这篇文章是基于上次UWB(WUSB) wireless debug 的一个问题，然后引申出来的一个话题，对kenel有一定理解的同学可能会有一定的帮助。
--其实这个问题，个人认为，这个个CallTrace会一起down机，cpuhold的等问题，还是一个很大的问题。不过从一般意义上来讲，他是个warning我们可以不用管他。但谁让自己是做技术的呢，没办法，眼里容不得沙子。来吧干货。
1. Kernel int request & free
Call Trace:
Apr 7 10:44:56 magic kernel: ------------[ cuthere ]------------
Apr 7 10:44:56 magic kernel: WARNING: atkernel/softirq.c:159 local_bh_enable_ip+0x7d/0xb0() (Tainted: P --------------- )
Apr 7 10:44:56 magic kernel: Hardware name: HPZ420 Workstation
Apr 7 10:44:56 magic kernel: Modules linked in:usb_skeleton(U) wusb_cbaf(U) elok_s(P)(U) tun bridge iptable_mangle iptable_natnf_nat nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 iptable_filter ip_tablessunrpc bnx2fc cnic uio fcoe libfcoe 8021q garp stp libfc llc scsi_transport_fcscsi_tgt cpufreq_ondemand acpi_cpufreq freq_table mperf ipv6 rcim2usb(U)psysdrv(P)(U) esdcan_pci200(P)(U) realtek_uwb(U) vfat fat hwa_hc(U) wusb_wa(U)ext3 wusbcore(U) jbd hwa_rc(U) uwb(U) wmi xhci_hcd nvidia(P)(U) igb dca ptppps_core sg microcode serio_raw i2c_i801 i2c_core iTCO_wdt iTCO_vendor_supportsnd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_hwdepsnd_seq snd_seq_device snd_pcm snd_timer snd soundcore snd_page_alloc e1000eshpchp ext4 mbcache jbd2 sd_mod crc_t10dif sr_mod cdrom firewire_ohcifirewire_core crc_itu_t isci libsas mpt2sas scsi_transport_sas raid_class ahcipata_acpi ata_generic dm_mirror dm_region_hash dm_log dm_mod [last unloaded:scsi_wait_scan]
Apr 7 10:44:56 magic kernel: Pid: 6127, comm:java Tainted: P --------------- 2.6.32-358.11.1.el6.x86_64 #1
Apr 7 10:44:56 magic kernel: Call Trace:
Apr 7 10:44:56 magic kernel: <IRQ> [<ffffffff8106e2e7>] ? warn_slowpath_common+0x87/0xc0
Apr 7 10:44:56 magic kernel:[<ffffffff8106e33a>] ? warn_slowpath_null+0x1a/0x20
Apr 7 10:44:56 magic kernel:[<ffffffff810778dd>] ? local_bh_enable_ip+0x7d/0xb0
Apr 7 10:44:56 magic kernel:[<ffffffff815106db>] ? _spin_unlock_bh+0x1b/0x20
Apr 7 10:44:56 magic kernel:[<ffffffffa0bcd8f7>] ? uwb_rc_set_drp_cmd_done+0x67/0x100 [uwb]
Apr 7 10:44:56 magic kernel:[<ffffffff8108107d>] ? del_timer+0x7d/0xe0
Apr 7 10:44:56 magic kernel:[<ffffffffa0bd0e95>] ? uwb_rc_neh_cb+0x25/0x40 [uwb]
Apr 7 10:44:56 magic kernel:[<ffffffffa0bd11a2>] ? uwb_rc_neh_grok+0x252/0x4d0 [uwb]
Apr 7 10:44:56 magic kernel:[<ffffffffa01e6e39>] ? hwarc_neep_cb+0x59/0x168 [hwa_rc]
Apr 7 10:44:56 magic kernel:[<ffffffff813b4ad4>] ? usb_hcd_giveback_urb+0x64/0xe0
Apr 7 10:44:56 magic kernel:[<ffffffffa0c6a26e>] ? xhci_irq+0x4be/0x17f0 [xhci_hcd]
Apr 7 10:44:56 magic kernel:[<ffffffff81082128>] ? add_timer+0x18/0x30
Apr 7 10:44:56 magic kernel:[<ffffffff810e70ea>] ? __rcu_process_callbacks+0x25a/0x350
