Message-ID: <20091208153557.GD6799@linux.vnet.ibm.com>
Date:	Tue, 8 Dec 2009 07:35:58 -0800
From:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:	kordex - <kordex@...il.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: Badness at kernel/rcutree.c:1228

On Tue, Dec 08, 2009 at 01:54:38PM +0200, kordex - wrote:
> Hey,
> 
> I did add the printk and warn_once lines you requested and the output
> from them is:
> 
> Hierarchical RCU implementation.
> rcu_init() smp_processor_id() = 0
> rcu_init_percpu_data(0) called
> rcu_init_percpu_data(0) called

So both rcu_sched_state.beenonline and rcu_bh_state.beenonline have
been set to 1 by the line immediately preceding the one that printed
out "rcu_init_percpu_data(0) called".  This is the only line that
assigns a value to the beenonline field.

My suggestion is to bisect the portion of the boot process immediately
preceding the WARN_ON_ONCE() from the prior boot to locate whatever
is clobbering that value.

							Thanx, Paul

> Full dmesg at http://xnet.fi/opt/apps/lkml-2.6.32-vanilla.dmesg.printk.txt
> 
> Captured just right after boot so it does not yet have anything else
> than just clean boot messages.
> 
> --Mikko Kortelainen
> 
> 2009/12/8 Paul E. McKenney <paulmck@...ux.vnet.ibm.com>:
> > On Mon, Dec 07, 2009 at 08:58:35PM +0200, kordex - wrote:
> >> Hello,
> >>
> >> I encountered this and I am able to reproduce, unfortunately. I was
> >> syncing files from two large HDD drives and I saw difference between
> >> cksum so I first suspected faulty filesystem but it was not that. Then
> >> I ran couple of Seagate Seatools tests on these disks of mine, still
> >> nothing. I suspected there was something bad in rsync(1) code but
> >> still negative as tar worked in the same way. Ofcourse I did the dmesg
> >> checking but after reboot after checking the disks were fine.  It
> >> showed up clean. So I went there and tried to resync my non raid disk
> >> with raid0 disk. Still same problem, data mismatch. I read something
> >> from google when installing new sata controller about lib_sata an sil
> >> 3114 and seagates disks not working so this time i though of checking
> >> dmesg. And there it was nice little surprise:
> >>
> >> ------------[ cut here ]------------
> >> Badness at kernel/rcutree.c:1228
> >> NIP: c004ecbc LR: c004f14c CTR: c007bd70
> >> REGS: df34dde0 TRAP: 0700   Not tainted  (2.6.32)
> >> MSR: 00029032 <EE,ME,CE,IR,DR>  CR: 24024482  XER: 20000000
> >> TASK = d12c2d10[2734] 'buffer' THREAD: df34c000
> >> GPR00: 00000001 df34de90 d12c2d10 c0746498 c07465a0 00b1ed55 00000001 00138c4a
> >> GPR08: 00001032 c07b0000 00009032 00000008 44024488 1001c6ac 1002efd8 1002f064
> >> GPR16: 10060000 10070000 10070000 c073a590 c073a710 c0685204 00000000 c07a5520
> >> GPR24: c07a5520 0000000a df34c000 c0746498 c0746420 c0746528 00000009 c07465a0
> >> NIP [c004ecbc] __rcu_process_callbacks+0x34/0x48c
> >> LR [c004f14c] rcu_process_callbacks+0x38/0x4c
> >> Call Trace:
> >> [df34de90] [c004efec] __rcu_process_callbacks+0x364/0x48c (unreliable)
> >> [df34deb0] [c004f14c] rcu_process_callbacks+0x38/0x4c
> >> [df34ded0] [c0028e8c] __do_softirq+0xa4/0x120
> >> [df34df10] [c0006a0c] do_softirq+0x40/0x58
