From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 479C91A0BCF for ; Fri, 13 Feb 2015 16:27:29 +1100 (AEDT) Received: from e39.co.us.ibm.com (e39.co.us.ibm.com [32.97.110.160]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 89D601401DC for ; Fri, 13 Feb 2015 16:27:27 +1100 (AEDT) Received: from /spool/local by e39.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 12 Feb 2015 22:27:24 -0700 Received: from b01cxnp22035.gho.pok.ibm.com (b01cxnp22035.gho.pok.ibm.com [9.57.198.25]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id 7C74F38C803B for ; Fri, 13 Feb 2015 00:27:22 -0500 (EST) Received: from d01av03.pok.ibm.com (d01av03.pok.ibm.com [9.56.224.217]) by b01cxnp22035.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t1D5RMPn23330872 for ; Fri, 13 Feb 2015 05:27:22 GMT Received: from d01av03.pok.ibm.com (localhost [127.0.0.1]) by d01av03.pok.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t1D5RLa4022172 for ; Fri, 13 Feb 2015 00:27:22 -0500 Message-ID: <54DD8B37.2040903@linux.vnet.ibm.com> Date: Fri, 13 Feb 2015 10:57:19 +0530 From: Preeti U Murthy MIME-Version: 1.0 To: Sam Bobroff , Linux PPC dev , "mpe >> Michael Ellerman" Subject: Re: suspicious RCU usage clockevents_lock, tick_broadcast_lock, hrtimer_bases.lock References: <54DD4BF6.1070503@au1.ibm.com> In-Reply-To: <54DD4BF6.1070503@au1.ibm.com> Content-Type: text/plain; charset=UTF-8 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 02/13/2015 06:27 AM, Sam Bobroff wrote: > Hello, > > I'm receiving this while booting a vanilla 3.19 kernel on a Power 8 machine: Does the below patch fix the issue ? From: Preeti U Murthy [PATCH] tick/hrtimer-broadcast: Fix a suspicious RCU usage in the tick broadcast path --- kernel/time/tick-broadcast-hrtimer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/time/tick-broadcast-hrtimer.c b/kernel/time/tick-broadcast-hrtimer.c index eb682d5..57b8e32 100644 --- a/kernel/time/tick-broadcast-hrtimer.c +++ b/kernel/time/tick-broadcast-hrtimer.c @@ -62,7 +62,7 @@ static int bc_set_next(ktime_t expires, struct clock_event_device *bc) * HRTIMER_RESTART. */ if (hrtimer_try_to_cancel(&bctimer) >= 0) { - hrtimer_start(&bctimer, expires, HRTIMER_MODE_ABS_PINNED); + RCU_NONIDLE(hrtimer_start(&bctimer, expires, HRTIMER_MODE_ABS_PINNED)); /* Bind the "device" to the cpu */ bc->bound_on = smp_processor_id(); } else if (bc->bound_on == smp_processor_id()) { -- Regards Preeti U Murthy > > [ 2.522179] device-mapper: uevent: version 1.0.3 > [ 2.522741] device-mapper: ioctl: 4.29.0-ioctl (2014-10-28) > initialised: dm-devel@redhat.com > [ 2.543590] > [ 2.543630] =============================== > [ 2.543709] [ INFO: suspicious RCU usage. ] > [ 2.543758] 3.19.0samb #2 Not tainted > [ 2.543802] ------------------------------- > [ 2.543847] include/trace/events/timer.h:186 suspicious > rcu_dereference_check() usage! > [ 2.543940] > [ 2.543940] other info that might help us debug this: > [ 2.543940] > [ 2.544035] > [ 2.544035] RCU used illegally from idle CPU! > [ 2.544035] rcu_scheduler_active = 1, debug_locks = 0 > [ 2.544154] RCU used illegally from extended quiescent state! > [ 2.544234] 3 locks held by swapper/1/0: > [ 2.544284] #0: (clockevents_lock){-.....}, at: > [] .clockevents_notify+0x5c/0x320 > [ 2.544464] #1: (tick_broadcast_lock){-.-...}, at: > [] .tick_broadcast_oneshot_control+0xe4/0x530 > [ 2.544654] #2: (hrtimer_bases.lock#2){-.-...}, at: > [] .__hrtimer_start_range_ns+0x124/0x6e0 > [ 2.544843] > [ 2.544843] stack backtrace: > [ 2.544904] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.19.0samb #2 > [ 2.544986] Call Trace: > [ 2.545023] [c000000fdf6f7770] [c000000000faf118] > .dump_stack+0x98/0xd4 (unreliable) > [ 2.545124] [c000000fdf6f77f0] [c000000000152b78] > .lockdep_rcu_suspicious+0x138/0x180 > [ 2.545225] [c000000fdf6f7880] [c000000000191374] > .enqueue_hrtimer+0x1c4/0x300 > [ 2.545325] [c000000fdf6f7910] [c00000000019276c] > .__hrtimer_start_range_ns+0x1fc/0x6e0 > [ 2.545425] [c000000fdf6f7a10] [c0000000001a8e90] .bc_set_next+0xc0/0xf0 > [ 2.545510] [c000000fdf6f7aa0] [c0000000001a51f0] > .clockevents_program_event+0x100/0x1f0 > [ 2.545607] [c000000fdf6f7b40] [c0000000001a6bac] > .tick_broadcast_set_event+0x6c/0x120 > [ 2.545705] [c000000fdf6f7bd0] [c0000000001a7c94] > .tick_broadcast_oneshot_control+0x2b4/0x530 > [ 2.545802] [c000000fdf6f7ca0] [c0000000001a4818] > .clockevents_notify+0x2a8/0x320 > [ 2.545898] [c000000fdf6f7d70] [c0000000001484f4] > .cpu_startup_entry+0x404/0x730 > [ 2.545995] [c000000fdf6f7ec0] [c000000000044314] > .start_secondary+0x3a4/0x460 > [ 2.546092] [c000000fdf6f7f90] [c000000000008bfc] > start_secondary_prolog+0x10/0x14 > [ 2.546555] Registering IBM Power 842 compression driver > > Cheers, > Sam. > > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/linuxppc-dev >