Apr 7 10:44:56 magic kernel:[<ffffffffa0c6b5d1>] ? xhci_msi_irq+0x31/0x40 [xhci_hcd]
Apr 7 10:44:56 magic kernel:[<ffffffff810e1670>] ? handle_IRQ_event+0x60/0x170
Apr 7 10:44:56 magic kernel:[<ffffffff8107700f>] ? __do_softirq+0x11f/0x1e0
Apr 7 10:44:56 magic kernel:[<ffffffff810e3dbe>] ? handle_edge_irq+0xde/0x180
Apr 7 10:44:56 magic kernel:[<ffffffff8100de89>] ? handle_irq+0x49/0xa0
Apr 7 10:44:56 magic kernel:[<ffffffff815171bc>] ? do_IRQ+0x6c/0xf0
Apr 7 10:44:56 magic kernel: [<ffffffff8100b9d3>]? ret_from_intr+0x0/0x11
Apr 7 10:44:56 magic kernel: <EOI>
Apr 7 10:44:56 magic kernel: ---[ end trace580801de7dc9f3db ]---
Apr 7 10:44:56 magic kernel: in uwb_rsv_timer
结合Call Trace，我们上相应内核代码：
static inline void _local_bh_enable_ip(unsignedlong ip)
{
WARN_ON_ONCE(in_irq()|| irqs_disabled());
#ifdef CONFIG_TRACE_IRQFLAGS
local_irq_disable();
#endif
/*
* Are softirqs going to be turned on now:
*/
if(softirq_count() == SOFTIRQ_DISABLE_OFFSET)
trace_softirqs_on(ip);
/*
* Keep preemption disabled until we are donewith
* softirq processing:
*/
sub_preempt_count(SOFTIRQ_DISABLE_OFFSET- 1);
if(unlikely(!in_interrupt() && local_softirq_pending()))
do_softirq();
dec_preempt_count();
#ifdef CONFIG_TRACE_IRQFLAGS
local_irq_enable();
#endif
preempt_check_resched();
}
warning是由WARN_ON_ONCE(in_irq()|| irqs_disabled());代码产生的
解决方法
解决了disconnect CallTrace
/drivers/usb/host/hwa-hc.c
static void hwahc_disconnect(structusb_interface *usb_iface)
{
struct usb_hcd *usb_hcd;
struct wusbhc *wusbhc;
struct hwahc *hwahc;
printk("in hwahc_disconnect\n");
usb_hcd = usb_get_intfdata(usb_iface);
wusbhc = usb_hcd_to_wusbhc(usb_hcd);
hwahc = container_of(wusbhc, struct hwahc, wusbhc);
wusbhc_b_destroy(&hwahc->wusbhc);
usb_remove_hcd(usb_hcd);
hwahc_destroy(hwahc);
usb_put_hcd(usb_hcd);
}
static int hwahc_probe(struct usb_interface*usb_iface,
const structusb_device_id *id)
{
…
usb_hcd->wireless= 1;
usb_hcd->irq= -1;
…
}
以上解决了disconnect的问题。
2. Memory page alloc & free
Call Trace
Jun 11 03:09:14magic kernel: [ 263.849177] [<ffffffff81137d09>] ?free_pages+0x49/0x50
Jun 11 03:09:14magic kernel: [ 263.849186] [<ffffffffa01949b2>] ? hwarc_neep_release+0x32/0x40[hwa_rc]
Jun 11 03:09:14magic kernel: [ 263.849202] [<ffffffffa0359f7b>] ? uwb_rc_rm+0x3b/0xd0 [uwb]
Jun 11 03:09:14magic kernel: [ 263.849211] [<ffffffffa01940a1>] ?hwarc_disconnect+0x41/0x70 [hwa_rc]
Jun 11 03:09:14magic kernel: [ 263.849225] [<ffffffff813d5998>] ?usb_unbind_interface+0x78/0x160
Jun 11 03:09:14magic kernel: [ 263.849235] [<ffffffff8137407f>] ?__device_release_driver+0x6f/0xe0
Jun 11 03:09:14magic kernel: [ 263.849241] [<ffffffff813741ed>] ?device_release_driver+0x2d/0x40
Jun 11 03:09:14magic kernel: [ 263.849248] [<ffffffff813730f3>] ?bus_remove_device+0xa3/0x110