> >> [df34df20] [c0028c8c] irq_exit+0x38/0x80
> >> [df34df30] [c0010d28] timer_interrupt+0x11c/0x138
> >> [df34df40] [c00143a0] ret_from_except+0x0/0x14
> >> --- Exception: 901 at 0x10002ddc
> >>     LR = 0x10002d80
> >> Instruction dump:
> >> 7c0802a6 bf410008 7c9f2378 7c7b1b78 90010024 8804000e 2f800000 40be002c
> >> 3d20c07b 8009a334 7c000034 5400d97e <0f000000> 2f800000 41be0010 38000001
> >> munin-update: page allocation failure. order:1, mode:0x20
> >> Call Trace:
> >> [c59bfa30] [c0008a24] show_stack+0x4c/0x14c (unreliable)
> >> [c59bfa70] [c0058154] __alloc_pages_nodemask+0x468/0x4b8
> >> [c59bfb00] [c0077448] cache_alloc_refill+0x2d8/0x55c
> >> [c59bfb50] [c0077830] kmem_cache_alloc+0x64/0xb0
> >> [c59bfb70] [c04862fc] sk_prot_alloc+0x2c/0x78
> >> [c59bfb90] [c04863e0] sk_clone+0x20/0x1b0
> >> [c59bfbb0] [c04bca70] inet_csk_clone+0x1c/0x8c
> >> [c59bfbc0] [c04d1358] tcp_create_openreq_child+0x20/0x2c4
> >> [c59bfbe0] [c04d00a0] tcp_v4_syn_recv_sock+0x58/0x17c
> >> [c59bfc00] [c04d11c4] tcp_check_req+0x268/0x3dc
> >> [c59bfc40] [c04cf87c] tcp_v4_do_rcv+0xa0/0x198
> >> [c59bfc70] [c04cfdb8] tcp_v4_rcv+0x444/0x6d4
> >> [c59bfca0] [c04b450c] ip_local_deliver+0x104/0x1d8
> >> [c59bfcc0] [c04b43d0] ip_rcv+0x508/0x540
> >> [c59bfcf0] [c049227c] netif_receive_skb+0x390/0x3bc
> >> [c59bfd20] [c0492344] process_backlog+0x9c/0x134
> >> [c59bfd50] [c0492b44] net_rx_action+0x80/0x190
> >> [c59bfd80] [c0028e8c] __do_softirq+0xa4/0x120
> >> [c59bfdc0] [c0006a0c] do_softirq+0x40/0x58
> >> [c59bfdd0] [c0028db4] local_bh_enable+0x7c/0x9c
> >> [c59bfde0] [c04852c8] release_sock+0x94/0xa8
> >> [c59bfe00] [c04dcd48] inet_stream_connect+0x224/0x29c
> >> [c59bfe50] [c0482a54] sys_connect+0x78/0xa8
> >> [c59bff00] [c0484088] sys_socketcall+0xf0/0x240
> >> [c59bff40] [c0013cf4] ret_from_syscall+0x0/0x38
> >> --- Exception: c01 at 0xfd51434
> >>     LR = 0xff66550
> >> Mem-Info:
> >> DMA per-cpu:
> >> CPU    0: hi:  186, btch:  31 usd:  87
> >> active_anon:6308 inactive_anon:8347 isolated_anon:0
> >>  active_file:52970 inactive_file:53351 isolated_file:0
> >>  unevictable:0 dirty:12753 writeback:0 unstable:0
> >>  free:1728 slab_reclaimable:2017 slab_unreclaimable:1020
> >>  mapped:2045 shmem:410 pagetables:431 bounce:0
> >> DMA free:6912kB min:2884kB low:3604kB high:4324kB active_anon:25232kB
> >> inactive_anon:33388kB active_file:211880kB inactive_file:213404kB
> >> unevictable:0kB isolated(anon):0kB isolated(file):0kB present:520192kB
> >> mlocked:0kB dirty:51012kB writeback:0kB mapped:8180kB shmem:1640kB
> >> slab_reclaimable:8068kB slab_unreclaimable:4080kB kernel_stack:992kB
> >> pagetables:1724kB unstable:0kB bounce:0kB writeback_tmp:0kB
> >> pages_scanned:0 all_unreclaimable? no
> >> lowmem_reserve[]: 0 0 0 0
> >> DMA: 1728*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB
> >> 0*1024kB 0*2048kB 0*4096kB = 6912kB
> >> 106743 total pagecache pages
> >> 0 pages in swap cache
> >> Swap cache stats: add 0, delete 0, find 0/0
> >> Free swap  = 779144kB
> >> Total swap = 779144kB
> >> 131072 pages RAM
> >> 0 pages HighMem
> >> 3391 pages reserved
> >> 14583 pages shared
> >> 121040 pages non-shared
> >>
> >> ...
