "sched/cpuacct: Remove redundant RCU read lock" Regards