Jun 11 03:09:14magic kernel: [ 263.849258] [<ffffffff81370b2d>] ?device_del+0x12d/0x1e0
Jun 11 03:09:14magic kernel: [ 263.849266] [<ffffffff813d1c50>] ?usb_disable_device+0xb0/0x2b0
Jun 11 03:09:14magic kernel: [ 263.849273] [<ffffffff813ca862>] ?usb_disconnect+0xa2/0x1c0
Jun 11 03:09:14magic kernel: [ 263.849280] [<ffffffff813cc6fe>] ?hub_thread+0x75e/0x1820
Jun 11 03:09:14magic kernel: [ 263.849291] [<ffffffff8100969d>] ?__switch_to+0x7d/0x340
Jun 11 03:09:14magic kernel: [ 263.849304] [<ffffffff810a1460>] ?autoremove_wake_function+0x0/0x40
Jun 11 03:09:14magic kernel: [ 263.849311] [<ffffffff813cbfa0>] ?hub_thread+0x0/0x1820
Jun 11 03:09:14magic kernel: [ 263.849320] [<ffffffff810a0fce>] ?kthread+0x9e/0xc0
Jun 11 03:09:14magic kernel: [ 263.849327] [<ffffffff8100c28a>] ?child_rip+0xa/0x20
Jun 11 03:09:14 magickernel: [ 263.849336] [<ffffffff810a0f30>] ? kthread+0x0/0xc0
Jun 11 03:09:14magic kernel: [ 263.849341] [<ffffffff8100c280>] ?child_rip+0x0/0x20
Jun 11 03:09:14magic kernel: [ 263.849345] Disablinglock debugging due to kernel taint
/drivers/uwb /hwa-rc.c
staticvoid hwarc_neep_release(struct uwb_rc *rc)
{
struct hwarc *hwarc = rc->priv;
usb_kill_urb(hwarc->neep_urb);
usb_free_urb(hwarc->neep_urb);
printk("%srd_buffer=%p\n",__func__, hwarc->rd_buffer);
if (hwarc->rd_buffer != NULL){
printk("%srd_buffer=%p\n",__func__, hwarc->rd_buffer);
free_page((unsigned long)hwarc->rd_buffer);
hwarc->rd_buffer = NULL;
}
}
staticint hwarc_post_reset(struct usb_interface *iface)
{
struct hwarc *hwarc = NULL;
ssleep(1);
hwarc = usb_get_intfdata(iface);
if(hwarc == NULL){
printk("hwarc_post_reset:ERROR hwarc is NULL in hwarc_post_reset\n");
return 0;
}
struct uwb_rc *uwb_rc =hwarc->uwb_rc;
return uwb_rc_post_reset(uwb_rc);
}
以上解决了内核Page free的问题。
3. Kernellock
Call Trace
…
About the Spin lock. Kernel lock:mutex_lock semaphore_lock spin_lock atomic_lock
/drivers/uwb/drp.c +913
static voiduwb_rc_set_drp_cmd_done(struct uwb_rc *rc, void *arg,
structuwb_rceb *reply, ssize_t reply_size)
{
struct uwb_rc_evt_set_drp_ie *r =(struct uwb_rc_evt_set_drp_ie *)reply;
unsigned long flags;
printk("inuwb_rc_set_drp_cmd_done!!!!!!!!\n");
if (r != NULL) {
if (r->bResultCode !=UWB_RC_RES_SUCCESS)
dev_err(&rc->uwb_dev.dev, "SET-DRP-IE failed: %s(%d)\n",
uwb_rc_strerror(r->bResultCode),r->bResultCode);
} else
dev_err(&rc->uwb_dev.dev, "SET-DRP-IE: timeout\n");
//spin_lock_bh(&rc->rsvs_lock);
spin_lock_irqsave(&rc->rsvs_lock, flags);
if (rc->set_drp_ie_pending > 1) {
rc->set_drp_ie_pending = 0;
uwb_rsv_queue_update(rc);
} else {
rc->set_drp_ie_pending = 0;
}
spin_unlock_irqrestore(&rc->rsvs_lock, flags);
//spin_unlock_bh(&rc->rsvs_lock);
}
以上解决了内核锁嵌套问题！