> >>
> >> Full dmesg: http://xnet.fi/opt/apps/lkml-2.6.32-vanilla.dmesg.txt
> >> Kernel config: http://xnet.fi/opt/apps/lkml-2.6.32-vanilla.config.txt
> >
> > Interesting!  You appear to be running a UP build on a 32-bit PowerPC
> > platform, which presumably disables CPU hotplug.  You are also running
> > CONFIG_TREE_RCU, which does require initialization.  Your dmesg snippet
> > seems to start after RCU initialized itself, as it would normally print:
> >
> >        Hierarchical RCU implementation.
> >
> > Are you able to capture console output that early?  If so, could you
> > please try the attached patch?
> >
> > The behavior is consistent with the boot CPU thinking that it is not
> > online, which would indeed be strange.  The patch checks on this and
> > also prints out at the point that ->beenonline should be initialized.
> >
> >> uname -a: Linux navi 2.6.32 #2 Mon Dec 7 13:35:57 EET 2009 ppc GNU/Linux
> >>
> >> And no I am not running any patches on this. Same occurred with
> >> 2.6.31.6 which I had patched with Con Kolivas' BFS so I upgraded to
> >> latest stable vanilla without any patches and still there it is. You
> >> know, it ain't too interesting to sync 1TB disks 5 times (yea I needed
> >> to do some testing for rsync) with slow controllers like these.
> >
> > You also have quite a few occurrences of the following splat in your
> > dmesg, which might well explain your sync-ing woes:
> >
> >        Mem-Info:
> >        DMA per-cpu:
> >        CPU    0: hi:  186, btch:  31 usd: 153
> >        active_anon:8938 inactive_anon:9432 isolated_anon:0
> >         active_file:11943 inactive_file:91997 isolated_file:0
> >         unevictable:0 dirty:4317 writeback:3464 unstable:0
> >         free:1044 slab_reclaimable:1160 slab_unreclaimable:1123
> >         mapped:3207 shmem:411 pagetables:471 bounce:0
> >        DMA free:4176kB min:2884kB low:3604kB high:4324kB active_anon:35752kB
> >        inactive_anon:37728kB active_file:47772kB inactive_file:367988kB
> >        unevictable:0kB isolated(anon):0kB isolated(file):0kB present:520192kB
> >        mlocked:0kB dirty:17268kB writeback:13856kB mapped:12828kB shmem:1644kB
> >        slab_reclaimable:4640kB slab_unreclaimable:4492kB kernel_stack:1040kB
> >        pagetables:1884kB unstable:0kB bounce:0kB writeback_tmp:0kB
> >        pages_scanned:0 all_unreclaimable? no
> >        lowmem_reserve[]: 0 0 0 0
> >        DMA: 1034*4kB 5*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB
> >        0*1024kB 0*2048kB 0*4096kB = 4176kB
> >        104353 total pagecache pages
> >        0 pages in swap cache
> >        Swap cache stats: add 0, delete 0, find 0/0
> >        Free swap  = 779144kB
> >        Total swap = 779144kB
> >        131072 pages RAM
> >        0 pages HighMem
> >        3391 pages reserved
> >        14353 pages shared
> >        120982 pages non-shared
> >        mconf: page allocation failure. order:1, mode:0x20
> >        Call Trace:
> >        [d1197cb0] [c0008a24] show_stack+0x4c/0x14c (unreliable)
> >        [d1197cf0] [c0058154] __alloc_pages_nodemask+0x468/0x4b8
> >        [d1197d80] [c0077448] cache_alloc_refill+0x2d8/0x55c
> >        [d1197dd0] [c0077780] __kmalloc+0xb4/0x100
> >        [d1197df0] [c02aa6bc] tty_buffer_request_room+0xcc/0x148
> >        [d1197e10] [c02aa8f4] tty_insert_flip_string+0x2c/0xa0
> >        [d1197e30] [c02ab678] pty_write+0x40/0x70
> >        [d1197e50] [c02a6244] n_tty_write+0x260/0x3bc
> >        [d1197eb0] [c02a3780] tty_write+0x1bc/0x260
> >        [d1197ef0] [c007b4d4] vfs_write+0xb8/0x180
> >        [d1197f10] [c007b67c] sys_write+0x4c/0x8c
> >        [d1197f40] [c0013cf4] ret_from_syscall+0x0/0x38
> >        --- Exception: c01 at 0xfef4034
> >            LR = 0xfe97624
> >        Mem-Info:
> >        DMA per-cpu:
> >        CPU    0: hi:  186, btch:  31 usd: 153
> >        active_anon:8938 inactive_anon:9432 isolated_anon:0
