WARNING in kthread_bind

总是觉得没有整段的时间，有好多主题没有时间整理，最近一直在忙mtddriver的开发和btrfs qgroup的开发工作。

从今天开始，开始利用零碎的时间，尽量每天记录一点点，不需要什么主题，只是简单的记录。

[ 6515.721139] ------------[ cut here ]------------
[ 6515.721564] WARNING: CPU: 0 PID: 3136 at kernel/kthread.c:332 __kthread_bind+0x61/0x70()
[ 6515.722596] Modules linked in: btrfs(OE) ip6t_rpfilter cfg80211 ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6 nf_defrag_ipv6 ipt_REJECT nf_reject_ipv4 rfkill nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_mangle iptable_security iptable_raw iptable_filter ip_tables sg qxl snd_hda_codec_generic snd_hda_intel ext4 snd_hda_controller ttm snd_hda_codec drm_kms_helper snd_hwdep snd_seq drm snd_seq_device xor snd_pcm raid6_pq mbcache jbd2 snd_timer ppdev 8139too snd 8139cp parport_pc pcspkr i2c_piix4 serio_raw soundcore virtio_balloon virtio_console mii parport i2c_core nfsd auth_rpcgss nfs_acl lockd grace sunrpc xfs libcrc32c sd_mod ata_generic
[ 6515.733237]  pata_acpi ata_piix virtio_pci libata virtio virtio_ring floppy dm_mirror dm_region_hash dm_log dm_mod [last unloaded: btrfs]
[ 6515.735112] CPU: 0 PID: 3136 Comm: mount Tainted: G           OE  3.19.0-rc1+ #55
[ 6515.736172] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 6515.736945]  0000000000000000 0000000071d28679 ffff880065a37bd8 ffffffff816684f4
[ 6515.738061]  0000000000000000 0000000000000000 ffff880065a37c18 ffffffff81076e2a
[ 6515.739138]  ffff880065a37c38 ffff880077e72850 0000000000000000 0000000000000004
[ 6515.740237] Call Trace:
[ 6515.740626]  [] dump_stack+0x45/0x57
[ 6515.741337]  [] warn_slowpath_common+0x8a/0xc0
[ 6515.742138]  [] warn_slowpath_null+0x1a/0x20
[ 6515.742900]  [] __kthread_bind+0x61/0x70
[ 6515.743641]  [] kthread_bind+0x13/0x20
[ 6515.744435]  [] open_ctree+0x1711/0x21b0 [btrfs]
[ 6515.745238]  [] btrfs_mount+0x76e/0x900 [btrfs]
[ 6515.746068]  [] ? pcpu_alloc+0x364/0x680
[ 6515.746878]  [] mount_fs+0x39/0x1b0
[ 6515.747599]  [] ? __alloc_percpu+0x15/0x20
[ 6515.748357]  [] vfs_kern_mount+0x6b/0x110
[ 6515.749100]  [] do_mount+0x22c/0xb60
[ 6515.749778]  [] ? memdup_user+0x46/0x80
[ 6515.750543]  [] SyS_mount+0xa2/0x110
[ 6515.751273]  [] system_call_fastpath+0x12/0x17
[ 6515.752215] ---[ end trace 89e57395ce5cd9f0 ]---

这个问题一般发生在process已经running，然后想bind在cpu上面。 今天发生的情况是kthread_run() 然后 kthread_bind(). 修改方法很简单：

(1) kthread_create()

(2) kthread_bind()

(3) wake_up_process();