On Wed, Dec 26, 2012 at 7:22 PM, Zhouping Liu <zliu@xxxxxxxxxx> wrote: > Hello everyone, > > The latest mainline(637704cbc95c) would trigger the following error when the system was under > some pressure condition(in my testing, I used oom01 case inside LTP test suite to trigger the issue): > > [ 5462.920151] BUG: unable to handle kernel NULL pointer dereference at 0000000000000500 > [ 5462.927991] IP: [<ffffffff811542d9>] wait_iff_congested+0x59/0x140 > [ 5462.934176] PGD 0 > [ 5462.936191] Oops: 0000 [#2] SMP > [ 5462.939428] Modules linked in: lockd sunrpc iptable_mangle ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter ip_tabled > [ 5462.984261] CPU 13 > [ 5462.986184] Pid: 117, comm: kswapd3 Tainted: G D 3.8.0-rc1+ #1 Dell Inc. PowerEdge M905/0D413F > [ 5462.995814] RIP: 0010:[<ffffffff811542d9>] [<ffffffff811542d9>] wait_iff_congested+0x59/0x140 > [ 5463.004411] RSP: 0018:ffff88007c97fd48 EFLAGS: 00010202 > [ 5463.009701] RAX: 0000000000000001 RBX: 0000000000000064 RCX: 0000000000000001 > [ 5463.016818] RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 > [ 5463.023926] RBP: ffff88007c97fd98 R08: 0000000000000000 R09: ffff88022ffd9d80 > [ 5463.031033] R10: 0000000000003189 R11: 0000000000000000 R12: 00000001004ee87e > [ 5463.038140] R13: 0000000000000002 R14: 0000000000000000 R15: ffff88022ffd9000 > [ 5463.045258] FS: 00007f3e570de740(0000) GS:ffff88022fcc0000(0000) knlGS:0000000000000000 > [ 5463.053317] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > [ 5463.059041] CR2: 0000000000000500 CR3: 00000000018dc000 CR4: 00000000000007e0 > [ 5463.066157] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 5463.073276] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > [ 5463.080400] Process kswapd3 (pid: 117, threadinfo ffff88007c97e000, task ffff88007c981970) > [ 5463.088633] Stack: > [ 5463.090646] ffff88007c97fd98 0000000000000000 ffff88007c981970 ffffffff81086080 > [ 5463.098090] ffff88007c97fd68 ffff88007c97fd68 ffff88022ffd9d80 0000000000000002 > [ 5463.105527] 0000000000000002 0000000000000000 ffff88007c97feb8 ffffffff8114b0e3 > [ 5463.112998] Call Trace: > [ 5463.115446] [<ffffffff81086080>] ? wake_up_bit+0x40/0x40 > [ 5463.120826] [<ffffffff8114b0e3>] kswapd+0x6c3/0xa50 > [ 5463.125775] [<ffffffff8114aa20>] ? zone_reclaim+0x270/0x270 > [ 5463.131415] [<ffffffff81085680>] kthread+0xc0/0xd0 > [ 5463.136278] [<ffffffff810855c0>] ? kthread_create_on_node+0x120/0x120 > [ 5463.142786] [<ffffffff8160a0ac>] ret_from_fork+0x7c/0xb0 > [ 5463.148166] [<ffffffff810855c0>] ? kthread_create_on_node+0x120/0x120 > [ 5463.154668] Code: 4e 6d 88 00 48 c7 45 b8 00 00 00 00 48 83 c0 18 48 c7 45 c8 80 60 08 81 48 89 45 d0 48 89 45 d8 8b 04 b5 a0 9a cd 81 85 c0 74 0f <48> 8b 87 00 05 00 00 a8 04 0f 85 98 00 00 00 e8 b3 c3 > [ 5463.174097] RIP [<ffffffff811542d9>] wait_iff_congested+0x59/0x140 > [ 5463.180352] RSP <ffff88007c97fd48> > [ 5463.183824] CR2: 0000000000000500 > [ 5463.203717] ---[ end trace 9ff4ff9087c13a36 ]--- > > I attached the config file, hope it can make some help. Hey Zhouping, Can you please run with the following commit reverted? Hillf commit cda73a10eb3f mm: do not sleep in balance_pgdat if there's no i/o congestion -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>