> >         active_file:11943 inactive_file:91997 isolated_file:0
> >         unevictable:0 dirty:4317 writeback:3336 unstable:0
> >         free:1044 slab_reclaimable:1160 slab_unreclaimable:1123
> >         mapped:3207 shmem:411 pagetables:471 bounce:0
> >        DMA free:4176kB min:2884kB low:3604kB high:4324kB active_anon:35752kB
> >        inactive_anon:37728kB active_file:47772kB inactive_file:367988kB
> >        unevictable:0kB isolated(anon):0kB isolated(file):0kB present:520192kB
> >        mlocked:0kB dirty:17268kB writeback:13344kB mapped:12828kB shmem:1644kB
> >        slab_reclaimable:4640kB slab_unreclaimable:4492kB kernel_stack:1040kB
> >        pagetables:1884kB unstable:0kB bounce:0kB writeback_tmp:0kB
> >        pages_scanned:0 all_unreclaimable? no
> >        lowmem_reserve[]: 0 0 0 0
> >        DMA: 1034*4kB 5*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB
> >        0*1024kB 0*2048kB 0*4096kB = 4176kB
> >        104353 total pagecache pages
> >        0 pages in swap cache
> >        Swap cache stats: add 0, delete 0, find 0/0
> >        Free swap  = 779144kB
> >        Total swap = 779144kB
> >        131072 pages RAM
> >        0 pages HighMem
> >        3391 pages reserved
> >        14353 pages shared
> >        120982 pages non-shared
> >        mconf: page allocation failure. order:1, mode:0x20
> >        Call Trace:
> >        [d1197cb0] [c0008a24] show_stack+0x4c/0x14c (unreliable)
> >        [d1197cf0] [c0058154] __alloc_pages_nodemask+0x468/0x4b8
> >        [d1197d80] [c0077448] cache_alloc_refill+0x2d8/0x55c
> >        [d1197dd0] [c0077780] __kmalloc+0xb4/0x100
> >        [d1197df0] [c02aa6bc] tty_buffer_request_room+0xcc/0x148
> >        [d1197e10] [c02aa8f4] tty_insert_flip_string+0x2c/0xa0
> >        [d1197e30] [c02ab678] pty_write+0x40/0x70
> >        [d1197e50] [c02a6244] n_tty_write+0x260/0x3bc
> >        [d1197eb0] [c02a3780] tty_write+0x1bc/0x260
> >        [d1197ef0] [c007b4d4] vfs_write+0xb8/0x180
> >        [d1197f10] [c007b67c] sys_write+0x4c/0x8c
> >        [d1197f40] [c0013cf4] ret_from_syscall+0x0/0x38
> >        --- Exception: c01 at 0xfef4034
> >
> >                                                        Thanx, Paul
> >
> > ------------------------------------------------------------------------
> >
> > rcu: diagnostic patch for kordex
> >
> > Make sure that the boot CPU has marked itself as online, print out
> > the running CPU's ID, and print a message from within rcu_init_percpu_data()
> > that includes the currently running CPU.
> >
> > Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com> not for inclusion
> > ---
> >
> > diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
> > index 4001833..4f357c4 100644
> > --- a/kernel/rcupdate.c
> > +++ b/kernel/rcupdate.c
> > @@ -175,6 +175,8 @@ void __init rcu_init(void)
> >         * this is called early in boot, before either interrupts
> >         * or the scheduler are operational.
> >         */
> > +       WARN_ON_ONCE(!cpu_online(smp_processor_id()));
> > +       printk(KERN_ALERT "rcu_init() smp_processor_id() = %d\n", smp_processor_id());
> >        for_each_online_cpu(i)
> >                rcu_barrier_cpu_hotplug(NULL, CPU_UP_PREPARE, (void *)(long)i);
> >  }
> > diff --git a/kernel/rcutree.c b/kernel/rcutree.c
> > index f3077c0..207125b 100644
> > --- a/kernel/rcutree.c
> > +++ b/kernel/rcutree.c
> > @@ -1557,6 +1557,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptable)
> >        rdp->passed_quiesc = 0;  /* We could be racing with new GP, */
> >        rdp->qs_pending = 1;     /*  so set up to respond to current GP. */
> >        rdp->beenonline = 1;     /* We have now been online. */
> > +       printk(KERN_ALERT "rcu_init_percpu_data(%d) called\n", cpu);
> >        rdp->preemptable = preemptable;
> >        rdp->passed_quiesc_completed = lastcomp - 1;
> >        rdp->qlen_last_fqs_check = 0;
> >
> --
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