I'm getting weird soft lockups while reading smaps on loaded systems with some background cgroups usage. This issue can be reproduced with the most recent kernel.
Here's the stack trace: [ 1748.312052] BUG: soft lockup - CPU#6 stuck for 23s! [python2.7:1857] [ 1748.312052] Modules linked in: xfs xt_addrtype xt_conntrack iptable_filter ipt_MASQUERADE iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack ip_tables x_tables bridge stp llc dm_thin_pool dm_persistent_data dm_bio_prison dm_bufio libcrc32c nfsd auth_rpcgss nfs_acl nfs lockd sunrpc fscache dm_crypt psmouse serio_raw ppdev parport_pc i2c_piix4 parport xen_fbfront fb_sys_fops syscopyarea sysfillrect sysimgblt mac_hid isofs raid10 raid456 async_memcpy async_raid6_recov async_pq async_xor async_tx xor raid6_pq raid1 raid0 multipath linear crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd floppy [ 1748.312052] CPU: 6 PID: 1857 Comm: python2.7 Not tainted 3.15.5-031505-generic #201407091543 [ 1748.312052] Hardware name: Xen HVM domU, BIOS 4.2.amazon 01/24/2014 [ 1748.312052] task: ffff8800eab41930 ti: ffff8803b9a94000 task.ti: ffff8803b9a94000 [ 1748.312052] RIP: 0010:[<ffffffff81013111>] [<ffffffff81013111>] KSTK_ESP+0x11/0x40 [ 1748.312052] RSP: 0018:ffff8803b9a97c68 EFLAGS: 00000287 [ 1748.312052] RAX: 0000000000000000 RBX: ffff8803b60de3aa RCX: 00007f49ec000000 [ 1748.312052] RDX: 0000000000000001 RSI: ffff8800eba1c730 RDI: ffff880399434b90 [ 1748.312052] RBP: ffff8803b9a97c68 R08: 000000000000000a R09: 000000000000fffe [ 1748.312052] R10: 0000000000000000 R11: 0000000000000007 R12: 0000000000000001 [ 1748.312052] R13: ffff8803b7a74108 R14: 00007f49ec021000 R15: ffff8803b9a9ffff [ 1748.312052] FS: 00007fcc9562b740(0000) GS:ffff8803cfcc0000(0000) knlGS:0000000000000000 [ 1748.312052] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1748.312052] CR2: 00007fcc955ed180 CR3: 00000003b97a5000 CR4: 00000000001406e0 [ 1748.312052] Stack: [ 1748.312052] ffff8803b9a97ca8 ffffffff8117bcc9 ffff8803b9a97df8 ffff880399435030 [ 1748.312052] ffff88003684d000 ffff8800eba1c730 0000000000000000 ffff8803b5dfc980 [ 1748.312052] ffff8803b9a97d38 ffffffff81236612 ffff88030000002d 00007f4900000070 [ 1748.312052] Call Trace: [ 1748.312052] [<ffffffff8117bcc9>] vm_is_stack+0x59/0xe0 [ 1748.312052] [<ffffffff81236612>] show_map_vma+0x212/0x280 [ 1748.312052] [<ffffffff81236805>] show_smap+0x85/0x250 [ 1748.312052] [<ffffffff81237bc0>] ? smaps_pte_entry.isra.21+0x220/0x220 [ 1748.312052] [<ffffffff81236a03>] show_pid_smap+0x13/0x20 [ 1748.312052] [<ffffffff811f6016>] seq_read+0x256/0x3e0 [ 1748.312052] [<ffffffff811d30e1>] vfs_read+0xb1/0x180 [ 1748.312052] [<ffffffff811d335f>] SyS_read+0x4f/0xb0 [ 1748.312052] [<ffffffff8178527f>] tracesys+0xe1/0xe6 [ 1748.312052] Code: 89 f8 48 89 f2 89 c6 48 89 e5 65 48 8b 3c 25 c0 c7 00 00 e8 b2 f9 ff ff 5d c3 0f 1f 44 00 00 48 8b 47 08 55 48 89 e5 48 8b 40 10 <a9> 00 00 02 00 75 10 48 8b 87 10 06 00 00 5d c3 0f 1f 80 00 00 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
